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dCS 900E / 902E User Manual

1. Menu Sequence dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Menu Items Issue Filt DSD DSD 4 Tone Test 7 Seg Displays the software issue when BI pressed Selects one of several anti alias filter responses The filters should be evaluated by ear Filtl gives the sharpest cut off just below half the sampling frequency This is the normal setting Filt2 Filt3 Filt4 give progressively more relaxed responses degrading the alias performance but sharpening the impulse response This affects the stereo or multi channel image Different filters may be appropriate for different material DSD and DSD 4 modes are only available on the dCS 904 In the dCS 900 amp 902 they are permanently set to Off This accesses a sinewave test generator On the dCS 900 the tone is fixed at 1kHz and 18dBO0 Press Effi to toggle it On and Off On the dCS 902 the tone level and frequency can be adjusted Pressing BIS enters a submenu which accesses the following functions Level The tone level from 120dBO to OdBO It can be changed in 0 1dB steps using the fj and buttons Freq The tone frequency from 0 001kHz 1Hz to just under half the sample rate It can be changed using the J and KEN buttons The step size is 1Hz for tones up to 100Hz 10Hz up to 1kHz and 100Hz above 1kHz On Off Toggles whether the generator is on or off Up Allows the menu to be re entered to
2. Getting Started Here s what to do If the unit does not behave the first time you power up contact your dealer or dCs Check the appropriate mains supply for your local mains is marked on the rear panel If it is using the lead supplied connect the unit to the mains connect no other leads at this stage and switch on The unit will test itself for a few seconds while displaying Next the main display will briefly show or and then the sample rate for example Connect a signal source to the analogue inputs Connect an output e g from AES1 to your system or a DAC Press the Sample Rate button left hand end button to get the sample rate you want dCS 902 only Press the Output Format button right hand end to get the format you want From analogue dCS 900 902 et knekke ZER E amp O OL AES EBU Digital recorder Syren INPUTS Gi Gi Gi Gi See Sst SES SES B i Timecode Figure 1 Recording with a dCS 900 902 Set up like this the dCS 900 902 will operate in Master mode and the system it is connected to will nave to lock to it You should have audio Use any output at 32 kS s or 44 1 kS s or 48 kS s dCS 902 only Use any output for double speed data at 88 2 kS s or 96 kS s Use AES1 AES2 for Dual AES at 88 2 kS s or 96 kS s dCS 900E 9
3. E E T 36 32 kS s E d d 44 1 kS s 48 48 kS s EE IL ku 88 2 kS s Il ITT TL 96 kS s 605 176 4 kS s 66 192 kS s 72 4 78 4 84 1 10 100 Frequency kHz st Figure 19 1 Order Noise Shapers implemented on dCS 90X 3rd Order Noise Shape Plots 36 30 ER 18 124 6 s 0 p TTE EE a Minner g 125 ra 18 4 2 T 24 E KEE I gt g JEE S See 32 kS s 2 a Me 44 1 kS s _ 77 48 kS s 48 J MMM 54 seer TT A re 88 2 kS s BE py eT T TTo E T oer 96 kS s 60 4 176 4 kS s 66 4 192 kS s 72 78 4 84 1 10 100 Frequency kHz Figure 20 3 Order Noise Shapers implemented on dCS 90X dCS 900E 902E User Manual dCs Ltd Manual for Software Versions 1 3x to 1 5x 12 June 2000 Noise Amplitude dB 9th Order Noise Shape Plots 32 kS s 44 1 kS s 48 kS s BEER 96 kS s de 176 4 kS s Je 192 kS s Frequency kHz Figure 21 9 Order Noise Shapers implemented on dCS 90X The noise shaper plots above are all on the same vertical scales for easy comparison and the vertical grid is approximately 1 bit per grid line Note that for the audio band 9 order noise shaping at 176 4 kS s or 192 kS s gives huge gains 8 bits or more This means that recording these formats on 8 channel 44 1 kS s or 48 kS s recording machines that store only 16 bits is quit
4. and long enough at least 12mm or 0 5 e The trimmer may be at the end of its travel try turning it several times the other way It is a 20 turn device The unit slaves to Word Clock but not AES EBU e This can be caused by erroneous system messages Contact your dealer or dCS for advice dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 The Left and Right channels are swapped e Check that the audio input cables are not reversed e Check that the channels are not swapped elsewhere in the system e f using SDIF 2 check that CH1 and CH2 outputs are connected correctly e dCS 902 only In Dual AES mode ensure that the AES 1 output is connected to the input on the destination equipment for the Left channel data probably labelled AES 1 AES A or Left and AES 2 output is connected to the input on the destination equipment for the Right channel data probably labelled AES 2 AES B or Right See the manual of the destination equipment for information One output channel is low or absent e Check that all cables are connected correctly and not damaged Damaged cables are a VERY common source of malfunctions e Check that the balance is not offset elsewhere in the system e If the level trimmers on the rear panel have been adjusted check that one has not been set much lower than the other Clicks or crackles occur on the outputs e Check that all cables are connected correctly
5. un e E a alan 56 57 G ET IR 36 Generator Jevel 3 20 Generator testerete nan ei 3 18 20 Generat r TONG aiherra ie DuegeE ege 3 20 L LED MUG esiii ccveveronteg isa vivenaveveresaueseveusveevoreneneee 12 LED overload rase a e d s ugesi 14 60 LED overload level rrrrrnrnnnrrnnnnnrrnrnnnrnnnnnnvvvnnnnn 13 LED word Jengi 13 M Mode maeter 3 8 14 31 32 Mode slaven riai gece d aa e r e 60 N Noise Shaping rranvrnonvrnnnvenvrvrnnnnrnennn 9 13 16 36 O Overload indication 13 60 P PLL Lock in me 31 RS SUR e ue E EN R Reference active rrrrrnrnnnrnnnnnrrvvrnnnrnnnnnnrsvrnnnnnn 14 remote Control 3 6 21 remote software rnrrnnnnvnnrrnnvvnnnnnvnrnnnnnnnnnrnvnnnn 57 AS 232 eide devil 18 21 28 40 57 S Sample alonment A 32 SDIF 2 Message 47 Signal generator rrnnnnrnnrnronnnrnnvnronnnvnnrnrennnvnnnnrene 3 software ISSUC nosa ne a E R ei 20 software versi Mni e a e a eeh e egen 62 Subframe preamble 32 U Unlocking front panel A 22 V VCXO Accuracn eoi iae eeii 31 VCXO Long Term Stability rrorvrnnnrrnrrvrnnnrnnennne 31 VCXO Temperature Stability eonrrnornrnnnnrnnrnre 31 VCXO frequency adlustment 22 31 W welghting EEN 36 WeIQNTING Feee ceh oc ete sieeve ead ceri tener 36 51
6. 1 0000 us 200 ns div repetitive Trigger Mode Edge E f 2 184 V Figure 15 AES3 in to AES3 out 96 kS s dp running 1 2 00 V div BH lim 3 500 10 00 1 IMR de 13 2 00 V div JBW lim 4 000 VM 10 00 1 IMQ de 2 5000 us 0 000 s 2 5000 us 500 ns div repetitive Trigger Mode Edge E f 2 184 Figure 16 AES3 in to AES3 out 44 1 kS s Manual for Software Versions 1 3x to 1 5x 12 June 2000 dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 AES3 data out is also related to the phase of Word Clock in The scope shots below were taken with the unit sync d to Word Clock Zo running F 7 4 2 00 Vidi BH lim 2 500 REES i 1 000 1 IMQ de 2 2 00 v div BH lim 4 000 10 00 1 1MQ de 1 0000 us 0 000 s 1 0000 us 200 ns div repetitive Trigger Mode Edge 1 E 678 1 mv Figure 17 Word Clock in to AES3 out 96 kS s Zo running T 1 2 00 V div l R BH lim 2 500 SE EE F 1 000 1 pe de i f 2 2 00 Vidiv RENERE DER EE BH lim 4 000 V g Ne Cu EE ae E Ae Si en Afen e DEE ee 10 00 1 IMS de 2 5000 us 0 000 s 2 5000 us 500 ns div repetitive Trigger Mode Edge 1 4 678 1 mv Figure 18 Word Clock in to AES3 out 44 1 kS s dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Noise Shaping 5 The dCS 900 amp 902 use noise shapin
7. 4 set Ref In to Loop For the bottom ADC set Ref In to Loop t The Master Clock helps reduce jitter The units self align quite accurately see section Sample Alignment on page 32 onwards This arrangement will work with one two or more ADC s You can record from the SDIF 2 output or one of the SPDIF outputs if preferred dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Six Channel Set Up Sync ed to Word Clock CH1 CH2 dCS 900 902 S FUSE GAN ON OFF Dupa OupuB oe To digital recorder From analogue sources Clock Figure 7 Six Channel Set Up Sync ed to Word Clock For the top ADC set to the sample rate you wish to record set Ref In to Int Internal sync and select a filter For the other ADC s turn A SL Autoslave On and select a filter If you are recording less than 24 bit words set Word Length as required and set Noise Shaping to Auto on all ADC s The data streams will be synchronous This arrangement will work with one two or more ADC s the top one must be set to Int You can record from the AES outputs or one of the SPDIF outputs if
8. 902 only The VCXO frequency can be trimmed by using the Offst function in the menu see page 22 each VCXO is independently adjustable Synchronising to source Pull in range 300 ppm about nominal frequency Lock in time lt 2 seconds for most situations The PLL is very robust and will lock to very poor signals if necessary Data is decoded using a much wider band faster PLL so AES3 type low frequency jitter on the input clock can be handled and will be cleaned If you need to synchronise several items of digital equipment we recommend using a dCS 992 Master Clock dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x 12 June 2000 Sample Alignment The dCS 900 amp 902 align samples such that Word Clock out aligns with AES3 samples out the rising edge of word clock aligning with the start of the first illegal code in the X Z subframe preamble and the falling edge aligning with the start of the Y subframe preamble The scope shots below were taken in Master mode AR running 1 2 00 V div BH lim 2 500 1 000 1 Dos de 2 2 00 V div BH lim 4 000 10 00 1 IN de 1 0000 us 0 000 s 1 0000 us 200 ns div repetitive Trigger Mode Edge 1 678 1 mv Figure 11 Word Clock and AES3 outputs 96 kS s 42 running 1 2 00 V div BH lim 2 500 1 000 1 508 de 2 2 00 Vr div BH lim 4 000 10 00 1 IM de 2 5000 us 0 000 s 2 5000 us 500 ns div repetitive Trigger Mode
9. Edge 1 f 676 1 mv Figure 12 Word Clock and AES3 outputs 44 1 kS s dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 When Word Clock in is used as a sync source in and out are related as below The lower waveform is the output the upper one is the input The misalignment is less than about 40 nsecs The scope shots below were taken with the unit sync d to Word Clock in AR running 1 2 00 V div BH lim 2 000 d 1 000 1 IM de 2 2 00 YVidiv BH lim 5 500 1 000 1 508 de 1 0000 us 0 000 s 1 0000 us 200 ns div repetitive Trigger Mode Edge 1 Ff 1 500 Figure 13 Word Clock in to Word Clock out 96 kS s 4e running 1 2 00 V div BH lim 2 000 1 000 1 IN de 2 2 00 V div BH lim 5 500 1 000 1 Dos de 2 5000 us 0 000 s 2 5000 us 500 ns div repetitive Trigger Mode Edge 1 f 1 500 Figure 14 Word Clock in to Word Clock out 44 1 kS s dCS 900E 902E User Manual dCs Ltd AES3 in and out are related as below where they are at the same sample rate and the AES3 input is used as a sync source The alignment is better than 40 nsecs Input is at the top of the displays output is at the bottom Signals are at the sockets on the dCS 900 amp 902 and the unit was slaved to AES Ref In 42 running 1 2 00 V div BH lim 3 500 10 00 1 IM de 2 2 00 V div IEN lim 4 000 10 00 1 1M2 de 1 0000 us 0 000 s
10. Reference In connector for AES EBU reference or the Clk In connector for SDIF 2 Word Clock To slave the unit to the Master Clock press the Master Slave button The unit will attempt to lock to the Reference this will take a few seconds If lock is achieved the Slave LED will light up brightly and the Master LED will turn off To return to Master mode press the Master Slave button again If both AES Reference and Word Clock are connected pressing the Master Slave button cycles through the sequence Master AES Reference Word Clock Master etc If the active reference source is lost the unit will select the next option in the sequence If the Auto Slave option see page 21 is turned On the unit will automatically slave when a suitable reference is connected If both AES Reference and Word Clock are connected AES Reference takes priority Word Clock may be selected by pressing the Master Slave button it moves down the priority list dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 dCS 902 only Once slaved the unit can internally multiply the reference input sample rate by 2 if required by pressing the Multiplier button The Master Clock must be set to a suitable sample rate Master Clock Sample dCS 902 Sample Rate kS s Rate kS s 32 32 44 1 44 1 or 88 2 48 48 or 96 88 2 88 2 96 96 Table 1 Reference Clock and Sample Rates For M
11. Software the Menu s rrnxnnvnvrnnnnvnvnnnnnnvvnnnnnnnvnnnnnnnvennnnnnvennnnnnvennnnnnennnnnr 18 Overview 18 Entering the Menu 18 Moving through the Menu 18 The Menu Sequence 19 Menu Items 20 Issue 20 Filt 20 DSD 20 DSD 4 20 Tone 20 Test 20 7 Seg 20 Heat 21 Phone 21 Part 21 S No 21 RS232 21 BNC O 21 Ref In 21 dCS 900E 902E User Manual dCs Ltd Manual for Software Versions 1 3x to 1 5x 12 June 2000 Typical Applications dCS 900 902 Technical Information General Technical Information Options Maintenance and Support TroubleShooting A SL Offst Loc End Six Channel Set Up Sync ed to AES Reference Six Channel Set Up Sync ed to Master Clock AES Six Channel Set Up Sync ed to Word Clock Six Channel Set Up Sync ed to Master Clock Word Clock Operating Several Units on One Remote Chain Recording Dual AES on a 4 Track Recorder Anti Alias Filtering Clocking Internal clock Synchronising to source Sample Alignment Noise Shaping Digital Interface Specifications Analogue Input Specifications AES3 AES EBU Format Message Handling How Far will it Go SPDIF Message Handling SDIF 2 PCM Format SDIF 2 Messaging Power Consumption Size Weight and Operating Conditions Size and Weight Operating Conditions Word Length Reduction What does it look like Mains Voltage Video Frequency VCXOs P3D DSD Pro and Other Formats Ordering Options For A New Unit Having Your Op
12. Systems Sample Rate Multiplier Mute Figure 3 Front Panel The dCS 900 902 uses a combination of front panel buttons for frequently changed functions and a step through menu for features you might set and forget Press the Sample Rate button repeatedly to cycle through the sample rates dCs 900 48 44 1 32 48 etc dCS 902 96 88 2 48 44 1 32 96 etc The dCS 902 also features a Multiplier button which allows you to step through more quickly Press the Multiplier button repeatedly to cycle through in one of the following sequences depending on the starting sample rate 48 96 32 48 96 etc 44 1 88 2 44 1 88 2 etc To change sample rates quickly use the two buttons together For example to change from 88 2 kS s to 96 kS s press Sample Rate once then Multiplier once Do not press the buttons too fast as a delay is built in to the software The sample rate selected is shown on the LED display in the centre of the panel This button forces a mute in addition to the automatic ones The digital outputs are automatically muted at power up and when the sample rate is changed or the unit is locking to a reference source A forced mute is indicated by the mute LED above the mute switch lighting up In normal use pressing the Mute button mutes the digital outputs and lights the mute LED Pressing the Mute button again unmutes the ADC as long as no automatic mute is being
13. XLR female 2 off Input Level Adjustment trimmers Two 20 turn potentiometers set the full scale input levels These are factory preset for full scale with input levels of 20dBu If necessary adjust with a suitable trim tool or a small screwdriver Turn clockwise for increased gain Take care to ensure the stereo inputs remain in balance The trim range is 6dB Reference In 3 pin XLR female AES C Reference Digital Output 3 pin XLR male Reference In is an AES EBU reference input for synchronising the unit to a Master Clock AES C is a Reference loop through directly coupled to it A terminating resistor may be turned on or off using the menu if several units are to be daisy chained AES A amp B Digital Outputs 3 pin XLR male 2 off Two AES EBU outputs which may be used independently dCS 902 only They may also be used as a Dual AES pair at 88 2 or 96kS s SDIF 2 CH1 CH2 Data BNC 2 off These outputs are for SDIF 2 encoded PCM They are both TTL level signals for a 75 ohm line SDIF 2 Clk In BNC SDIF 2 Clk Out BNC This pair take in and give out Word Clock Clock In is terminated and Clock Out is regenerated internally so these lines can be used for daisy chaining many units together SPDIF Outputs RCA Phono amp Toslink optical The RCA Phono connector should be used with a 75 ohm line The Toslink connector should be used with a Toslink fibre optic cable designed for digital audio use Pull out the plastic cover
14. applied dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Word Length Noise Shaping The AES EBU format accommodates data up to 24 bits If a shorter word is needed and the extra bits are just ignored the result is typical digital sound due to the abrupt chopping off of the low level signal information To avoid this the dCS 900 902 allows proper truncation of the data and uses Noise Shaping to maintain low level performance See the section on Word Length Reduction on page 50 for some background on this If you do use Word Length truncation make sure that Noise Shaping is not set to OFF without realising it Pressing the Word Length button repeatedly cycles the word length through the sequence 24 23 22 21 20 19 18 17 16 24 etc The Word Length is briefly shown on the main display and if a setting other than the maximum is set the word length LED above the button lights Noise Shaping is a technique which improves the noise performance of the ADC in the audio band by moving the quantisation noise energy introduced by reducing the word length from the middle of the band where the ear is most sensitive to the top end or ultrasonic region where the ear is less sensitive or insensitive See the section Word Length Reduction on page 50 for more background Pressing the Noise Shaping button repeatedly cycles the unit through 5 noise Shaping characte
15. before use dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Remote In amp Out 9 pin D type male 2 off Mains Supply If the Windows Remote software is in use connecting Remote In to a com port on a PC running the Remote Control program allows the unit to be controlled by the PC Remote Out may be connected to another suitably equipped dCS unit allowing several units to controlled by the same PC In addition the unit may be software upgraded without removing the lid by downloading new software via the Remote In port Connect up Remote ports using a 9 way screened cable fitted with 9 way D type connectors at each end wired pin 1 to pin 1 pin 2 to pin 2 etc Suitable cables are available from dCs 3 pin IEC CEE22 Switched fused and filtered IEC mains connector Additional Information Digital Data Formats As well as connectors the rear panel displays the following information about the unit near the mains supply connector Mains Voltage The actual voltage setting supplied Manufacturers Name and Country of origin dCS Ltd UK The underside of the unit will have a label on that contains a number such as 900 1A2 3B4 5C6 7D8 12345 This is the serial number but it also contains vital configuration information We will need this number all of it to give you support over the phone or to ship you software updates The unit provides five digital data
16. by up to 9 9ppm in 0 1ppm steps Use the Up and buttons to change this setting hold a button down to accelerate the change The trim is remembered Panel Lock normally Off Set to On to prevent unauthorised changes using buttons The menu has to be accessed in the usual way to turn the lock off again Exits the menu dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCS Ltd 12 June 2000 Manual part no DOC0029021E1 Page 23 Document No OS MA D0002 902 1E1 Contact dcs on 44 1799 531 999 email to more desltd co uk inside the UK replace 44 with 0 web site www dcsltd co uk dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 TYPICAL PPLICATIONS Six Channel Set Up Sync ed to AES Reference dCS 900 902 To digital recorder From analogue sources Figure 5 Six Channel Set Up Sync ed to AES Reference For the top ADG set to the sample rate you wish to record set Ref In to Int Internal sync and select a filter For the middle ADG set Ref In to Loop turn A SL Autoslave On and select a filter For the bottom ADG set Ref In to Loop t t
17. i o formats AES EBU often referred to as AES3 Dual AES part of the AES3 spec SDIF 2 SPDIF electrical SPDIF optical For all formats the incoming Channel Status and User messages are handled according to a priority system they are either passed through where this is sensible or generated and inserted by the unit The enhanced AES EBU interface is fully implemented Each channel has its own parity and data validity bit as well as User and Channel Status messages Cyclic Redundancy Counts CRC s are generated from the Channel Status message The Dual AES interface allows a 96 or 88 2 kS s 24 bit signal to be coded as two standard 48 or 44 1 kS s 24 bit AES data streams recorded as four channels on a recorder with standard capacity replayed and decoded back into a single data stream channel pair SDIF 2 message bits are internally set to zero with the exception of the block code which is implemented The SPDIF interface has no CRC s as per definition The data structure for electrical and optical interfaces is identical dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Front Panel dCS 900 Ato D Converter Data Conversion Systems 24 S Sr wee Mae Zi JE ORM een wenn EL Sues kH dCS dCS 902 Ato D Converter Data Conversion
18. of Use High quality 160 dB tone generator Can be noise shaped truncated dCS 902E only Variable tone frequency and level Remembers last settings Lockouts Software upgrade able without opening the box Can be remote controlled from PC dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 CONTENTS Product Featureszuu usaltet E E E E S 3 eol NEN i eE EE E E E E EE AE ES 4 About this Manual 5 Warranty Using Your dCS 900 902 For The First Time rnnnnavvnnnnnnvnnnnnnnvnnennnnnnnennnnnnenn 6 Product Overview 6 What s in the Box 6 Mains Voltages 6 Installing Unit in a Rack 6 Getting Started 8 The Hardware Controls and Connectors ccccsecceceseeeeeeeseeeeeeesneeeeeeenes 10 Rear Panel 10 Front Panel 12 The Software the Menu sss errrnnannnnnnnnnnnnnnnennnnnnnnnnnnvenennnnnnnnnnnnennnnnnnnnnnnnnnenn 18 Overview 18 The Menu Sequence 19 Menu Items 20 Typical Applications au cece wesc EE Seed 24 Six Channel Set Up Sync ed to AES Reference 24 Six Channel Set Up Sync ed to Master Clock AES 25 Six Channel Set Up Sync ed to Word Clock 26 Six Channel Set Up Sync ed to Master Clock Word Clock 27 Operating Several Units on One Remote Chain 28 Recording Dual AES on a 4 Track Recorder 29 ACS 900 902 Technical Information ererererevnrnrevnvenevennnenenenenenenenennnenenenenener 30 Anti Alias Filtering 30 Clocking 31 Sample Alignment 32
19. or invalidate the warranty The manual is designed to be helpful If there are points you feel we could cover better or that we have missed out please tell us Your dCS 900 or dCS 902 is guaranteed for a period of 12 months against faulty workmanship or materials Warranty repairs should only be carried out by dCs or an authorised distributor This warranty will be invalidated if the unit is misused or tampered with in any way dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 USING YOUR dCS 900 902 FOR THE FIRST TIME Product Overview The dCS 900 and 902 ADCs Analogue to Digital Converters are high performance converters designed for studio and live recording applications They are designed to produce very high standard digital output that may be used directly or archived AES3 SPDIF and SDIF 2 PCM formats are all supported Multiple units may be slaved together for stable multi channel operation The unit is mains powered and is housed in a 1U 1 75 high 19 rack mounting case It may be controlled either from its front panel or from a software based remote control running on a PC The last setting is automatically stored on power down so that fixed installations may be set up at leisure installed and then left alone Unauthorised alterations to settings may be prevented by a panel lockout feature The unit is highly software based and more functions and features are
20. per sample with a further 3 bits being used for an illegal code based sync code Of the 8 bits per sample the 8 in the first sample are reserved for system messaging and the rest are for User messages The 4 wires are Ground return Left Channel Right Channel Word Clock The sync codes can enable data recovery without the word clock if necessary but with the number of data formats in current operation this method of locking is strongly discouraged The waveforms below are SDIF 2 waveforms data and word clock at 96kS s and 44 1kS s A running 1 2 00 V div BH lim 3 500 1 000 1 50 amp de 2 2 00 Vr div pos 1 000 1 000 1 502 de 10 000 us 0 000 s 10 000 us pl on 2 00 us div repetitive Trigger Mode Edge 1 fF 1 500 Figure 26 SDIF 2 PCM format at 96 kS s dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 A running 1 2 00 V div pe BH lim 3 500 V rn OE E EEN 2 2 00 Vrdiv pos 1 500 d 1 000 1 508 de 25 000 us 0 000 s 25 000 us pl on 5 00 us div repetitive Trigger Mode Edge 1 Ff 2 500 Figure 27 SDIF 2 PCM format at 44 1 kS s SDIF 2 Messaging The SDIF 2 message is given in the table following The dCS 900 amp 902 implementation sets all bits of the User message to 0 DESCRIPTION Definition Undefined 0000 Oxxx Emphasis No emphasis XXXX XOOX Emphasis 15usec 50usec XXXX XO1X Dub
21. sensitive areas and add back rather more in the less sensitive parts but that s life We still gain some improvements The table below gives the actual noise levels for 16 bit truncated signals with no dither various types of dither noise shaping on its own and noise shaping with dither The 0dB reference level is taken as the minimum noise we could possibly get away with the amount that simple 16 bit truncation 16 bit Q noise would give if it were well behaved which it is not 10 PDF Probability Distribution Function References to Rectangular Dither or Triangular Dither refer the shape of the PDF of the dither dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 11 Straight forward dither always adds noise it can only produce signals with a noise floor higher than Q noise on its own However the noise power added is a few dBs for simple types Noise shaping adds rather more noise but it can be made to add it in parts of the spectrum that the ear is less sensitive to so the perceived noise F weighted noise is lower up to three bits lower It results in a signal that the ear hears as having a far lower noise floor than a 16 bit truncated signal rather than the not much worse of dither alone even though there is really more noise present Truncation Type with Noise Noise Comments 44 1 kS s data rate unweighted F weighted rel 16 bit Q rel 16 b
22. transmits a data structure that conforms to the IEC 958 standard Like the AES EBU this contains 28 bits of Manchester encoded data and a 4 bit near Manchester encoded preamble in a subframe and subframes are further assembled in a block and frame structure The difference lies only in the voltage levels and the Channel Status bits the System Message It contains 24 bits of audio data IMPORTANT The AES EBU interface and the SPDIF interface have similar data structures although the messages are completely different The two structures are identified in the data domain by the use of the Consumer Professional bit bit 1 in the message A I indicates AES EBU format a 0 indicates SPDIF format The default SPDIF message attached to the output data by the unit before being changed by the user is as follows Professional Off Non Audio Off Copy Permit On Format 2 Channel General Format See EN 60958 1995 or IEC958 1989 with amendments 1 amp 2 The structure of the message is sufficiently complex that it is best to read the source material dCS 900E 902E User Manual dCs Ltd Manual for Software Versions 1 3x to 1 5x 12 June 2000 SDIF 2 PCM Format The SDIF 2 interface is a 4 wire NRZ interface so the DC level on each signal line may not be constant It contains 20 bits of audio data and has a block structure of 256 stereo samples rather than the 192 of AES EBU There are 8 bits of message per channel
23. would otherwise form One can trade off filter roll off and energy smear more relaxed roll off gives less energy smear but it may allow some of the signals in the input to alias irrevocably into the output data Once a signal has aliased it cannot be corrected However as far as the ear is concerned this may not matter The ear can tell the frequency of a signal up to a point As the frequency rises the accuracy with which the ear can tell what the frequency is decreases and above a limit all the ear can tell is that there is a signal and it is above kHz It can tell no more So it may be that some degree of aliasing is acceptable to the ear The filters that we have included give increasingly good energy smear performance and consequently have increasingly relaxed roll off FiLT1 gives the sharpest roll off with no aliasing but the worst energy smear Then as the number increases the smear decreases but the aliasing increases Try them to see which you prefer You may find that for different material different filters are appropriate and you may find that for different stages in the recording and mastering process different filters are appropriate The dCS 900 amp 902 use linear phase FIR filters to avoid the limit cycle problems that come with many IIR filters Linear phase gives filters a symmetrical transient response before and after a transient pre ringing The passband may or may not have a ripple de
24. 02E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 If you want to record less than 24 bit data press the Word Length button repeatedly until the required Word Length is displayed and press the Noise Shaping button repeatedly until Auto is displayed Note that all the outputs are active simultaneously on the dCS 900 902 If the mode the unit is in needs them to be different they will be otherwise they will be the same and may all be connected to external equipment simultaneously if required Now you will need to familiarise yourself with how the front panel controls and the menu system work Read the short section on The Software The Menu on page 18 so you know how the buttons and menu work You may also find it convenient to refer to the Function Menu Guide while you are getting to know the unit dCs 9 00E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 THE HARDWARE CONTROLS AND CONNECTORS Rear Panel more OutputB Output e MAINS FUSE 2AT ON OFF Sensitivity Figure 2 Rear Panel All input and output connectors are mounted on the rear panel Individual connectors are clearly identified by the panel legend Viewed from the rear generally from left to right the connectors are as follows Balanced Analogue Inputs 3 pin
25. KS S ersnrrnrnrrrnnnrnnnnnvnnerrrrnnrrnnnnrnnrnnnnennn 46 Figure 27 SDIF 2 PCM format at 44 1 KS S renrrnrnrrnnnnvrnnnnrnnerrrnnnrrrnnnrnnnnnnnrnnne 47 Figure 28 Noise Shaping and Dither Gpecha neen nsnnene 52 Figure 29 Truncation Only Spectra ccceeceeeececeeeeeeeceeeaeeeeeeeseeeeeseaeeseneeeee 53 Figure 30 Changing the Mains Fuse rmansnnnenvvnrvrrrnnnrrnnrnvnnerrrnnrrrennnrnnrnnenrnnne 56 dCS 900E 902E User Manual dCS Ltd Manual for Software Versions 1 3x to 1 5x 12 June 2000 Keywords and Phrases A AES X Z subframe oeeeseeeeeseeeseeeseresreeeeeeseeeeese 32 AES Y eubtrame ioris rieden 32 LE EE 15 60 B Button maslerielave 14 21 60 Button menu down 14 15 18 20 22 Button menu sei 14 18 Button menu Step mrrrrrrrrnnrrrrrnnnrrrnnnrnnnnnnn 13 18 Button menu up 15 20 Button multplier ne 12 15 Button ul EEN 12 Button noise Shaping eee eeeseeeeeeneeeeeeeeeees 9 13 Button output format 8 15 Button overload level rrrrrrrrnnrnrervnrrnnnnnrnnvvvvnnnr 13 Button sample rate 0 ccscceeeeeeeeeeseeeeeeeees 8 12 Button word Jengih 9 13 D Display mode rnrnrvvnrvnnnnnnvnvnnvnnvnvnrnnvnnnennrennnnner 15 RI 50 Dither TR 50 DSD wii EE 20 54 F eege eege ebe eege ee 30 Filter FIR aena Stel EE 30 Filter IIR Filter selection rrrrrrrnnnnrrnorrnnrnnnnnnrvvrnnnrnnnnnnnner 20 Filter transient response 30 36 FUSE
26. Noise Shaping 36 Digital Interface Specifications 39 Analogue Input Specifications 41 AES3 AES EBU Format 42 SPDIF 45 SDIF 2 46 Power Consumption 48 Size Weight and Operating Conditions 49 General Technical Information snanernnnrnnnnnnnnnvnnnnnnennnnnnnnnnnnnnnennnnnnnnnnnnennennnnn 50 Word Length Reduction 50 OpllOns eruen e eee ete ete i ei nett 54 Maintenance and Support rensnavenennnnvnvennnnvnnennnnvnnennnnnnnennnnnnvennnnnnnennnsnnnennnnnnnnn 56 Hardware 56 Software 57 Hardware Update or Calibration 57 Safety and Electrical Safety 57 TROUDICSNOOUIG 2egregegeee iaieineea aa raa ienaat iant ea Wenna Arana SNARE aiSia 58 Error Codes and Messages 58 Internal Device Error Codes 58 System Messages and Error Codes 59 Trouble Shooting Your System 59 ACS SUpport c h ete eS hee ei ns died 61 dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 wish 61 If You Need More Help 61 Other Information 61 Indexes and Software Version Numbers asasasnnannnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnne 62 About this Manual IMPORTANT Warranty Note that there is a fuller Contents at the end of the manual page 63 along with an index and lists of figures and tables References to other sections in the text have the Section Name page in quotation marks and bolded Important information is presented like this ignoring this may cause you to damage the unit
27. added from time to time Software updates from dCS are free What s in the Box The contents of the box are at least dCS 900 or dCS 902 User Manual Function Menu Guide Mains Lead 2 Spare Fuses Remote cable Remote software Mains Voltages The dCS 900 902 is shipped with its mains voltage preset for operation in the destination country The voltage is not intended to be changed by the user If it needs to be changed contact your dealer or dCs Installing Unit in a Rack The unit is supplied with 19 rack mount ears fitted If it is to be installed in a 19 rack the ears supplied may be used to locate it in the rack but IMPORTANT The ears should not be used as the only mechanical support The unit should rest on a Shelf or be supported in some other way The ears will just locate it in the rack and stop it sliding forwards If the unit is not to be rack mounted the ears may be removed Free if we email them and you download from a PC com port Low cost if you ask us for EPROMs or other media we charge for media and handling dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCS Ltd 12 June 2000 Manual part no DOC0029021E1 Page T Document No OS MA D0002 902 1E1 Contact dcs on 44 1799 531 999 email to more dcsltd co uk inside the UK replace 44 with 0 web site www dcsltd co uk dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000
28. ailable for your equipment call us or email us with your unit s serial number Hardware Update or Calibration You may wish to have your unit updated occasionally dCS offer this service we will install any modifications or updates that have occurred since your unit was first shipped and give the unit a full retest to current standards The price will depend on the hardware changes necessary so contact your dealer or us In order to ensure speedy turn around please contact us prior to returning the unit Safety and Electrical Safety IMPORTANT There are no user serviceable parts inside the dCS 900 amp 902 and so there is no need to remove the covers apart from front panel software updates If for some reason you do Disconnect from the mains before removing any covers or changing the fuse There are no substances hazardous to health inside the dCS 900 amp 902 dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 TROUBLESHOOTING Error Codes and Messages The error codes reported by dCS 900 amp 902 provide an effective means to diagnose the majority of problems that may be encountered in use including problems with the overall system the unit operates in internal device warnings and internal device failures Please note that through damage or component failure the unit self check may fail to operate If this happens please contact your distributor or dCS for assistan
29. and not damaged e Check that the overload LED does not light on signal peaks Periodic clicks occur in the recording e f you are using a Master Clock check that the ADC AND the recorder are sync ed to it The unit fails to slave to a Master Clock e Press the Master Slave button to select Slave mode If a suitable reference is connected the LED should light and the unit should lock after a few seconds e Check that the Reference In or Clk In cable is connected correctly and not damaged e Check that the Master Clock is switched on set to the right sample rate and does not require re calibration e Connect a different piece of digital equipment to test the locking capability of the unit If the condition persists contact your Distributor or dCs The Overload indicator will not go out e Remove any input and reference input If the condition persists contact your dealer or dCS the unit may be faulty External meter does not show overload dCS 900 902 does e The dCS 900 902 monitors a number of internal points and data word values in its calculation of overload This may cause it to indicate an overload while the final external data word may not show it for example with a very narrow but large spike that the low pass decimation filter may broaden out sufficiently that the output data does not saturate It is likely that if the dCS 900 902 says it is in overload it is You can choose to ignore it e Some digital meter
30. bing Prohibit Dubbing allowed XXXX XXXO Dubbing inhibited XXXX XXX 1 Block Code Start of block XXXX XXXX 1 Not start of block XXXX XXXX 0 Table 10 SDIF 2 Message Table dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Power Consumption The dCS 900 amp 902 have a linear power supply and so power consumption changes as the mains voltage changes The internal regulation is comparatively efficient for a linear supply so these changes are kept to a minimum Consumption is independent of mains voltage selector switch setting Power Consumption with Mains Voltage measured as AC power into mains socket Nominal mains 25 W Mains 10 22 W Mains 10 27 W The actual intended supply voltage is shown on the rear panel 50Hz or 60Hz operation is not important the unit can use either In general users will not need to change the mains input configuration If you do need this to be done please see the section Having Your Options Changed page 54 in this manual and contact your distributor or dCs dCS 900E 902E User Manual dCS Ltd Manual for Software Versions 1 3x to 1 5x 12 June 2000 Size Weight and Operating Conditions Size and Weight The dCS 900 amp 902 dimensions correspond to a standard 2U 19 rack mount case Four heavy duty feet fitted to the base extend the overall height to slightly greater than 2U Dimensions Width 430mm s
31. c units Use JJ and BEN to change this address if you are operating several units in a multichannel set up On dCS 900 press or hold down the Master Slave button to change this setting IMPORTANT Each unit in a daisy chain MUST be set to a different RS 232 address BNC O This feature is available on the dCS 904 only In the dCS 900 amp 902 it is permanently set to SDIF Ref In Sets the mode of the AES Reference In AES C Out connectors The options are Loop Loops the Reference In through to the AES C output with no termination resistor termination is then about ikohm so several units can be daisy chained Loop t As above but terminates the input Use at the end of a daisy chain Int The output and input in parallel beware is internally driven with the same signal as AES 1 A SL Turns Auto slaving On or Off When set to On connecting an AES EBU reference or a word clock in causes the unit to slave and lights the Slave LED If both are present the unit picks the highest priority one AES EBU unless the Master Slave button is used to move down the priority list When set to Off the unit does not react when a reference is connected IMPORTANT Ensure the Ref In menu item is set to Loop or Loop t before connecting an AES Reference dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Offst Loc End dCS 902 only Trims the appropriate VCXO frequency in master mode
32. ce Internal Device Error Codes Sometimes the unit may misbehave If there is an internal reason an internal device error code may be displayed as follows Err xy an error xy see table below has been detected where xy values have the following meanings Code Description 01 E memory EEPROM not present 02 Error initialising DSP 03 Error loading DSP 04 Error initialising DSP for coefficients 05 Error initialising DSP for coefficients 06 Error loading DSP coefficients 07 Error loading DSP coefficients 08 Error sending command 09 Error sending command 10 Error sending command 11 Error sending command 12 Error with LSB MSB configuration 13 Error with LSB MSB configuration 14 Error with LSB MSB configuration 15 Error configuring FPGA 99 DSP error Table 12 Internal Error Codes If you get any of these please contact dCS with as much information as possible to help us re create the problem Some of these may have hardware problems as their cause some may have software dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 System Messages and Error Codes Some other messages may be displayed that give indications of errors from other sources outside the unit Display Description n Aud The data has been flagged by an AES3 message as non audio perhaps a CD ROM This message may also be displayed briefly when the sample sample rate is changed Hot Th
33. dCS 900E 902E Analogue to Digital Converter User Manual Software versions 1 3x to 1 5x 12 June 2000 1994 1996 2000 dCs Ltd All rights reserved Reproduction of this manual in any manner whatsoever without the written permission of dCs is strictly forbidden Additional copies of this manual may be obtained from dCs Information contained in this manual is subject to change without notice and whilst it is checked for accuracy no liabilities can be accepted for errors dCS Ltd is Data Conversion Systems Ltd Company registered in the England no 2072115 dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCS Ltd 12 June 2000 Manual part no DOC0029021E1 Page 2 Document No OS MA D0002 902 1E1 Contact dcs on 44 1799 531 999 email to more dcsltd co uk inside the UK replace 44 with 0 web site www dcsltd co uk dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x 12 June 2000 dCs Ltd PRODUCT FEATURES Formats PCM at 32 44 1 or 48 kS s dCS 902E only PCM at 88 2 or 96 kS s Data formats supported are AES EBU XLR SPDIF RCA Phono SPDIF optical Toslink and SDIF 2 BNC dCS 902E only Dual AES XLR Syncing Master mode or can sync to Word Clock or AES reference Sync to video option available Functions Very high performance ADC free from gain ranging Multichannel Sync capability Noise shaping truncation 1 3 9 order Test Generator Ease
34. e practical and there is in practice very little quality loss dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Digital Interface Specifications AES EBU AES3 Output Type Balanced differential Impedance 110 110 Sensitivity unloaded 1 10 7 Maximum Wordlength 24 24 Damage level gt 20 Connector XLR3 female XLR3 male Connections Ground or shield Signal Signal Table 4 AES EBU i o specifications SDIF 2 Type Single ended ground referred Impedance 100 25 Sensitivity unloaded TTL Maximum Wordlength 24 24 Damage level gt 10 Time skew Word Clock in out lt 40 Connector BNC x 1 BNC x3 Connections CH1 left CH2 right Word Clock In amp Out Table 5 SDIF 2 i o specifications SPDIF electrical Output Type Single ended ground referred Impedance 75 Q Sensitivity unloaded 1 0 V pk pk Maximum Wordlength 24 bits Damage level gt 10 V pk pk Connector RCA Phono Table 6 SPDIF electrical output specifications dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 SPDIF optical Output Type Optical Maximum Wordlength 24 bits Wavelength 660 nm Connector Toslink EIAJ CP 340 Table 7 SPDIF optical output specifications Remote control interface Input Output Type RS 232 Level RS 232 Data Format Contact dCs Connector 9 way D type male Table 8 R
35. e unit is overheating and performance may suffer Ouch The unit is seriously overheating and may be damaged shortly Switch off Bad Fs The sample rate coming in is not one the unit can lock to or there is an input signal quality problem Table 13 System Error Codes Trouble Shooting Your System If you experience difficulties when using your dCS 900 902 the following suggestions may help to resolve the problem The unit fails to power up e Ensure there is power available on the mains cable and the unit s mains switch is On e Check the rated supply voltage shown on the rear of the unit matches the local supply voltage e Check that the fuse has not blown if so correct any obvious cause then replace the fuse as described in the section User Changeable Parts page 56 e Check that the mains cable is pushed fully home into the mains inlet in the rear of the unit The audio output is low or absent e Check that all cables are connected correctly and not damaged Damaged cables are a VERY common source of malfunctions e Check that the source and destination equipment are switched on and correctly set up e Check that an audio signal is present on one or both of the inputs e Ensure Mute is not enabled LED off The level trimmers on the rear panel do not change the input level e Ensure the trim tool or screwdriver you are using is narrow enough to reach the adjuster about 2 5mm or 0 1 diameter
36. ee note i Height without feet 44 mm 2U Height with feet 52 mm Depth 390 mm see note ii Weight 6 8 kg see note iii note i Removable 19 rack mount ears are supplied taking total width to 483 mm 19 note ii Measured from front panel to rear panel connectors Additional depth should be allowed to accommodate cable connectors note iii The high quality case is necessarily heavy Operating Conditions The case of the dCS 900 amp 902 have no ventilation slots or fan cooling to give It dissipates relatively low power so that usually allowing natural convection provides enough cooling Do not install the unit near heat sources such as radiators air ducts or direct strong sunlight Ambient should not exceed 50 C should not fall below 0 C and should be a non condensing If in doubt the easy consideration should be paid to appropriate support shelving when installing the units in a rack quiet operation does not need to be installed in a machine room internal temperature stability improved electrical safety long term reliability no regular maintenance or cleaning requirements test is the dCS 900 amp 902 are happy to work anywhere a human is dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 GENERAL TECHNICAL INFORMATION Word Length Reduction Word length reduction truncation causes an error signal to be added to the wanted signal The error si
37. emote Control Interface Details dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Analogue Input Specifications Balanced Inputs Type Balanced Format AES14 1992 Impedance 5 kQ 5 kQ CMRR gt 100 dB spec gt 120 dB typ gt 108 dB typ gt 80 dB typ gt 74 dB typ Level for Full Scale 20 dBu as shipped Trim range 6 dB Connector type XLR3 female Connections Ground or shield Signal Signal Table 9 Analogue XLR Interface Details The analogue inputs are balanced not floating with a stable high common mode rejection ratio Either input may be used on its own with the other floating if single ended operation is wanted dCS 900E 902E User Manual dCs Ltd AES3 AES EBU Format Message Handling IMPORTANT 8 AES3 1992 ANSI S4 40 1992 The AES EBU interface transmits a data structure that conforms to the dCS version of AES3 1992 This contains 28 bits of Manchester encoded data and a 4 bit near Manchester encoded preamble in a subframe and subframes are further assembled in a block and frame structure Each subframe contains The default AES EBU message attached to the output data by the unit before preambles to allow the receiver to sync up up to 24 bits of audio data transmitted Isb first V a validity bit U a user bit for the User Message C a Channel Status bit for the System Message P a parity bit The AES EBU int
38. ent the transfer function that the wanted signal sees is the convolution of the PDF of the second signal and the staircase function The converse is also true the transfer function the additional signal sees is the convolution of the PDF of the wanted signal and the staircase function This aspect is not a problem with the dither types considered below but it can be with some highly frequency shaped dithers The trick is to make the second signal as inaudible as possible It is usually referred to as dither and it is usually noise like because then its statistics can be controlled and the converse effect of the signal modulating the dither can be made insignificant or zero However there are a number of ways that this dither signal can be generated and treated The major options are e generate it from the signal or generate it independently and add it Dither It seems implausible that the dither signal can be generated from the signal but it can and this gives the lowest added noise power option It is noise shaping on its own but there are some circumstances where it needs help from additional dither e add inside or outside an error shaping loop e frequency shape to match the ears response or not One can use techniques that suppress error energy in the areas where the ear is sensitive and put it in areas where the ear is not sensitive Usually this shuffling around process costs something we remove a little from the
39. enu operation as the button see the section on page 18 Output Format Menu Up dCS 902 only The Output Format button is dual function on its own blue type on the front panel it sets the output format to Single AES 1 or Dual AES 2 With the other menu buttons MMG type on the front panel it is the menu fy button Pressing the Output Format button repeatedly causes the output format to cycle through the allowed options from the sequence Single AES Dual AES Single AES etc For sample rates of 48kS s or less Single AES is the only option IMPORTANT If the Output Format is set to 2 Dual AES do not use the SPDIF or SDIF 2 outputs For Menu operation as the JJ button see the section The Software The Menu on page 18 Mode Display dCS 902 only The single digit LED mode display to the right of the Output Format button shows the output format Display Output Format 1 Single AES 2 Dual AES Table 2 Output Data format indication higher sample rates When the Output Format is selected the main display briefly shows the format code Al for Single AES Standard speed encoding bl for Single AES Double speed encoding b2 for Dual AES Standard speed encoding In Single AES mode the same data stream is available on both AES outputs In Dual AES mode the data stream is available on AES A amp AES B outputs dCS 900E 902E User Manual dCs Ltd Manual for Software V
40. erface and the SPDIF interface have similar data structures although the messages are completely different The two structures are identified in the data domain by the use of the Consumer Professional bit bit I in the message A I indicates AES EBU format a 0 indicates SPDIF format being changed by the user is as follows For more information on the way dCS implement the AES3 system message to handle higher sample rates see the Appendix to this manual For the formal Professional On Non Audio Off Mode Stereophonic Source DCS1 Destination null definition of the AES3 interface see footnote from the AES transmission format for two channel linearly represented digital audio data Manual for Software Versions 1 3x to 1 5x 12 June 2000 AES Recommended practice for digital audio engineering Serial dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 How Far will it Go The AES EBU format was designed to go reasonable distances at 44 1 kS s and 48 kS s Figure 22 and Figure 23 below show it over 16 m and 94 m using average cables The waveform at 94 m can still be decoded although it is quite degraded Cable delay is about 5 6 nsecs metre At 96 kS s twice the data rate the format was designed for the allowed cable length is less Figure 24 and Figure 25 below show this over 16 m and 94 m At 16m the waveforms are still very good but at 94m they are reall
41. ersions 1 3x to 1 5x 12 June 2000 dCS equipment encodes messaging into the various data streams to enable receiving equipment to tell what is going on and to decide which wire is which in the unlikely event of user wiring errors Not all equipment from other manufacturers does this so IMPORTANT Take care when connecting Dual AES as it is easy to connect the wires in the wrong order If this is not detected the Left and Right channels will be swapped on the recording Numbering each connector is a sensible precaution Sample Rate Display The main LED display generally shows the sample rate in kS s When other parameters are set it briefly shows the new setting Word Length Noise Shaping etc then reverts to its normal display In the case of an error condition it will display an error message If the unit is being slaved the display also indicates which input connector it is slaved to XXX b xxx r XXX d xxx XXX Important error messages are given below a full list is given in the section The sample rate in kS s 82 44 1 48 88 2 or 96 Slaved to Clk In Slaved to AES Reference in Temporary display during locking the unit has detected the base reference sample rate and is attempting to lock to it Temporary display during locking the unit is lining up Clk Out to Clk in Error Codes and Messages on page 58 BadFs Err xy Hot Ouch blank The clock source is not in pull
42. for repair Fuse Type 20 x 5mm 2 amp HRC fuse If the fuse should fail it is essential that it be replaced with one of the same type Failure to do so could result in damage to the unit and may invalidate the guarantee To gain access to the fuse remove the IEC mains connector use a small flat bladed screwdriver to pry up the tab on the fuse carrier and pull it out Push the fuse out of the clip in the carrier and replace it with a new one Push the carrier back into the unit so that it clicks home Remove Fit MAINS FUSE 2A T ON OFF old fuse new fuse N I S Geog H ES SE 5 fo e SE lt lt oL ge So aa Figure 30 Changing the Mains Fuse Disconnect from the mains before changing the fuse dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Software Installing New Software The operating software can be downloaded via the RS 232 link from a PC com port using the Windows Remote software running on the PC To use this follow the installation instructions on the floppy discs the remote software is supplied on Then run the remote programme with whatever units you want connected The software will scan the RS 232 chain for units this takes a while to see what is connected It then reports back and for each there is an info button This gives you the option of installing new software in that unit To find out if there are any software updates av
43. g that is optimised to the F weighting curve It does not affect signal frequency or transient response but shapes the frequency response of errors Q noise or truncation errors so that they fall as much as possible in the less sensitive part of the spectrum For all the major sample rates 32 kS s 44 1 kS s 48 kS s 88 2 kS s 96 kS s the noise shapers have been individually optimised The 1 3 and 9 shapes for 44 1 kS s agree well with Wannamaker s published results Noise Shaping adds more noise power but because of the shaping it is perceived as lower noise There is a compromise to be drawn as more aggressive shaping is used more noise is added and less perceived improvement occurs In practice things stop improving much above the 9 order The increased real noise power can cause small clicks in editing if this is carried out after the shaping For this reason noise shaping should be used as late as possible in the mastering process we recommend recording at the very highest possible sample rate and resolution and only reducing either at the latest possible minute If however you have to reduce word length the perceived noise gain taking into account the ear s response and the actual increase in noise mainly out of band in given in the table below Sample Perceived Actual Perceived Actual Perceived Actual Rate Gain F Increase Gain F Increase Gain F Increase kS s weighted in Noise Weighted
44. gnal is usually referred to as Q noise or Quantisation noise the approximation is usually made that the errors are noise like This is reasonably true for large signals where the errors are very complex if they are not exactly noise like Importantly though for smaller ones it is not so As the wanted signal gets smaller the complexity of the error signal decreases The errors first of all pile into ever fewer lower order harmonics or intermodulation products and then as the level of the signal sinks below the Q level the majority of the error power piles into the signal fundamental This causes its amplitude to become unpredictable it may drop abruptly to zero and disappear or it may cease to go down any more and just stay at a constant level From the audio viewpoint this sounds very unpleasant As a signal tail decays away the tonal quality changes and then it decays into distorted mush and then either abruptly stops or else keeps fuzzing away until a new signal starts The level at which all this happens is the Isb of the output word for CDs it is at the 16 bit level which equates to about 90 dBO This level is high enough to be quite audible and the effect must be tackled to make reasonable quality end product There is really only one way of tackling the problem another signal has to be added to the wanted one to smooth the staircase transfer function that truncation causes Mathematically with two signals pres
45. ies this further The principle is the same but with DSD there is more noise than there is signal even at full scale It is just that it is in a part of the spectrum the ear cannot hear 12 16 bit Q noise is 98 1 dB relative to a full scale sine wave dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 There is another option not supported by the dCS 900 amp 902 generate the dither independently of the signal and frequency shape it prior to addition but do not add it in an error shaping loop This seems to dCS to combine the worst of all worlds the high noise floor in the 0 6 kHz area of straight dither and the high total noise of noise shaping However some people use it What does it look like Figure 28 gives the spectra of 16 bit truncated 44 1 kS s signals with a 90dB sine present for two dither only signals Top Hat Noise Shaped Triangular and with a 10 order noise shaped signal generated and processed by a dCS 972 The equivalent simply truncated spectrum is shown in Figure 29 separately because it is so revolting In it we can see that at the signal level shown 90 dB error power from the quantising truncation is beginning to pile into the fundamental which is showing an amplitude error of 1 3 dB as well as all the unwanted harmonics This would show up on a conventional linearity plot although the sign of the error could be either way We see that the
46. in Noise Weighted in Noise SE Order 4st Order ge Order gid Order gin Order gh Order dB dB dB dB dB dB 32 3 3 1 9 7 5 4 2 8 1 6 1 44 1 5 5 2 4 10 5 6 9 17 9 23 4 48 6 2 2 5 11 7 7 6 21 0 23 8 88 2 11 1 2 8 23 8 11 3 42 2 24 0 96 11 8 2 9 25 7 11 3 45 3 22 5 176 4 17 0 3 0 40 6 12 6 63 0 21 8 192 17 7 3 0 42 8 12 6 65 9 21 8 Table 3 Noise Shaper Gain by Order and Sample Rate The 3 order shaping tends to follow the E weighting curve by chance The g order is very aggressive and can give very large gains at the higher sample rates For example 176 4kS s or 192kS s material truncated to 16 bits so it can be stored on a DA 88 or ADAT loses nothing in the audio band in terms of perceived noise with 3 or 9 order shaping For more information on this topic either see section Word Length Reduction on page 50 or read the references below It actually uses an Error Shaping architecture but the name is now being used for entirely other things and is less well known so we call it erroneously Noise Shaping Minimally Audible Noise Shaping S P Lipshitz and R A Wannamaker J AES vol 39 no 11 p836 852 Psychacoustically Optimal Noise Shaping R A Wannamaker J AES vol 40 no 7 8 p611 620 dCS 900E 902E User Manual dCs Lid Manual for Software Versions 1 3x to 1 5x 12 June 2000 1st Order Noise Shape Plots T a ao ER 2
47. in range or is poorly formatted The unit cannot lock to it An error has been detected Please refer to Internal Device Error Codes on page 58 for more specific details on error codes The unit is overheating probably due to inadequate ventilation Please check positioning and cooling The Hot warning has been ignored and the unit is getting so hot damage may follow If the display is completely blank for any significant period try switching off for 10 seconds then switching on again If this does not solve the problem contact your distributor or dCs The display is also used for Menu options dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCS Ltd 12 June 2000 Manual part no DOC0029021E1 Page 17 Document No OS MA D0002 902 1E1 Contact dcs on 44 1799 531 999 email to more desltd co uk inside the UK replace 44 with 0 web site www dcsltd co uk dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 THE SOFTWARE THE MENU Overview The dCS 900 902 has many other functions that either need to be accessed only occasionally or are informative in nature These functions can be accessed either by the Remote software running on a PC and connected to the unit by an RS 232 link or in most cases by the Menu If a function is set by the menu or the Remote the unit remembers it and it will be set this way for ever or until you se
48. ing circuitry for overload conditions The analogue input sensitivity trims mounted on the rear panel should be set so that the overload indicator does not light on signal peaks The overload indication given by the dCS 900 902 is comprehensive The detection circuitry monitoring the digital filter does not simply check the final output word but all the data from which the output word is formed If any of these overload this may not be apparent from the output data an overload is flagged The filter itself has sufficient numerical accuracy that if the input data is not overloaded the filter computations cannot generate an overload only a raw data overload can cause an error The overload indication is thus much more accurate than any external meter based indication for this reason it is stored in the AES EBU validity bit for later reference The B button is used with the other menu buttons MMG type on the front panel See the section The Software The Menu on page 18 The Master Slave button is dual function on its own blue type on the front panel it sets the clocking mode master or slave With the other menu buttons Miles type on the front panel it is the menu PENN button In Master mode the calibrated voltage controlled crystal oscillators VCXOs inside the unit generate an accurate sample rate The LED labelled Master will be lit to indicate this If a Master Clock is available this may be connected to the
49. ions 1 3x to 1 5x dCs Ltd 12 June 2000 The Menu Sequence To access the Function Menu hold down the Menu Step button and press the Menu Set button To step through the Menu items press the Menu Step button repeatedly To select an item or one of its options press the Menu Set button dCS 900E Use Master Slave button to alter RS232 address dCS 902E Use Menu Up amp Menu Down buttons to alter RS232 address Tone Level and Tone Frequency To exit the Function Menu either select the End item or wait five seconds Displays the Selects an DSD mode is DSD mode is fitted software alternative available on the available on the issue number filter dCS 904 only dCS 904 only Opens the Function Menu Filt 4 Filt 2 Displays dC S Displays the Disables the 7 Turns on and i e R ispl telephone internal segment display ans a display sets dCS 902E self test routine number temperature when idle only a test tone Fahrenheit Level dB On Off Sets the mode of the AES Ref I O connectors Displays the Displays the Displays and This feature is control PCB control PCB sets the unit s available on the part number serial number RS232 address dCS 904 only 0002 540 0 99 SDIF dCS002540 dCS 902E only Locks out the g e Automatically Exits the Trims the front panel slaves when ref Function Menu mastermode A i controls input available sample rate v1 5x software 0 ppm 9 9 ppm Figure 4
50. it Q noise noise 16 bit truncation 0 dB 0 dB Unpleasant low level effects 16 bit truncation with 3 dB 3 dB Okay can show Top Hat dither noise modulation at low signal levels 16 bit truncation with 4 8 dB 4 8 dB All noise Triangular dither modulation and unpleasant effects removed but noise floor is high 16 bit truncation with 4 8 dB 1 2 dB All noise Noise Shaped modulation and Triangular dither unpleasant effects removed Not much perceived noise penalty 16 bit truncation with 3 6 9 dB 10 5 dB Okay with input order noise shaping and noise floors down to no dither 102 dB 16 bit truncation with 3 11 0 dB 9 2 dB Unconditionally free order noise shaping and from truncation Noise Shaped effects with all Triangular dither inputs 16 bit truncation with 9 23 4 dB 17 9 dB Okay with input order noise shaping and noise floors down to no dither 120 dB 16 bit truncation with 9 28 2 dB 16 7 dB Unconditionally free order noise shaping and from truncation Noise Shaped effects with all Triangular dither inputs Table 11 Dither and Noise Shaping Noise Powers Noise shaping on its own is not perfect It relies on a small amount of noise in the input signal to generate the frequency shaped correction signal and if there is very low noise in the input signal this mechanism can break down With ADCs however this situation does not arise because of the analogue noise in the ADC and the input signal DSD carr
51. noise shaping approach maintains low noise in the critical audio mid band Noise Shaper and Dither Only Comparison dCS 972 SW v1 54 60 16 bit truncation Noise Shaped Triangular dither 80 16 bit truncation Top Hat dither etree 16 bit truncation high order noise shaping only E PE kull i a ME D 1 pe tt ae S 100 i Ba E o S Gs S Si D RDO SOL NS d 2 ee e 120 LONG ENT ve E T E E ae e pn 140 es ft rd a TT 160 0 2 4 6 8 10 12 14 16 18 20 22 Frequency kHz Figure 28 Noise Shaping and Dither Spectra S for comparison with the table 10 and 9 order noise shaping are very similar dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCS Ltd 12 June 2000 Spectra of 90dB 24 bit sinewave truncated to 16 bits with dither options dCS 972 SW v1 54 60 24 bit source data 80 settee 16 bit truncation no dither i 89 70 dB 16 bit truncated 91 00 dB source signal 100 a V 2 ti i 2 n 8 f r S e i 4120 05 i 140 gt TE No a Mi 2 160 O i na H AU LANA l 0 2 4 6 8 10 12 14 16 18 20 22 Frequency kHz Figure 29 Truncation Only Spectra dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 OPTIONS Mains Voltage We ship with the mains wired according to the destination The voltage option should be specified when the unit is orde
52. pending on the filter being used The stop band is typically below 110 dB and can be as low as 130 dB See for example Principles of Digital Audio 3rd Edition by Ken C Pohlmann McGraw Hill Inc 1995 Filters always have some ripple For zero ripple filters this is in the udB to pdB region dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Clocking Internal clock The sample clock quality significantly determines the output performance of an ADC The highest quality clocks that are available are crystals so we use these In Master mode the dCS 900 amp 902 use one of two on board voltage controlled crystal oscillators VCXOs as clock sources one for 48 kS s related outputs and one for 44 1 kS s related outputs When an external clock is applied for Slave operation the internal VCXO is synchronised to this by a phase locked loop PLL The PLL is of a special narrow bandwidth type that provides a high degree of clock cleaning but even so signal quality may degrade if particularly poor slave clocks are used A consequence of the narrow bandwidth is that it takes quite a long time for the PLL to lock to a new clock frequency of the order of 2 seconds The PLL uses DSP assistance to keep this time acceptable Accuracy when shipped 10 ppm Long Term Stability 10 ppm year at room temp Temperature Stability 15 ppm over operating temperature range dCS
53. preferred dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Six Channel Set Up Sync ed to Master Clock Word Clock E i d 3 dCS 992 8 moresesta co k dCS 900 902 MANS FUSE AT ON OFF To digital recorder dCS 900 902 MA FUSE AT ON OF z Bee e Z A a From analogue sources CH5 amp 6 Figure 8 Six Channel Set Up Sync ed to Master Clock Word Clock Set the dCS 992 Master Clock to the sample rate you wish to record at and set the recorder to slave to it For all 3 ADC s set A SL Autoslave to On and select a filter If you are recording less than 24 bit words set Word Length as required and set Noise Shaping to Auto The Master Clock helps reduce jitter This arrangement will work with one two or more ADC s You can record from the SDIF 2 output or one of the SPDIF outputs if preferred dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Operating Several Units on One Remo
54. red by specifying the country of use It can be updated later by your dealer if necessary Video Frequency VCXOs We can fit additional video frequency VCXOs enabling frequencies such as 44 056 kS s and 47 952 kS s These must be fitted at dCS to allow full checking P3D DSD Pro and Other Formats We can fit larger FPGAs to allow P3D DSD Pro and other formats This has to be done at dCs Ordering Options For A New Unit To order any option just tell us dCS 900 for use in lt country gt with options or dCS 902 for use in lt country gt with options IMPORTANT Always specify the intended country of operation otherwise we will assume that country of delivery is the same as country of operation Having Your Options Changed dCS support modifications updates and option changes to supplied dCS 900 amp 902 units If you are in any doubt please contact your Distributor or dCs In general these will be carried out at dCS because we have extensive test facilities and can verify the changes IMPORTANT Please do not attempt the changes yourself The unit s performance and p ges y reliability may be impaired and the warranty will be invalidated dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCS Ltd 12 June 2000 Manual part no DOC0029021E1 Page 55 Document No OS MA D0002 902 1E1 Contact dcs on 44 1799 531 999 email to more desltd co uk inside the UK replace 44 with 0
55. red to as a D A Converter Digital to Digital Converter Sometimes referred to as a D D Converter dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Full Contents Rroductkeatutee dest dE ENEE ENNEN dE AEN NEEN Ae 3 Formats 3 Syncing 3 Functions 3 Test Generator 3 Ease of Use 3 CONTENTS snekret EENS EE 4 About this Manual 5 Warranty 5 Using Your dCS 900 902 For The First Time rrnnnnvnnnnnnnvnnnnnnnvnnnnnnnvnnnnnnnvenennn 6 Product Overview 6 What s in the Box 6 Mains Voltages 6 Installing Unit in a Rack 6 Getting Started 8 The Hardware Controls and Connectors rrnranvrrrnnnnvnvnnnnnnnvennnnnnvennnnnnrennnnr 10 Rear Panel 10 Balanced Analogue Inputs 3 pin XLR female 2 off 10 Input Level Adjustment trimmers 10 Reference In 3 pin XLR female 10 AES C Reference Digital Output 3 pin XLR male 10 AES A amp B Digital Outputs 3 pin XLR male 2 off 10 SDIF 2 CH1 CH2 Data BNC 2 off 10 SDIF 2 Clk In BNC 10 SDIF 2 Clk Out BNC 10 SPDIF Outputs RCA Phono amp Toslink optical 10 Remote In amp Out 9 pin D type male 2 off 11 Mains Supply 3 pin IEC CEE22 11 Additional Information 11 Digital Data Formats 11 Front Panel 12 Sample Rate 12 Multiplier 12 Mute 12 Word Length 13 Noise Shaping 13 Overload Level 13 Overload Indicator Overload LED 14 14 Master Slave Menu Down 14 Output Format 15 Mode Display 15 Sample Rate Display 16 The
56. ristics The characteristic is shown briefly on the main display Auto Unit sets noise shaping automatically depending on word length 24 bits no noise shaping 20 to 23 bits 17 order noise shaping 16 to 19 bits 3 order noise shaping Off No noise shaping Let 1 order noise shaping 3rd 3 order noise shaping 9th 9 order noise shaping The noise shaping LED above the button lights when the setting is other than Auto Overload Level Menu Step The Overload Level button is dual function on its own blue type on the front panel it sets the level at which overloads are detected by the unit With the other menu buttons MMG type on the front panel it is the menu BEN button Overload detection is normally set to full scale The detection level may be reduced in 0 1dB steps down to 3dBO by pressing the Overload Level button repeatedly or holding it down The set level is shown on the display for a few seconds The overload level LED above the button lights when the setting is other than full scale 0 0dBO For Menu operation as the GE button see the section The Software The Menu on page 18 dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Overload Indicator Overload LED Master Slave This overload LED lights for a few seconds when the set overload level is exceeded by a signal peak The detection circuitry monitors both input and digital filter
57. rnnvrrrrrnnrnr 36 Table 4 AES EBU i o specifications cccceeeeeeeeeeeeeeeeeeeeeeeeseeeesaeeneeeeeeaees 39 Table 5 SDIF 2 i o specifications cece ceeeeceeececeeeeeeeeeeeeeeeeeeeeeseaeeeseaeeneneeenaees 39 Table 6 SPDIF electrical output specifications rannrnnonrrnrnr vnr nrnnnnnnnnnnnnn 39 Table 7 SPDIF optical output specifications rrrnnrvrrronnvrrrrrnnvvrrrrnnrnrrrrnnnn 40 Table 8 Remote Control Interface Details 40 Table 9 Analogue XLR Interface Details 41 Table 10 SDIF 2 Message Table mrnrrnnnnrnnnnnvnnonrvnnnrrvnnnrnnennnnrrrrennnrnnsnnnnrennen 47 Table 11 Dither and Noise Shaping Noise Powers s sseesseeeseeeseseresssernees 51 Table 12 Internal Error Codes 58 Table 13 System Error Codes nenn 59 Table 14 dC Phone Number 61 Figures Figure 1 Recording with a dCS 900 007 8 Figure 2 Reor Panel cece tere eds vere EE A oad EEE A AEEA den 10 Figure g Front Panel osr eie a A E a EEE AT R Aa 12 Figure 4 Menu Sequence marsvnnnnvvnnnrrnannvnnannvenenrennnrnnannvnnennennsrresnnrnssnnnenenvenenn 19 Figure 5 Six Channel Set Up Sync ed to AES Reference n 24 Figure 6 Six Channel Set Up Sync ed to Master Clock AE 25 Figure 7 Six Channel Set Up Sync ed to Word Clock rrnrrnnnrrnnnnrrnnnnrnnrnrnnenr 26 Figure 8 Six Channel Set Up Sync ed to Master Clock Word Clock 27 Figure 9 Multi unit Remote Dais
58. s more dcsltd co uk Our web site is http Www dcsltd co uk Other Information dCS produce technical notes from time to time on issues related to ADCs If you are interested in these please do not hesitate to contact us dCS 900E 902E User Manual dCs Ltd Manual for Software Versions 1 3x to 1 5x 12 June 2000 INDEXES AND SOFTWARE VERSION NUMBERS This manual is for software versions 1 3x to1 5x v1 3x changes Word Clock amp AES Reference synchronisation improved v1 5x changes 904 related enhancements and hardware harmonisation v1 5x versions differ only in a few minor bug fixes Definitions of Units dB dBo dBu dBV KS s ADC DAC DDC A relative level in decibels The context should state the reference level Level in decibels referred to a full scale sine wave in a sampled system So 0 dB0 is full scale Level in decibels referred to a 0 775V rms sine wave with no external loading u unloaded The level of 0 775V is derived from the older dBm for which the reference level is 1mW of signal power into a 600Q termination from an output with 600 source impedance Level in decibels referred to a 1 0V rms sine wave with no external loading Sample rate in kilo samples per second This replaces kHz which is technically incorrect when referring to sample rates Analogue to Digital Converter Sometimes referred to as an A D Converter Digital to Analogue Converter Sometimes refer
59. s are quite insensitive to overloads Such equipment may include a sensitivity setting where an overload is only flagged when a number of consecutive digital words saturate typically 1 2 4 or 8 consecutive samples There is some justification for this single saturation events are not always audible The dCS 900 902 flags their presence it is up to the recording engineer to decide what to do about it dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 dCS SUPPORT wish If you wish your unit did something it does not or that this manual told you something it does not or that we made something we currently do not tell us If we can fix it with software or a manual reprint and we do so we will update your unit free of charge If we do decide to make the thing we will discuss with you how you would like it to operate We value our customers and we want to make products that do what you want If You Need More Help Contact dCS Our office hours are 8 00 am to about 7 00 pm Monday to Friday UK time UTC in summer or UTC 1hr in winter Contact us by phone or fax on Inside the UK Outside the UK Telephone 01799 531 999 44 1799 531 999 Fax 01799 531 681 44 1799 531 681 Table 14 dCS Phone Numbers You can write to us at dCs Ltd Mull House Great Chesterford Court Great Chesterford Saffron Walden CB10 1PF UK Our E Mail addres
60. set other functions Alternatively if left the menu will just time out keeping the last settings At power up the tone generator is set to 18dBO 1kHz and turned Off Runs a display self test routine When successfully completed the unit displays Pass and returns to normal operation Otherwise an error message Err xy is displayed please refer to Error Codes and Messages on page 58 for more specific information Disables the 7 segment LED display When set to Off the display turns off 4 seconds after the last button press A dot in the lower right hand corner of the display remains lit to indicate that the display has been deliberately blanked The display springs back into life temporarily if the menu is used subsequently Error or warning messages are displayed regardless of this setting dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCS Ltd 12 June 2000 Heat Displays the internal temperature of the unit Press EI to toggle between Fahrenheit and Celsius Phone dCS telephone number scrolls across the display Part The control board part number version scrolls along the display S No The control board serial number scrolls along the display You will need to tell us this number if you call us for help RS232 Displays and allows access to the unit s RS 232 identity code an address between 0 and 99 This is used by the remote control software to send specific messages to specifi
61. t it to something different You can customise your unit in this way Information only items are displayed for a time then the display reverts to normal Menu buttons are indicated by white text on the front panel There are for otherwise Overload Level otherwise Master Slave otherwise Output Format dCS 902 only Entering the Menu The Menu is entered by holding down the Bly button and then pressing the button once The display will show Func You are now in the menu and the menu buttons now have their alternate meanings Moving through the Menu Press the Step button again to step through the Menu items listed below When you reach the required item press the Si button to change its setting This either toggles the previous state or causes an information function to read out or enters a lower level as in the Tone generator for example If you have entered a lower level pressing Gly steps through its options When you reach the one you want press Si and then use the M or PN buttons to increase or decrease a value such as Level or Frequency on the Tone generator If no changes are made in 4 seconds the unit exits the Menu When one item has been set press the S button again if you wish to continue cycling through the Menu There is a knack in doing this easily once it has been gained it becomes very easy to use the functions it accesses dCS 900E 902E User Manual Manual for Software Vers
62. te Chain dCS 900 902 5 IN I LE The Politically Correct Computer Co if Ce Sen Sg COM PORT eS S 148 av OSE ERR i H ji B E HF S Si il et ji l Figure 9 Multi unit Remote Daisy Chain The PC can control several dCS units up to about 5 of different types on each daisy chain To make them individually addressable each unit needs its RS 232 address to be different They can then be identified and grouped in the remote window See Remote In amp Out on page 11 for cable details dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Recording Dual AES on a 4 Track Recorder From analogue source dCS 902 Sensitivity Digital Recorder INPUTS Gi Gi Gi Gi KC DE md md m BR 50 Ko Figure 10 Recording Dual AES on a 4 Track Recorder ES oGzJe sch Timecode Extension Set
63. the dCS 902 to the sample rate you wish to record at 88 2 or 96kS s and set the Output Format to 2 Set Ref In to Int and select a Filter If you are recording less than 24 bit words set Word Length as required and set Noise Shaping to Auto Replay the tape through a Dual AES capable DAC such as dCS 952 dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 dCS 900 902 TECHNICAL INFORMATION Anti Alias Filtering 3 The dCS 900 amp 902 offer a choice of 4 anti alias filters on most sample rates These filters affect the ultrasonic part of the spectrum 20 kHz upwards The unit is an ADC with an output data rate set by the interface standard used The bandwidth of the input stages and oversampling converter used is high and so any signals that that are in the input signal up to a MHz or so will be aliased back into the output signal if they are not removed by filtering The demands on this anti alias filter can be quite severe at the lower normal sample rates it must pass signals in the audio band 0 20 kHz unimpaired but it must prevent aliasing about Fs 2 This can result in a very sharp filter and it is an unavoidable mathematical result that sharp filters have a poor ringing transient response One effect of the ringing is to spread the energy in a transient over a significant period of time it can be up to 1 ms This seems to affect the stereo image that the ear
64. tions Changed Hardware Service amp Maintenance User Changeable Parts Software Installing New Software Hardware Update or Calibration Safety and Electrical Safety Error Codes and Messages Internal Device Error Codes System Messages and Error Codes Trouble Shooting Your System The unit fails to power up The audio output is low or absent The level trimmers on the rear panel do not change the input level The unit slaves to Word Clock but not AES EBU The Left and Right channels are swapped One output channel is low or absent Clicks or crackles occur on the outputs dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCS Ltd 12 June 2000 Periodic clicks occur in the recording 60 The unit fails to slave to a Master Clock 60 The Overload indicator will not go out 60 External meter does not show overload dCS 900 902 does 60 ACS SUP e GE 61 wish 61 If You Need More Help 61 Other Information 61 Indexes and Software Version Numbers rrrnnnnnnnavnnnnnnannnnnnnnvnnnnenannnnnnnnnennenn 62 Definitions of Units 62 Full Contents 63 Tables 66 Figures 66 Keywords and Phrases 67 dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x des Ltd 12 June 2000 Tables Table 1 Reference Clock and Sample Hates sre 15 Table 2 Output Data format indication higher sample rates rrnrrronnrnnrnrnr 15 Table 3 Noise Shaper Gain by Order and Sample Rate rrrrnnrrrrr
65. urn A SL On and select a filter For all ADC s if you are recording less than 24 bit words set Word Length as required and set Noise Shaping to Auto The units self align quite accurately see the section Sample Alignment on page 32 onwards This arrangement will work with one two or more ADC s the top one must be set to Int You can record from the SDIF 2 output or one of the SPDIF outputs if preferred dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 Six Channel Set Up Sync ed to Master Clock AES dCS 992 OOOO Oo 2820 08 moreedest coui AESEBU Outputs To digital recorder From analogue sources Figure 6 Six Channel Set Up Sync ed to Master Clock AES Set the dCS 992 Master Clock to the sample rate you wish to record at and set the recorder to slave to it For all 3 ADC s set A SL Autoslave to On and select a filter If you are recording less than 24 bit words set Word Length as required and set Noise Shaping to Auto For the ADC s processing CH1
66. web site www dcsltd co uk dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 MAINTENANCE AND SUPPORT Hardware Service amp Maintenance dCS audio products are designed not to need regular maintenance and contain no user serviceable parts there are no moving parts there are no short life or wear out parts used the units have no holes through which liquids or contamination can normally enter no dust deposits build up to degrade performance All parts are replaceable or upgradeable by dCS for a period of at least five years from the date you purchased your unit If your unit is damaged in some way please contact your Distributor or dCs User Changeable Parts IMPORTANT There are no user serviceable parts inside the case Routine maintenance is not necessary and repairs are generally carried out by dCS since this allows us to thoroughly verify the results before shipment There is a mains fuse in the mains socket accessible from the outside of the unit This may be changed by the user The current consumption of the unit is very low 150 mA at 110 V so it only blows if there is a fault usually if the unit is set to its low voltage setting 100 120V but has been plugged into a high voltage mains 220 240V Usually no other damage is caused but if the fuse blows repeatedly on replacement some other damage will have been done and the unit must be returned to dCS
67. y Cham 28 Figure 10 Recording Dual AES on a 4 Track Recorder 29 Figure 11 Word Clock and AES3 outputs 96 KS S mannrenonvrnrnrrrnnnrrnnnnnnnrnnnnrnr 32 Figure 12 Word Clock and AES3 outputs 44 1 KS S unnrnnonrvnrnrrrnnnrrnnnnvnnorrnnenr 32 Figure 13 Word Clock in to Word Clock out 96 KS S cccesceessesteeeeeeeees 33 Figure 14 Word Clock in to Word Clock out 44 1 KS S rrrnrrnnvvrnrrrnrrrnrrnnrnrnenn 33 Figure 15 AES3 in to AES3 out 96 KS S ernnsnnvvvnnrnnvvrnrrnnvvrnrrnnrrrnrrrsrrnnrrrsrnnnene 34 Figure 16 AES3 in to AES3 out 44 1 KS S ce cceccceseeeeeeeseeeeeeesseeeenseeeaees 34 Figure 17 Word Clock in to AES3 out 96 KS S mnrnnrrrnrrnnrvvnrrnnrrrnrrrnrrrnrrrrrnnnenr 35 Figure 18 Word Clock in to AES3 out 44 1 KS S mnrrrnnnnnrrrnrrnnrvvnrrnnrrnnrrrnrnnnene 35 Figure 19 17 Order Noise Shapers implemented on dCS 003 37 Figure 20 3 Order Noise Shapers implemented on dCS 00 37 Figure 21 9 Order Noise Shapers implemented on dCS 90X c0csceeees 38 Figure 22 AES3 format at 48 kS s over 16 metres c cceeeceesseeeeeteeeeeteeeees 43 Figure 23 AES3 format at 48 kS s over 94 metres cccceeceeesteeeseeeeeeetees 43 Figure 24 AES3 format at 96 kS s over 16 metres cceceeeceeeeeeseeeeeeeees 44 Figure 25 AES3 format at 96 kS s over 94 metres rrnnannrnnonrnnnnrrnnnnrnnnnnnnrnnn 44 Figure 26 SDIF 2 PCM format at 96
68. y quite unreliable We recommend restricting 96 kS s cable runs to 20 m or less and using good cable near this length A running 1 2 00 V div BH lim 3 500 10 00 1 IN de 2 2 00 V div pos 4 000 10 00 1 1MQ de 1 0000 us 0 000 s 1 0000 us 200 ns div repetitive Trigger Mode Edge E f 15 35 y Figure 22 AES3 format at 48 kS s over 16 metres A running 1 1 00 V div BH lim 2 000 10 00 1 IN de HU 2 1 00 V div pos 2 000 10 00 1 1MQ de 2 5000 us 0 000 s 2 5000 us 500 ns div repetitive Trigger Mode Edge E f 15 35 y Figure 23 AES3 format at 48 kS s over 94 metres dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 AR running 1 2 00 V div BH lim 3 500 10 00 1 IN de 2 2 00 V div pos 4 000 10 00 1 IM de 1 0000 us 0 000 s 1 0000 us 200 ns div repetitive Trigger Mode Edge E f 15 35 Figure 24 AES3 format at 96 kS s over 16 metres AR running 1 1 00 V div BH lim 2 000 10 00 1 IN de 2 1 00 V div pos 2 000 10 00 1 IM de 1 0000 us 0 000 s 1 0000 us 200 ns div repetitive Trigger Mode Edge E f 15 35 Figure 25 AES3 format at 96 kS s over 94 metres dCS 900E 902E User Manual Manual for Software Versions 1 3x to 1 5x dCs Ltd 12 June 2000 SPDIF Message Handling The SPDIF interface sometimes known as the Consumer AES EBU interface

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