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IE-UM-00166-001 RFT646 User Manual

1. 100 0 a BEER Yny Pare KE PE SE EEE me Pega ey yg pre Beware ey ET Fag PE PPEP i A AN 150 0 y em y 180 0 myw MET wheres TE mn were i hM baner ore carl i Poro Re ate ea red y e a 8 R RR Uo Diff h1 Chz Phase Diff Ch1 Ch Phase 5 81 dB e99 54 5 83 dB 299 46 Figure 30 Displaying options Meter left or Scope right IE UM 00166 001 RF 1646 User Manual odt 32 51 i Radar Rf Testset RFT646 Edition Date 25 Nov 09 5 Near Firo Scan RFT646 ann 3D Scan Kit 5 1 Introduction to Near Field Scan for 3D PSR Radar This chapter describes the use of the RASS S Radar RF Testset in order to perform near field scan measurements on 3D PSR radar systems It explains a user how to use the tool to measure the near field amplitude and phase distribution calculate the far field pattern and get the phase adjustments necessary to improve and or tilt the vertical diagram of the PSR 3D long range air defense radar The near field scanning tools allow a trained user to perform the necessary measurements to calculate and obtain the VPD from a near field scan in a short time frame The Tune function is available to focus on improving the side lobe levels for the negative elevation angles in order to avoid ground reflections and to reduce the interference for the close environment Another option is to minimize the notches in the main beam In both cases the result of this calculation is a phase
2. Cursor Readout Amplitude 74 5 Phase 38 1 Time domain curve 8 0E 0 j A 4 0E 0 I Ur 1 J 2 0E 0 D 0E 0 0 0E 0 ll em MELE vag s Figure 10 Noise level 20 0E 6 curt Boe OOS cur2 Eo ne s Je Filter On t 1 I 40 0E 6 60 0E 6 80 0E 6 Time velocity Factor ai ce Distance 91 50 4 Now the DUT or the transmission chain can be inserted as shown in figure 6 When the DUT is connected provides the correct result gt VectorNetworkA nalyser vi CE DPR Sweeping r Amplitude 17 1 18 0 19 0 20 0 21 0 22 0 23 0 240 24 8 1000 0 1020 0 MEG H AN REY amp I 1040 0 Attenuation 1120 Tr 58 60 1000 0 ME DB VENGAR I 1020 0 I 1040 0 I 1 1 1080 0 1100 0 1120 0 ee Sweep Parameters Start frequency 1000 000 Stop frequency 11128 000 Step frequency di y Cursor Readout Amplitude 20 3 Phase 57 0 Time domain curve 10 0E 3 8 0E 3 J 6 0E 3 4 0E 3 2 0E 3 0 0E 0 0 0E 0 I ase a Ip UU r To Spreadsheet Be et PT ST RT TT SVT z r Fy Li Filter On J y2 d 1 20 DE 6 40 0E 6 60 DE 6 80 0E 6 Cur I porto OAS Time velocity Factor Cur2 6O 0E 6 Bo oE46 m BG Distance 0 66 Figure 11 VNA transmission measurement result The frequency sweep repeats continuously until the
3. Tips amp tricks Make a measurement in the center column and take reference unplug the cable and read the dynamic range gt 30dB When measuring an additional channel do not take reference again or you will loose the relationship between the two measurements 2 3 VNA Reflection Measurement 2 3 1 Getting Started The VNA reflection setup will make use of an extra coupler This directional coupler will isolate the energy that is reflected by a DUT or a transmission chain The VNA software can derive by both amplitude and phase measurement the physical place and strength of a reflection in a transmission chain The example in section 2 3 3 will show you how to read the results The basic setup of the VNA reflection measurement is shown in figure 13 Please note that the attenuators can be removed depending on the signal level of the return signal In principle the reflected power is measured using this setup The main advantage is the fact that only one side of the device under test must be connected Reflected power of a part of the chain is measured by setting cursors in the time domain filter IE UM 00166 001 RF 1646 User Manual odt 20 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 0 5m BNC c DUT 10dB Coupler ZFDC 10 5 Figure 13 RFT646 connections for VNA reflection measurement Ea When the connections are made load the Vector Network Analysis tool from the el VNA button in the RASS S toolbo
4. Figure 18 Time domain curve selection with cursors This graph shows the isolation of the biggest reflection that occurred due to the cabling It was the transition from RG223 to RG216 coax cable with a BNC straight jack in between IE UM 00166 001 RF 1646 User Manual odt 23 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 Amplitude Attenuation 10 0 k 0 0 10 0 Ae 20 0 30 0 40 0 50 0 60 0 l l l l l I l l l l 500 0 250 0 900 0 950 0 1000 0 1050 0 1100 0 1150 0 1200 0 1250 0 1300 0 IE 4 88 Alt Euro iiz e fs e2 DO Jal WE HEN Eur Bes se 5 72 m lli Figure 19 Attenuation of selected reflection The amount of reflection between the cursors selected reflection is shown in the Amplitude parameter This leads to the SWR of the cable connection using the next formula or a conversion table which is based upon this formula 107 1 10 1 reflection coefficient VSWR Where x is the relative amount of reflection in dB shown in the Amplitude parameter In case the relative amount of reflection is 15 7dB the reflection coefficient VSWR is 1 393 IE UM 00166 001 RF 1646 User Manual odt 24 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 3 Far FIELD SIMULATION OF ANTENNA 3 1 Getting Started A specific software tool allows to investigate the far field behavior of the M SSR antenna both for vertical and horizontal directions The program ca
5. 1000 0 1020 0 1040 0 1060 0 1080 0 1100 0 1120 0 1140 0 V R E me ME vag gm cur 2 B9 7 0 m JE H Distance 40 67 ll JPY 4 Frequency response curve IFFT Time domain response curve Figure 5 Overview of mathematical computations 2 2 VNA Transmission Measurement 2 2 1 Getting Started The VNA software is able to deliver information of both amplitude and phase deviation of a device under test As explained before the measurement is performed by comparing the measurement channel with a reference channel receiving the stimulus The RFT646 contains an internal reference channel so you will only need to connect the measurement channel The connections for the VNA transmission measurement are straight forward The RFT646 has a coupler and internal RF switch so that the reference signal derived from the Tx output is fed through internally The only external connections to be made are the ones that are indicated in the connection diagram below The 10 dB attenuators are default in this setup they do not only protect the RFT646 s receiver but they also increase the measuring accuracy by improving the VSWR Further more two RG223 2m cables are used to connect the device under test For the reference measurement we connect the cables together with a barrel as indicated in the figure below the barrel is later on replaced by the DUT IE UM 00166 001 RF 1646 User Manual odt 14 51 Radar R
6. dBm 9 1 I I I I I Phase 5 0 10 0 15 0 20 0 25 0 ll ey XI None Window I Env 2 100 0 00 50 0 100 0 Settings r CW Power Calibrate Holdoff pus 1000 og we sy 180 0 20 1 3 Max Amp dB MHz A bso te 0 00 n Averaging i iy dB 20 Signal Frequency Diff Chi Ch2 Phase deg R itve 0 0 e Sampl 61 3 Figure 24 PVV Software Using the PVV Software Set the Signal frequency control to the Rf frequency of the signal to be measured This frequency setting is used to down convert the RF signal to a 2 MHz baseband signal The baseband signal is then digitised at a 16 MHZ rate Each trigger on channel 2 results in 512 samples per channel At a sample rate of 16 MHz a period of 32 microseconds is covered on each trigger The last 512 blocks of 512 samples two channels are stored in memory and every one of those 512 blocks can be recalled and displayed at all times To achieve a higher accuracy a measurement can be averaged over several consecutive triggers The number of averages can be set using the Averaging Samples control Three trigger modes are available o External uses a digital trigger connected using the external trigger cable to the digital output connector on the RFT646 back panel Use this mode in case you have a trigger available for the RF pulses used for the measurement o Analog in this mod
7. measuring interface is shifted towards the position where the cables are switched and the measuring path is de embed from the measurement Like in the relative calibration the offsets in phase and amplitude are shown in their respective indicators below the calibration buttons Notice that these amplitude and phase offsets are not used to correct the displaying of the two signals They are only used in the calculation of the phase and amplitude difference between the two channels Both calibration procedures take into account the same averaging factor as used for the measurements Once a calibration procedure is accomplished successfully the Amplitude and Phase indicator on IE UM 00166 001 RF 1646 User Manual odt 31 91 i Radar Rf Testset RFT646 Edition Date 25 Nov 09 the right hand side of the window become active These indicators show the difference in amplitude and phase between the two channels taken into account the results from the calibration procedure 7 There are two displaying options selector in the Amplitude amp Phase section a meter display and a scope display The meter display shows the amplitude and phase separately and the scope display shows the result as one vector Both options also include a digital display It is possible to choose between different scales Amplitude amp Phase Amplitude amp Phase Meter v 10 dB Scope v Diff Chi Che 10 0 dB j div
8. 001 RF 1646 User Manual odt 43 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 positions from a previously saved file Default location of the slider positions file is in the NETWORK TAPERING subdirectory of the active campaign folder 4 Once the position file is loaded the mechanical position of the phase adjusters in mm is displayed in the Phase Adjustment graph Phase Adjustment Length mm _ mm 255 7 240 220 200 ee us si Readout 7 00 an Relative L Figure 43 Phase adjustment graph 5 It is now necessary to select the region and suppression of the sidelobes as required The two vertical cursors in the Antenna Diagram graph allow to select the elevation part for which the sidelobes need to be reduced as shown in figure 42 The horizontal cursor allows to select the maximum sidelobe level allowed Once the cursors are selected click the pray button to start the optimisation The Antenna Diagram graph will show the original diagram in reference together with the antenna diagram as a result of the tapering optimization Optimization is performed by random changing the phase tapering and retain those changes that have an improvement for the requested elevation section Figure 44 shows the phase changes required versus the row number to remove the first sidelobe and reduce it below 30dB Phase Adjustment Phase deg 90 r 60 40 20 Ht eae ed ai 20 7 60 9
9. 001 RFT646 User Manual odt 39 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 gt View VNA Scan vi Original YNA Data Reference Tapering File reference YNA 2001 2004 15 59 33 Amplitude oto te I 1 1 1 I 1 5 0 100 150 200 20 300 350 400 450 MGE B a Euro f 00 _ degfa 18 JE 2 MF vg meis en en Sl 9 IE ta 8 FDA ey Figure 38 View VNA Scan Reference file loaded The reference file is loaded and the samples used as a calibration are indicated as black dots 4 The result of the deconvolution is shown in the Tapering tab The of rows of the antenna is listed at the top If the encoder calibration was performed correctly during the measurement the software will set the number of rows automatically IE UM 00166 001 RF 1646 User Manual odt 40 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 5 The Amplitude and Phase graph displays the result after calculating out the probe calibration as loaded in the reference As a result of the deconvolution the energy picked up with the scan board is focused to the corresponding row number providing a measured tapering table in phase and amplitude If there are any broken transmitters in the array they can be detected easily on this graph Two cursors are available to indicate the position of row 2 left cursor and the position of the second last row right cursor at rows 1 These cursor a
10. 09 2 1 3 Frequency Domain to Time Domain and Vice Versa In order to measure all these different parameters of a DUT the VNA should be able to produce signals with a variety of frequencies to inject into the DUT By injecting different frequencies and analysing the transmitted signals of the DUT a frequency response curve can be derived The frequency response curve can then be transformed to a time domain curve by calculating the Inverse FFT IFFT The most interesting feature of this mathematical approach is that the time domain curve can easily be transformed to a signal amplitude in function of distance or time By limiting this curve to a section in distance or time the frequency response curve can be recalculated Doing so the user is able to evaluate the frequency response of a specific part in the transmission chain for instance the reflection of a rotary joint The description of the mathematical formulas can be found in the LabVIEW manual Amplitude Attenuation A 5 0 0 0 60 0 gt i U 1 1 1 U 1 U 1000 0 1020 0 1040 0 1060 0 1080 0 1100 0 1120 0 1140 0 es AF fro ons ma Varen gn fori ewe OC JE ERR d Time domain srl Phase 1 Phase A Filter On y 250 0E 3 r 200 0E 3 150 0E 3 100 0E 3 50 0E 3 51 0 0E 0 1 1 i i 0 0E 0 25 0E 0 50 0E 0 75 0E 0 100 0E 0 125 06 iJ ann pS Cur 1 poro JOB Time velocity factor 200 1 U i U U 1 1
11. 3 VNA Reflection Me sur ment Lu nussumsmnasnsgmsrmndasdrinsemisrapnddsnmieksdadanaenieenedd 20 AG COLIN 510 EEE EN 20 2 3 2 Performing a VNA Reflection Measurement rrrnnnnnnnnnrnnannnnnnnnnvnnnrnnnnennnnrnnnnrennennernnannerneennsnner 21 2 HO lO read Me Te ul S eruera CARO I Ry teste Y EGO TYWOD OY NOIL AR RACE 22 2 3 3 1 Measurement Exampl amp ee su a a NODD CYR cao SnHO NG OG iy SO Do GM Tw 22 2 3 3 2 Calculate the VSWR of a Specific Part of the Transmission Chain ee iu re i ui uun 23 3 FAR FIELD SIMULATION OF NTENNA ananauvaunnnnnnnunnnnnnnnnnunnunnnnnnnunnunnnnunnunnnnnnnnununvnunnnnnnnnne 25 SL SENG SEE hvem 25 3 2 Calculating the Far Field Pattern srxrnnnnnnnnnnvnnnnnnnnnnnnnnnennnnnnnnnnnnnnnnnnnnnernnnnnnnnnnrnnnnnnnnnennnnennnnnnnnnnen 25 4 P SE VERVE Eee 28 Er 0 SE LOG EE EN EE EN 28 AZ SING the PVY SIN 29 5 NEAR FIELD Scan RF T646 and 3D Scan KiT naunaunannnnnunnunnnnnnnunannnnnnunununnnannnnnnunnnnnnn 33 5 1 Introduction to Near Field Scan for 3D PSR Radar rrnnnnnnennnvnnnnnnnnnnnvnnnnnnnnnnnnnnnnnnennnennnnnnnnennnnne 33 5 2 3D Scan Hardware SE UP sassanidene 33 5 3 Near Field Scan Measurement Software ranxrnnannnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnennnnnnnnnnnnnnnennnnnnnnnnunnnnnnnnee 34 IE UM 00166 001 RFT646 User Manual odt 4 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 5 3 1 Getting SE o EE ene eee ee eee ee eee eee 34 5 3 2 Basic Softwa
12. M stop button is hit it is probable that a measurement sweep was already taking place The next sweep IE UM 00166 001 RFT646 User Manual odt 17 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 5 To save the measurement click the og curves button A pop up dialog appears The user can create a new logfile or open an existing logfile Add logging will add the graphs data and the data entered in the Info field to the requested logfile IE UM 00166 001 RF 1646 User Manual odt 18 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 2 2 3 Example 1 Measuring the loss of a transmission chain This paragraph shows an example of a transmission measurement The DUT of the example is a transmission chain containing two 4m BNC RG223 cables connected with a straight BNC barrel total of 8m Replace the BNC barrel in figure 6 with the two 4m cables when the reference measurement is done The transfer function is presented in the frequency domain like a Bode diagram gt VectorNetworkAnalyser vi a ICTS a m Amplitude Attenuation 5 0 0 0 L rSweep Parameters Start frequency 411000 000 Stop frequency 28 000 Step frequency ap 60 0 EF YR 1000 0 1020 0 1040 0 1060 0 1080 0 1100 0 1120 0 1140 0 ursor Readou ME i Ar Euro Boo on Ea e2 JE Jf MN amplitude Dr Eur fi300 0 E5 72 JOE 3 4 Phase i 200 150
13. Rf Testset RFT646 Edition Date 25 Nov 09 GLOSSARY OF TERMS CFF Column Fault Finding measurement CW Continuous wave dB Decibel DUT Device Under Test FFT Fast Fourier Transform IE Intersoft Electronics IF Intermediate Freguency IFFT Inverse FFT LVA Large Vertical Aperture antenna PSR Primary Surveillance Radar PVV Pulse Vector Voltmeter Radar Radio Detection And Ranging RASS S Radar Analysis Support Systems Site measurements RF Radio Freguency RX Receiver SSR Secondary Surveillance Radar TX Transmitter VNA Vector Network Analyser VPD Vertical Polar Diagram VSWR Voltage Standing Wave Ratio ratio of maximum voltage to minimum voltage on a line IE UM 00166 001 RF 1646 User Manual odt 9 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 1 TECHNICAL Manual RF T646 1 1 General Introduction The RFT646 is a versatile dual channel L S band Tx Rx measuring unit capable of generating fixed or swept frequency RF test signals in the 700 3500 MHz range Basically it consists of two phase controlled receivers with digital intermediate frequency measurement channels Additionally two transmitter channels can provide arbitrary test pulses A USB interface is used for real time communication between the DSP controlling the RF units and the user interface software running on the host computer The functionality of the unit as for all RASS
14. f fee r e EG n n n n D o ro r Po ro Jno co ro Jno ry Jno ro n IN r 1 Bad 18 STB 00 00 M ao a a a a a a a a a a 50 0 55 0 60 0 65 0 70 07 75 07 80 0 85 07 90 2 0 3 0 mo 60 80 90 10 0 110 a o J o 7 no o o a CES Fel FU FU PES RE Fu NINIS ro no N no HE banet bas bad bedt bg jc ola a a a a a 0 1 1 I I l I I 1 I U I I Ll 180 0 150 0 125 0 100 0 75 0 50 0 25 0 00 25 0 50 0 75 0 100 0 125 0 150 0 180 0 FELE Eras eln gt e N N il Ead Fd ed pd om a ao ao a o e U r Parameters degree dBs a Dipole Element separation 0 22500 m 90 0 30 0 nel Step g0 10 C Qabs Frequency 1090 00 MHz o cn 23 0 jn EE noise 0 00 de Phase noise sooo o ntenna bending 0 i omni reflector 60 0 3 a Beamwidth 2 70 Offset 0 00 dB Figure 21 Antenna simulation example after loading a tapering file The data of the selected tapering file is shown in the spreadsheet form in the Tapering section of the software vi It is possible to save the loaded tapering file again using the El save Tapering button Saving the tapering table can be useful in those cases where the user detects a faulty dipole If that faulty dipole has a great influence on the resulting antenna diagram the data could be adjusted and saved as a corrected tapering file The tape
15. of each measurement then remove attenuation to increase signals but avoid saturation 2V IE UM 00166 001 RFT646 User Manual odt 48 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 6 3 Annex 3 3D Scan Reception Connection Diagram A Make sure to switch the Radar transmitter off Side View Encoder Signal Tape measure RJ45 cables RJ45 RJ45 couplers DB9 to RJ45 cables Insert 10dB of attenuation RFT Front Rf Beam Output Insert 10dB of attenuation pg o o Chi out ChZ in Digital Input Output co Operator USB Connection Power Connection with Computer Figure 49 3D Scan Reception connection diagram Un IE UM 00166 001 RFT646 User Manual odt 3 49 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 6 4 Annex 4 Configuration List RFT646 Check Qty Description Item List Radar Rf Testset O 1 Radar Rf Testset RFT646 O 1 Mains power cable O 1 USB cable A to B 3m RFT646 Accessories O 1 2m brown BNC cable O 1 2m red BNC cable O 1 2m blue BNC cable O 1 2m grey BNC cable O 1 0 5m red BNC cable O 1 0 5m blue BNC cable O 1 15pHD to 5 BNC m cable O 1 3DS External Trigger Cable O RFT Accessory Box O 3 BNC f to SMA m connector O 2 BNC f to N m connector O 3 BNC f straight adaptor DC 4GHz O 3 BNC T adaptor f f m O 2 N f straight adaptor O 2 10dB BNC Attenuator O 2 20dB BNC Attenuator 1 Directional coupler ZFDC 10 5 BNC O 1 Power splitter ZFRSC 42
16. pick up dipole or a sample of the stimulus signal generated by the RF T646 and measured internally via a coupler In both cases the Rx input is the measurement channel Once a reference is taken relative amplitude and phase are calculated for each signal window taken The cursors on the signal window allow to select the part of the signal used to calculate the amplitude and phase The signal sampling can be triggered in three ways e Timer This mode is used when the internal RF generator is used to provide the stimulus for the measurement e Analog In this case the sampling is triggered by the signal available on channel 2 Since channel 2 is the reference signal amplitude and phase are constant and therefore triggering is ensured The trigger sensitivity can be selected using the Level control e External The trigger is evoked by a digital trigger signal provided by the radar In this case the analog trigger capability is switched off When performing a scan using the surf board antenna first make sure the program is using the Surfboard Method For this measurement method in order to be able to measure the position at which a sample is taken the RF Testset is interfaced to an encoder By moving the measure tape the encoder provides a number of pulses corresponding to the displacement of the measurement antenna surf board antenna This way the position of the board is indicated The tool allows to calibrate the encoder position into a ro
17. probe in front of the column as shown in Annex 6 1 If the signal is too low to be measured then remove the 10dB attenuator at the Tx output to increase the injected power 3 Hold the antenna probe in position as stable as possible Each scan has to be performed in the IE UM 00166 001 RF 1646 User Manual odt 19 91 Radar Rf Testset RFT646 Edition Date 25 Nov 09 same way The more stable a measurement is performed the more repeatable the results will be A maximum deviation of 1cm is still acceptable 4 Select th first Element elect the column number you want to measure first y Click the lage button This will add the measured values of the last frequency sweep in the spreadsheet 5 Then select the column you want to scan next Repeat the procedure for all the other elements of the antenna 6 Now it s time to verify the measurement results In case you have doubt about a specific column measurement you can always repeat the measurement and if necessary replace the previous measurement value with the new result by entering the Element and clicking the Add button 7 Click the El saveTapering button to save the complete table and info data in the selected folder 8 A dialog box will pop up pointing by default to the Network Tapering directory of the active campaign folder 9 To interpret the measured results use the Radar Antenna Simulation software which is explained in section 3 Far Field Simulation of Antenna
18. required power range To allow the Rx and Tx frequency to be different both sections have their own synthesizer module This makes it possible to add a number of SSR functionalities such as transponder testing remote field monitor function etc IE UM 00166 001 RF 1646 User Manual odt 10 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 Digita Input Output Digital Attenuator m J2 Tx Oscillator 900MHz 3500MHz J7 Internal RF Receiver Module J1 15 I J437 J3 Rx RF Receiver Module J6 Figure 1 RFT646 Block Diagram Rx Oscillator 900MHz 3500MHz Sampling Module DSP Module USB Interface 1 3 2 Connectors 1 J1 External Transmitter a BNC connector b Frequency range 900MHz to 3500MHz programmable frequency synthesizer stabilised accuracy 100kHz c Frequency step size 125kHz d Max Tx power lt 10dBm e Modulation range 60dB 2 J2 Tx Identical to J1 3 J3 Rx a BNC connector b Frequency range 900MHz to 3500MHz c Linear sensitivity 20dBm to 80dBm d Log sensitivity 10dBm to 80dBm 4 J4 J5 Ch1 Ch2 Video Inputs a Analogue video inputs to acquisition system b BNC connectors 9 J6 J7 Ch1 Ch2 Analogue Outputs a Analogue video output from Rx b BNC connectors IE UM 00166 001 RF 1646 User Manual odt 11 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 2 Vector N
19. stopped with the stop button the slider under the display becomes active and the last 512 blocks of 512 samples can be displayed using this slider It is possible to zoom or pan on the display 5 With the envelope checkbox Env it is possible to switch between the signal as it is been sampled but down converted to 2 MHZ or the envelope of the baseband signal Signal display 0 ll preg D x i Window lw Env 2 7 Figure 26 Envelope function Because further processing of the measurements includes a FFT algorithm it may be opportune to insert a window function on top of the measured data A number of different windowing functions are available in the tool E None Hanning Hamming Triangle Blackman Exact Blackman Blackman Harris Flat Top Figure 27 Window functions The windowing function is applied only between the two cursors The different windows can be visualized by switching off the envelope option IE UM 00166 001 RF 1646 User Manual odt 30 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 I I I lus i 25 0 50 0 35 0 a g Bu Pa ll EY fh X Hamming bd Window Enw 2 Figure 28 Example of Hamming window 6 To use the Pulse Vector Voltmeter to its full potential a calibration of the tool must be built in There are two possible calibration procedures a Relative and an Absolute calibration To evoke one of the two calibration procedures push the appropria
20. very handy to work with in the field d Note The Radar Rf Testset has a large number and variety of electronic components inside Therefore we advise the user to allow the system a warm up time of a few minutes in case the maximum accuracy is reguired 2 1 2 Basic Concepts of Vector Network Analysis When dealing with low frequency devices such as transistors and opamps we usually consider a transfer function of a device as straight forward e F t Vout t Vin t in the time domain e F f Vout f Vin f in the frequency domain When dealing with RF or microwave energy we have to be more careful with these assumptions In fact this can be compared with light waves When passing energy to a device a part of this energy will be transmitted through the device and a part of the energy is reflected back into the source Stimulus DUT n Transmitted Reflected Figure 2 Principle of reflection This means that an RF device has two transfer functions e Transmission function F f Vtransmitted Vstimulus e Reflection function R f Vreflected Vstimulus IE UM 00166 001 RFT646 User Manual odt 12 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 From these functions several different parameters can be derived Table 1 Reflection and transmission parameters Reflection Transmission Input SWR Gain attenuation Return loss Isolation Input output Impedance Insertion phase Reflection Coeffic
21. 0 I I I 20 30 1 10 lg Readout 7 00 9 13 E nue Figure 44 Necessary phase changes to remove sidelobe The following figure shows the theoretical result in case these changes will be implemented IE UM 00166 001 RFT646 User Manual odt 44 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 6 Antenna Diagram New p Original I 1 1 I 1 1 1 40 0 30 0 20 0 10 0 0 0 10 0 20 0 30 0 40 0 50 0 uken IF mim BE Es ease EE K Figure 45 Tuned Antenna Diagram You can stop the adjustment process anytime you want by clicking the stop button The program will ask you to save the NEW positions of the slider as a result of the tuning This can also be done afterwards using the I save button The default path to save the slider positions is to the TAPERING su bdirectory It is possible to limit the number of phase adjusters to a selectable number Only that number of phase adjusters with the maximum change are selected in order of magnitude This can be selected in the sliders section Check the Limit checkbox and enter the number of phase adjusters to be used The influence on the antenna diagram is immediately shown When saving the slider file the slider positions that are required to change are changed in the slider file the other ones are left unchanged Do not forget to export the slider position file it contains the changes in textual format with the change
22. 0 05 if you like to draw more dots on the graph Amplitude Noise and Phase noise will add extra noise to the tapering table to check antenna pattern dependency on the tapering used Offset can be used to add the gain of the antenna in case you want to save the antenna pattern with its absolute gain 9 In case you have a tapering available as a tab separated file you can load it with the import Tapering File button This is useful in case you want to enter the manufacturers theoretical tapering The El save Tapering File button allows you to save the contents of the Antenna Tapering to a IE UM 00166 001 RF 1646 User Manual odt 42 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 spreadsheet file In case you want to make changes to the antenna tapering and compare the result with the original antenna diagram you Wr use the reference button to copy the antenna diagram to the graph as a reference The clear Reference button allows to remove the reference diagram from the graph 9 3 4 2 Tune the Vertical Diagram As a special option in case sliding line adjusters as selected by IE are installed in the Tx chain it is possible to tune the transmit pattern The Tune Tx Pattern function takes the measured antenna pattern and uses the current position of the sliding line phase adjusters to calculate a new possible solution for the phase tapering The goal is to minimize the Tx Power at a selectable elevation section below a select
23. 1 Frequency g 1295 00 MHz Step Size 0 20 deg au piat Element separation 10 01750 m amplitude noise 0 00 dB 27 000 0 775 12 595 TT Mechanical Tit 10 0 deg Phase noise 40 00 deg 28 000 n 426__ 14 295 Tx Pattern i Offset 40 00 dB Figure 46 Final tuned antenna pattern IE UM 00166 001 RF 1646 User Manual odt 46 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 6 ANNEXES 6 1 Annex 1 CFF Connection Diagram 10 babble nl Radar Rf Testset RFT646 IE Rotary Joint Chi Wn Analog Outputs Digital O O Input Output Ch1 out Ch2 in OD OD ER USB Connection Power Connection with Computer Figure 47 Column Fault Finding connection diagram cececeeeeeeeoeooeooeoeoeoeoeoeooeooeoeoeooeooeooeoeooeooeooeooeoeooeooeooooeoooooooeooooooooooo oeooeooooe IE UM 00166 001 RFT646 User Manual odt 47 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 6 2 Annex 2 3D Scan Transmission Connection Diagram A Avoid walking in the radiation field of the antenna Side View Encoder Signal Tape measure RJ45 cables RJ45 RJ45 couplers DB9 to RJ45 cables Insert 60dB of attenuation RFT Front RFT Back Insert 60dB of attenuation Analog Outputs o o ned ewes Chi out Ch2 in i J Operator USB Connection Power Connection with Computer Figure 48 3D Scan Transmission connection diagram Tip Use enough attenuation at the beginning
24. 100 50 0 50 100 150 200 1 1 I 1 I 1 I 1000 0 1020 0 1040 0 1060 0 1080 0 1100 0 1120 0 1140 0 EE l MHz PE Figure 12 VNA measurement result The transmission chain had a cable loss of 3 4dB which is acceptable for this type of cabling The average attenuation is calculated from cursor to cursor in the frequency domain So it is possible to determine the loss of the transmission line at 1030 MHz in particular 2 2 4 Example 2 Column Fault Finding measurement CFF In order to calculate the HPD far field behavior of an SSR antenna you can measure the transfer characteristics of the individual elements in certain row of the SSR antenna using the antenna probes This is done by scanning the elements in a sequence from the left to the right or vice versa You can also measure the VPD near field behavior by measuring the elements of a specific column This is done by scanning the elements in a sequence from the bottom to the top or vice versa The connections are identical as shown in figure 6 the only difference is the DUT itself Check Annex 6 1 for the full set up diagram The tapering is measured as follows 1 Follow the steps explained in section 2 2 to perform a transmission measurement 2 Check the position where the lowest power is expected This is probably at the end of the column line up horizontal scan or at the top of one column vertical scan Put the antenna
25. 200 0 1250 0 1300 0 E DD IE t A Euro li264 6 F3 62 JOE E mM r Cursor Readout AY gn Eur Bes ea t5 72 LJ Ma 8 1 rSweep Parameters Phase 83 6 Time domain curve I I I 10 0E 0 20 0E 0 30 0E 80 1 1 800 0 550 0 900 0 950 0 1000 0 1050 0 1100 0 1150 0 1200 0 1250 0 1300 0 AS i MHz I 280 F Curl B oe 0 JO B fm time velocity factor M MY Cur m e H Distance 0 66 Figure 16 Example measurement result In the frequency domain the software shows a 8 1 dB attenuation which means that about 10 of the energy is reflected The result 8 1dB attenuation is the average of the view in the frequency domain between the frequency cursors Changing the cursors in the time domain also changes the view in the frequency domain So the IE UM 00166 001 RFT646 User Manual odt 22 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 result of the calculation for the average attenuation is taking into account both the restrictions in frequency as in the time domain This allows you to isolate a reflection at a certain location The time domain curve is continuously updated Check the Filter On check box in the Time domain Curve field to enable the time domain filtering between the cursors only the section between the cursors will be sent through the IFFT You can see in the time domain window that the graph corresponds to the examp
26. AR ARDU DER EA a 10 1 1 AO MOV NON NN FUN Y NEF RFFRHEN HEN ERAEZ NF EEFFYFNRFAE RF AFR EWYTHYR NE TENT HNN 10 Meg TROY FOSS a 10 1 Hard w are DEP 10 Toek BDA EY RF E A EAR EEE 10 JE EG a a EE aai EEE O O Y Y YDD A GNAU OD GODA DG 11 2 VERNE 12 DMs MNS ONY FY EE HEFCE FFF EF FR RF E R A FYTH FFF FN EEF EAR ER E NR FY E 12 211 TOAN to V NA Gan dau iU GC nU UN ni RG NGR na FYR GR UAN FAR GG OG NS AR fS 12 2 1 2 Basic Concepts of Vector Network AnallySIS cccccceeccceeeeeceeeecaeeeeseeeeeseeeeseeeeeseeeesaueesaaeeeaaees 12 2 1 2 1 Transmission Parameters rrrnnrnanrnnrnannnnnnarnnnnnnrnnnnnnrnnnnnnnnnennsnnnnnasnannnernannnnnnuennnnenennnnennenene 13 21 22 RellecUotiPararhelBeT Sei cT Gw Cryd WYR AC GWN SYR e FN Ga RA MD 13 2 1 3 Frequency Domain to Time Domain and Vice Versa 99 eir HYLL LLYY Y YL L LLY Y LL RH NY FFR Y rrene 14 2 2 VNA Transmission Measurement arnnnnnnnnnunnnnnnannnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnennunnnennnnnnnnnnnnnnnnnnnnnn 14 2 2 Getting Stared EEE REF FE AA FE RF GY RY EF CYFN NY FFEFRIR 14 2 2 2 Performing a VNA Transmission Measurement 99 YYYY LY LEL ALL LLYR LLE RYFEL FLY FY LY FFY FE aN 15 2 2 3 Example 1 Measuring the loss of a transmission chain 9 eru LLY AWL YLA Y ALL YY LLY LY YY Ynn n yu 19 2 2 4 Example 2 Column Fault Finding measurement CFF rrrrnnnnnnnnnnnnnnnnnnnnnrnnnrnnnnennnnnennnsennnnnnenn 19 2
27. CROWN ennenen 35 Figure 33 SIGMA DIS DA rn 36 Figure 34 Amplitude and Phase window deselected rnrrnnunnannennannannennannnnnennannnnnnnnnnvnnnnnnnnnnnnnnnnennnnner 37 Figure 35 Vertical scan data while performing a near field SCanN r rnnnannnnnuunnnnnunnnnnnunnnnnnnnnnnnnnnnunnnnnnnur 37 Figure 36 View PSR F r Field STM ey vea 38 Figure 37 View VNA Scan software result checking the repeatability in the original data right 39 Figure 38 View VNA Scan Reference file loaded rrnurnnnnnnnnnnnnnnnnnnnnnnernnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnr 40 Figure 39 Placing the cursors on row 2 left and on the second last row right 41 Figure 40 Amplitude and phase tapering resull L LY LYYLLYYLLYNNLNYLLN ALANA ALL YLY YNN YL YNN Y Yna 41 Figwe 4T PSR far Nelda dia al aei Ne 42 Figure 42 Tune Tx Pattern SOU WAN Cosas cassie cae cxaivesausttnnsunaseeueia eat ncinduddansuxteeeas OA DAN YRRU TAU OS WM YAA ARNAU 43 Figure 43 Phase adjustment graph nurnnnnnnnunnnnnnnnnennannennennannennennnnnernannnnnnnnnnennnnnnnennnnnnnnnennnnnnnnnnnnnnnnnnnnnner 44 Figure 44 Necessary phase changes to remove sidelobe nrrrnrrvnnvannunnnnnnnnnnnnnnnennnnnannennennnnnrnnnnnrnennnnner 44 Figure 45 Tuned Antenna DIagralTl a isa iN Oa Gadd WDD RR Gn Gwd WA A SDO ANNA DWY NS 45 Figure 46 Final tuned antenna Patter nn ccccsccccccccnecensnscnnensnnecenenean
28. ETWORK NALYSIS 2 1 Theory 2 1 1 Introduction to VNA The Vector Network Analyser using the Radar Rf Testset further called VNA RFT is developed for measuring the frequency characteristics of RF single and dual ported devices The unit can measure both amplitude and phase relation of a DUT Device Under Test connected between the input and output port It also presents a time domain or distance response curve time domain window can be used to single out the response of a specific element in the network This feature will be very useful for fault finding The RFT has two identical input output channels which makes it possible to use one path to perform the measurement while the other channel is used as a reference Since the two channels are identical this will increase system stability and accuracy Reflection measurements can be performed using an external directional coupler to perform SWR and S parameter measurements The equipment has an internal modular setup in order to obtain maximum flexibility and future extension provisions The unit is operated from a personal computer using virtual front panels This allows easy access to functions like data storage hard copy and transfer of data to spreadsheet like software The RFT646 is connected to the PC via the USB interface The cable set delivered with the Radar Rf Testset is not indented to be of the highest quality for Rf signal connection since high quality Rf cables are not
29. INTERSOFT cEwreneTHE aH aS Radar Rf Testset RF T646 User Manual Edition 1 Date 25 Nov 09 Status Draft Issue WWW INTERSOFT ELECTRONICS COM Radar Rf Testset RFT646 Edition Date 25 Nov 09 DocuUMENT CHARACTERISTICS Radar Rf Testset RF T646 User Manual Edition 1 Edition Date 25 November 2009 Status Draft Issue Keywords User manual RFT646 Rf Testset Abstract Author This user manual describes the use of the RFT646 Contact Information Elke Vanuytven Editor Elke Vanuytven Contact Person Niels Van Hoef Tel 32 14 23 18 11 E mail Address Document Name support intersoft electronics com Document Control Information IE UM 00166 001 RFT646 User Manual odt Path C Documents and Settings elke Desktop RASS S User Manuals RFT646 Host System Mac OS X 10 5 6 Software OpenOffice org 3 0 1 Size i IE UM 00166 001 RF 1646 User Manual odt 2151 821021Bytes Radar Rf Testset RFT646 Edition Date 25 Nov 09 Document CHANGE RECORD Pages Approved Affected by 001 09 07 29 New Document All EV Revision Date Reasons for change IE UM 00166 001 RF 1646 User Manual odt 3 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 TABLE OF CONTENTS 1 TECHNICAL MANUAL RF 1040 uu ui GN RY YU G YRR O GL REWN ND GA RR DRA G R NEUR A ARR EU AA W
30. ONE uc aueiiaciei aiii a YGU BA YNYR D OND nunnu ennen DUON na 13 Figure4 ReflecHon measuremeni is iiiieuis ai iiA Mind Fo FWBUA ENDS AUU bad RO NNRUORW DA AGA N N GROS O 13 Figure 5 Overview of mathematical computatiOnS nnarrvnxnnnnnnnnnnunennnnnnnnnnennnnnnnnnnnnnnnnnnnnnennnnnnnnnnnnnnnnnnnnnnr 14 Figure 6 RFT646 connections for VNA transmission measurement asrrrnanunrrnnnanennnvanennnnnnennnennennnnnnur 15 Figure 1 VINA SONWANE EEE EEE EEE 15 Figure 8 Sweep NINE 15 Figure 9 Result of reference measurement stability Of measurement narrnnunnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnr 16 FIQUIC TO NOISE OVE ssis e EE UO NON CS SUR ARG RO AEAEE NEE EE OEE EEE 17 Figure 11 VNA transmission measurement reSult rr nxrrnurnnnunnnunnnnnnennnnnannennnnnnnnennennnnnennnnennnnnnnnnnnnnnnnnnner 17 Figu ur 12 VNAmeasuremen FO SO esses decsiemerensusecsveteesoewntncunnatoneasnienanteseeicieanaaneneusiawesndonanesenmentnasereeeassninanes 19 Figure 13 RFT646 connections for VNA reflection measuremenft nrrrnnnrnnnnnnnnnnnnnnnanennnnnnnnnnnnnnnnnnnnnnnnnr 21 FIOUeTT VNA STINE eare ETE EE A E E RO YN EY EEES 21 Figure 15 VNA Reflection measurement Example Set up arr nnrananunnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnr 22 Figure 16 Example measurement TOSI E iviecsdeneeiccnconsvcaninniesswnevivoumnetniwessnenentbasccneenwatevexstinesotesdessivanessevenauas 22 ad 1 Jr ado 0 1 EEE EEE CN YY A YY FF CY 23 Figure 18 Ti
31. S equipment can be determined by software 1 2 Key Features Following functionalities are available for the RFT646 e General Vector Network Analysis VNA measurement of VSWR reflective power forward and reverse transmission e Dedicated VNA with far field prediction software for M SSR LVA antenna e Dedicated VNA with scanning software for 3D PSR antenna e Pulse Vector Volt meter 1 3 Hardware Description 1 3 1 Block Diagram The block diagram below shows the most important building blocks of the RFT646 The RF front end consists of two linear receivers for baseband signal processing as is required to perform VNA measurements Additionally each receiver module has a log receiver channel whose output is always available at the RFT back panel A number of switches are put in between to make the ADC input selectable Lin Rx Log Rx or the External video input Sampling can be triggered in various ways depending on the DSP program loaded and signals available e Analog a DAC and a comparator allow to trigger at a selectable level For this purpose the Reference receiver output can be connected tot the trigger circuitry e Digital triggering on the external TTL level trigger signal input e Internal triggering under software timer control A Tx output is available to generate a stimulus signal It can be a swept or a fixed frequency in the range 900 MHz to 3500 MHz A 63dB digital step attenuator with a 0 5dB step size provides the
32. SMA Column Fault Finding kit O 1 Dipole antenna probe mountable O 1 Probe mounting stick IE UM 00166 001 RF 1646 User Manual odt 50 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 6 5 Annex 5 Configuration List 3D Scan Check Qty Description Item List 3D Scan Antenna Kit O 1 Dipole Antenna Probe O 1 Antenna Scan Board L Band O 1 Antenna Scan Board S band 3D Scan Accessories Cramp BNC m to BNC m RG223 5m black Velcro Strip hook reel 3m 50 mm Velcro Strip loop reel 3m 50mm Accessories box CAT 10 Attenuator 10dB BNC 500 CAT 20 Attenuator 20dB BNC 500 BNC f straight adaptor RJ45 RJ45 8 way coupler CAT5 STP patch cord RJ45 RJ45 5m DB9 m to RJ45 FTP CAT5 cable 2 5m DB9 f to RJ45 FTP CAT5 cable 2 5m O O O O 000 O O O 2 BR RAOUN DY B BAND ON O Encoder stick P577 Encoder stick Tape measure Lufkin 20m Aluminium bar plastic screen 10m x 50cm O 000060 KR 0 a Bolt wing nut IE UM 00166 001 RFT646 User Manual odt 51 51
33. a button allows you to save a table to disk after you have filled it in to build the custom radiation pattern IE UM 00166 001 RF 1646 User Manual odt 26 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 Other important input parameters for the mathematical calculations need to be entered in the Parameters section Table 2 Parameters for antenna simulation Element separation Distance between dipoles Step Simulation resolution in degrees Frequency Frequency used for simulation Noise Phase noise Phase or amplitude noise can be added mathematically to analyse the influence of manufacturing deviations Antenna bending Some M SSR antennas are bended in the center to create a split backlobe Offset Offset in displayed antenna pattern Rel Abs Relative values of the amplitude related to zero or absolute values can be shown in the graph Changing any of these parameters will cause a recalculation of the curve The same can be achieved using the L amp JRecalc button Both the antenna pattern and the 3dB beamwidth are calculated based on the above mentioned parameters and dipole pattern and displayed as in figure 21 The View selector in the top right corner of the software vi allows you to switch between 1 Antenna Pattern displays the simulated antenna pattern rel gain vs azimuth 2 Phase shows the calculated phase vs azimuth 3 Tapering shows the measured attenuation and phase o
34. able max side lobe level or to reduce the notches in the main beam for example IE succesfully installed 40 phase adjusters in a Martello S723 and used the software to remove the sidelobes towards the ground 1 Open the Tune Tx Pattern program from the lrune Tapering button in the View PSR Far Field program i gt Tune Tx Pattern2 vi File Edit Operate Tools Browse Window Help BEE EES O r Max Delta Phase r Phase Adjustment 120 00 Length mm 255 r Tuning Speed 5 0 240 10 0 p a 0 0 Y 00 r Extra tilt deg 0 00 r Sliders al Limit LJ gae r Method EG Sidelobe p yg ey Readout 7 00 196 00 TE TRT r ntenna Diagram New p PN original 74 1 1 I 1 1 I 1 1 40 0 30 0 20 10 0 0 10 0 20 0 30 0 40 0 18 KAR r pan gd BE pi EDO EA Figure 42 Tune Tx Pattern software 2 The user needs to set the cursors in the negative elevation region of the vertical diagram as the part of the antenna diagram between the cursors will be improved by software simulation in order reduce the sidelobe levels Initially the position of the phase adjusters is set by default to 196mm being exactly in the middle of their range 3 Incase you have other settings you can load the slider position file either using the import slider positions button or use the Load Slider Positions file button This loads the slider IE UM 00166
35. am is already presented in the View PSR Far Field program To allow to correct for the measurement probe s surfboard calibration at least once a calibration scan of the surfboard must be performed This is done by switching off all transmitters except one in the middle This allows to measure the selectivity of the surfboard amp View PSR Far Field vi File Edit Operate Tools Window Help BCACACOA r Antenna Tapering 1 Antenna Pattern as ae 1 1 l I I I I I 20 0 10 0 0 0 10 0 20 0 30 0 40 0 50 0 fe Eurso F40 00 Jdeghian hem Antenna Parameters Simulation Parameters Frequency 1295 00 MHz Step 5ize p 20 deg Element separation 0 01750 m Amplitude noise 0 00 dB Mechanical Tilt 10 0 deg Phase noise 0 00 deg TxPattern gt Offset 90 00 dB Figure 36 View PSR Far Field software kezi Open the View PSR Far Field program from the lese VNA button in the RASS S6 Toolbox 1 Click the toad Scan File button to select a VNA scan file from disk A dialog box will pop up pointing to the NETWORK VNA FILE subdirectory of the active campaign folder Select the file of interest and click OK 2 The View VNA Scan vi will pop up It shows the scan data Both amplitude and phase are shown versus encoder position or row position Two cursors are available to select the data part of interest Make sure to point the cursors to the correct position During this pr
36. correction table The phase corrections required for the improvement can be applied using sliding line phase adjusters selected by Intersoft Electronics The initial developments of the above mentioned tools were started in the context of a study with the goal to reduce the interference towards the close environment 5 2 3D Scan Hardware Set up When setting up to perform the Near Field Scan Transmission Measurement please follow the listed instructions and check Annex 2 3D Scan Transmission Connection Diagram 1 Power up the Radar RF Testset and let it warm up For transmission measurements it is best to pick a location in the spine 2 Carry all the encoder stick parts up the spine 3 pairs of bolts and wingnuts the encoder stick 2 aluminium bars 1 DB9 f to RJ45 cable 2 RJ45 cables 5 m 2 RJ45 8 way sockets the tape measure 20m and 2 cramps 3 Assemble the encoder stick as shown in figure 31 and put the tape measure across the encoder wheel ay Figure 31 Assembly of 3DS encoder stick IE UM 00166 001 RF 1646 User Manual odt 33 91 Radar Rf Testset RFT646 Edition Date 25 Nov 09 4 Pull out 10m of the tape and throw it down in front of the antenna 5 Fix the encoder stick to the spine s roof using the cramps Try to take a location in the horizontal middle of the antenna Make sure that the tape is free when you fasten the cramps Try to put the encoder wheel in the plane of the antenna surface see fig
37. d ones marked with an asterix by clicking the d Export button The Print Tables program will open and display the data for export Click the a Return button to return to the Tune Tx Pattern program and click the Ol pone button to return to the View PSR Far Field program The original antenna diagram is put in reference while the improved antenna diagram is copied to the Tx Channel Please note that the tapering table is entered in the Antenna Tapering table This way both antenna diagram and tapering table are available for saving to file Finally it is time to adjust the sliders An iterative process of measurement and simulation will lead to successful adjustment to reduce the sidelobes as predicted IE UM 00166 001 RF 1646 User Manual odt 45 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 View PSR Far Field vi E4 Antenna Tapering Graph eae SEA OE 1 000 0 566 10191 2 000 1 084 4 615 ae 4 000 1 611 22 973 5 000 2 712 23 857 9 6 000 4 601 8 161 7 000 4 635 26 139 158 7 9 000 10 739 62 179 20 0 10 000 1 915 _ 69 549 25 0 12 000 1 813 _ 67 838 13 000 Jo s43 64 362 apg 14 000 0 636 56 263 15 000 1 317 52 374 16 000 1 028 57 397 GR 18 000 0 619 71 268 ME Y HN PREN iste 20 000 3 837 83 918 lf eni re ed O Abs 23 000 20 731 14 352 Antenna Parameters Simulation Parameters 24 000 12 419 24 39
38. ding measurement results using the VNA and the antenna patterns measured with the RFA641 equipment 4 Purse Vector VOLTMETER 4 1 Getting Started The Pulse Vector Voltmeter is intended to measure accurately the difference in amplitude and phase between two pulsed Rf signals In the PVV set up the Tx output is used as signal source for the measurement while the external Tx input is used as the reference channel The device under test can be placed in between the 10dB attenuator present at the Rx input and port 2 of the splitter RFT Front 10dB attenuators Splitter ZFRSC 42 Figure 23 PVV Set up Instead of the Tx output any other pulse RF signal source can of course be used and connected the splitter input Make sure to add sufficient attenuation in between The external trigger input is located at the back of the RFT646 In case you want to use it you will need the external trigger cable DB9 to 1 BNC and connect it to the Digital Output connector Ez The program can be loaded by selecting Pulse Vector Voltmeter from the vector Network Analysis button in the RASS S toolbox IE UM 00166 001 RF 1646 User Manual odt 28 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 4 2 pi Pulse Vector Voltmeter2 vi Seles File Edit Operate Tools Window Help FN BEN 3 0 m Signal display Trigger Amplitude amp Phase Mode Meter p External Diff Ch1 Ch2 Analog M Level
39. e IStart button and start pulling the antenna scan board slowly upwards 9 The vertical scan data will be updated as you continue with the scan Vertical Scan Data Amplitude 20 0 a Tidl hall au V TE THAU En i TO 600 800 1000 1200 1400 1600 1800 2000 2200 2400 Phase 150 0 gt 50 0 A 2nn 300 500 200 1000 1200 1400 1600 1800 2000 2200 Hela ir ale Figure 35 Vertical scan data while performing a near field scan 10 Scan the antenna until you reach the top row number 40 5 and move the scan board back to perform a downward measurement When the antenna scan board has reached row position 0 5 IE UM 00166 001 RF 1646 User Manual odt 31 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 push the stop button to stop the measurement 11 Save the antenna scan data to a file on the computer hard disk by using the save button The Save File dialog will point by default to the NETWORK VNA_FILE subdirectory of the active campaign folder 5 3 4 Calculating the PSR Far Field Diagram 5 3 4 1 View PSR Far Field Once the antenna tapering is measured the scan file can be loaded into the View PSR Far Field program This allows to predict the far field from the measured near field The View VNA Scan File function allows to view the measured amplitude and phase versus row number and calculates the tapering At the same time the resulting antenna diagr
40. e the RFT646 will trigger on a reference signal connected to the External Tx input The trigger level can be set o Timer In this mode the RFT646 will generate a CW signal at the Tx Output Power level can be set with the CW Power control the internal reference will be used In this mode the sample windows are started each 4ms Start measuring by clicking the start button The signals present on the two RF channels are both displayed in real time while they are measured The values of the samples are shown on the display as they are presented to the Analog to Digital Convertors ADC All 512 samples per channel are shown on the display but only the samples between the two cursors are used to calculate the difference in phase and amplitude Rx Ref IE UM 00166 001 RF 1646 User Manual odt 29 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 i gt Pulse Vector Voltmeter2 vi Signal display Trigger r Amplitude amp Phase 20 Mode Meter v v EK En Diff Ch1 Ch2 Analog Timer Level dBm 10 3 f 25 0 50 0 ly Ls BF 7 36 il i 280 azl pi aay I fione zl widow I enw 24A 1000 22 50 0 199 9 r Settings CW Power Calibrate Holdoff us Signal frequency 200 00 MH TD TEN cB En a solute 0 00 0 Averaging Phase deg a ji Sampl 82 0 dB R Jest 3 Figure 25 PVV Software Example 4 Once the measurement is
41. ecsanseanecsanseaneceanseansenensecnenaesnensennanaes 46 Figure 47 Column Fault Finding connection diagram rrr nanrnnunnnnnnnnnnnnnnnnnnennnnnnnnnnnnnnnnnnnnnnnnnnnrnnnnennnnnnnnr 47 Figure 48 3D Scan Transmission connection diagram nrrranxnrnnunennnnnnnnnnnnnnnnnnnnnennnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnr 48 Figure 49 3D Scan Reception connection diagram a rrnnnxrnnnnnnnunnnnnnnnnnnnnnnnnnennnnennnnnnnnnnnnnnnrnnnnnnnnnnnnnnnnnnnr 49 IE UM 00166 001 RFT646 User Manual odt Radar Rf Testset RFT646 Edition Date 25 Nov 09 TABLE OF TABLES Table 1 Reflection and transmission parameterS rr nnrrnnnnnannnnnnnnnnnnnnnnnnnnnnnnnnnnnnrnnnnnnnnnnnnnnnnnnnnnnnnnnnunnunnuen 13 Table 2 Parameters for antenna SIMULATION 1ccccceccccecececccecccnencecncenensncnnsennsnsnsncenenenensncncnnennsnnsnnsansnnsanses 27 IE UM 00166 001 RF 1646 User Manual odt a Radar Rf Testset RFT646 Edition Date 25 Nov 09 Conventions USED a Note This icon to the left of bold italicized text denotes a note which alerts you to important information i Caution This icon to the left of bold italicized text denotes a caution which alerts you to the possibility of data loss or a system crash 6 Warning This icon to the left of bold italicized text denotes a warning which alerts you to t he possibility of damage to you or your eguipment IE UM 00166 001 RFT646 User Manual odt 8 51 Radar
42. equency 11000 000 Stop frequency 11128 000 Step frequency a vil oo i i i Cursor Readout 1000 0 1020 0 1040 0 1060 0 1100 0 1120 0 ursor Readou ME a S DI uro ione OG EG Amplitude EAGER Eur Jesso olfs72 E Jl 0 0 r Time domain curve Filter On _ 8 0E 0 6 0E 0 4 0E 0 2 0E 0 0 0E 0 I 0 0E 0 20 0E 6 40 0E 6 60 0 me I 1 1 1 1 1 1 1000 0 1020 0 1040 0 1060 0 1080 0 1100 0 1120 0 1140 0 IEA 4 DA pp je Guri p 0E 0 E 5 Time velocity factor ill Jr ren at If ve dl Cur2 60 0E 6 EE Distance 9 06 Figure 9 Result of reference measurement stability of measurement 3 By disconnecting the input of the RFT646 you can verify the noise level It should be below 55dB IE UM 00166 001 RF 1646 User Manual odt 16 51 Radar Rf Testset RFT646 gt Vec torNetworkAnalyser vi Sweeping Edition Date 25 Nov 09 7 OS 1000 0 IE a EET N ONY wh hs wm lt 1020 0 1040 0 Attenuation x I 1060 0 y x Y 1120 0 Jes IE Eur eso elle 1 I 1080 0 1100 0 1 1140 0 MHz 100 150 200 1000 0 NE B UDE vg n I 1020 0 1040 0 I 1060 0 1 I I 1080 0 1100 0 1120 0 BE Log file Info Sweep Parameters Start Frequency 1000 000 Stop frequency 11128 000 Step Frequency ai y To Fa F
43. f Testset RFT646 Edition Date 25 Nov 09 Radar Rf Testset RFT646 IE 10dB attenuator and 2m BNC cable Figure 6 RFT646 connections for VNA transmission measurement When the connections are made load the Vector Network Analysis tool from the ENA button in the RASS S toolbox gt VectorNetworkAnalyser vi File Edit Operate Tools Window Help 2 go Click LabVIEW Run button to start m Amplitude Attenuation J d 0 0 x 10 0 r Progress To Spreadsheet SSS 30 0 rSweep Parameters 40 0 Start frequency 11000 000 Stop frequency 60 0 1128 000 70 0 Step frequency 32 000 50 0 80 0 1 1 1 1 1 1 1 1 1 1 0 0 250 0 500 0 750 0 1000 0 1250 0 1500 0 1750 0 2000 0 2250 0 2500 0 2750 0 3000 0 IE S Euro foscos OE MHz cursor Readout aaa SO mer rea snp r Phase 0 0 200 Phase 150 0 0 100 r Time domain curve 50 Filter On _ 0 300 0E 3 50 200 0E 3 100 100 0E 3 150 cur 1 0 0E 0 0 0E 0 1 1 40 0E 3 60 0E 3 200 1 1 1 1 U 1 U 1 1 U 2500 0 2550 0 2600 0 2650 0 2700 0 2750 0 2800 0 2850 0 2900 0 2950 0 3000 0 20 0E 3 Ee Ed MHz JJ anan gg Curd co JOE Time velocity Factor MARTA OLY vy gy re B e M Distance 306 N Br Figure 7 VNA Software 2 2 2 Performing a VNA Transmission Measurement 1 Run the software tool and select t
44. f each dipole in the graph When selecting the Tapering displaying method one can easily spot the broken columns since these will pop out of the normal tapering distribution The example below is a purely graphical representation of the numerical data entered in the tapering table e the red curve shows the attenuation versus element number in this example it can be clearly seen that f e element number 11 is faulty e the green curve shows the measured phase versus element number one can see that indeed 11 has a phase popping out of the normal readings dB degrees att 90 0 frr i 1 t t hi Kii 7il Ti 7i Phasi I I I I I I I I I I I I I I I 4 6 8 10 lz PR 16 185 2 22 24 26 28 amp 30 X32 X34 x36 0 2 lJ ARR amp a Element oe Erebus gt Figure 22 Antenna simulation example after loading a tapering file Now switch back to the Antenna Pattern view The Pi save HPD Data button allows you to create a data IE UM 00166 001 RF 1646 User Manual odt 27 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 file with the same file format as the PSR and or SSR HPD files The Export VNA data window will pop up a type selector allows you to select the resulting diagram type of the export The resulting file will be placed in the corresponding subdirectory of the active campaign folder The data can be reviewed using the Vew HPD Logfiles tool This feature can be useful in comparing the column faultfin
45. he RASS S toolbox IE UM 00166 001 RFT646 User Manual odt 34 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 i gt Near Field Scan RFT 646 vi File Edit Operate Tools Window Help T eee Signal display r Amplitude amp Phase Settings Frequenc b3 20dB z l 1295 00 MHz Averaging 2 Ital 10 0 99 10 0 Tx Power 20 0 20 0 0 00 _ dBm m Reference 100 0 00 100 0 Internal z 180 0 gt A 180 0 gt d My r Calibrate Amp dB us SER 1 1 1 I 1 I a 0 0 5 0 10 0 15 0 20 0 25 0 30 0 35 0 A bsolutel 2 60 Me CS vp T oo deg W M Phase deg Ur w Xx None y Window Env R iative r Vertical Scan Data eel Amplitude gt m 10 00 a anc Method 2 Surfboard 10 00 20 00 r Row Number 30 00 1 1 1 I I 1 I 1 I 1 1 1 1 0 25N 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000 NF ps A i Bottom _ I l I I I I I 1 I I I 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000 ME ry l Figure 32 Near Field Scan software 5 3 2 Basic Software Introduction The tool consists of a Pulse Vector Voltmeter function which allows to sample two signals simultaneously and calculate the amplitude and phase difference The signal used as a reference can be either an external signal from the
46. he frequency range of interest and the step size These settings will affect the measurement time Sweep Parameters Start Frequency 4 1000 000 Stop Frequency 1128 000 Step Frequency 2 000 Figure 8 Sweep parameters 2 The first time the tool is started it will automatically perform a reference measurement it is therefore important that the device under test is removed and that the Tx and Rx are connected together with a barrel as shown in figure 6 Now start the tool by clicking the start button You will notice that the Take Reference button is automatically dimmed as well When required you can always perform a reference measurement in between measurements by clicking the Take Reference IE UM 00166 001 RFT646 User Manual odt 15 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 button Since the software assumes there is no DUT present the result of this reference measurement will be accepted by the software as the compensation to be subtracted from the next measurement sweeps assuming the reference connection corresponds to OdB attenuation and Odeg phase deviation Once the reference measurement is performed you will see the result of the consecutive sweeps While the reference connections are still in place you will see the stability of the measurement both in amplitude and phase 2 FELT Sweeping Attenuation r Log file Sweep Parameters To Spreadsheet Start fr
47. he measurement settings must be entered o Select the correct frequency In case the radar performs a chirp during the pulse transmission it might be necessary to lower the frequency slightly Select the frequency setting that gives max amplitude at the start of the pulse Normally the Signal display shows a 2 3 MHz signal When the frequency is OK an indicator will turn from red into green o Averaging This is the number of sample windows that will be averaged to produce an amplitude and phase sample By default it is set to 2 It is not likely that it needs to be increased o Tx Attenuation This controls the attenuators that are built in in the Tx outputs of the RF Testset By default the attenuation is set to OdB o Trigger Mode Select the analog trigger mode to measure the transmit diagram o Trigger Level The sensitivity of the analog trigger circuitry can be set according to the signal level available at the reference channel o Delay Use this control to adjust the delay after trigger to change the sample position in the pulse 3 In case the signal level is too low or too high you can adjust the Rf input attenuation by changing the external attenuators until the Signal display shows the signals within range The signal strength is preferably between 1 and 2 Volt pt NN m HL MUM lf 8 AIF 5 ee aw x hone Env Figure 33 Signal Display i Hi uu 10 0 4 Take reference push the Relative button f
48. ient Group delay S11 S22 S21 S12 The transmission parameters and reflection parameters are measured separately Both measurements start with a take reference procedure The reference from which the relative measurement is performed is based upon a physical law 2 1 2 1 Transmission Parameters Stimulus Ff 1 DUT transmitted gt signal to be measured Reflected stimulus reference signal Figure 3 Transmission measurement In this measurement it is assumed that the DUT is matched in impedance The error in matching will reduce the accuracy a little For instance a VSWR of 1 5 or a return signal of 14dB on the transmission evokes a measurement uncertainty of 1 6dB A VSWR of 3 6dB return evokes a measurement uncertainty of 3 5dB 2 1 2 2 Reflection Parameters Stimulus DUT 2 Transmitted Reflected signal to be measured stimulus reference signal Figure 4 Reflection measurement In the setup of the transmission measurement the effect of a small mismatch was negligible This measurement will focus on the reflection aspect First the reference will be taken with all the energy reflected open circuit When the DUT is connected due to the effect of absorption the difference with the reference is to be measured From this measurement all the reflection parameters can be calculated IE UM 00166 001 RFT646 User Manual odt 13 51 Radar Rf Testset RFT646 Edition Date 25 Nov
49. le Time domain curve Filter On 4 0 0E 0 10 0E 0 20 0E 0 30 0E il LB i i Alt Cur 1 poro QB Time velocity Factor Uran cor z B2 45 0 Old BG Distance 40 66 Figure 17 Time domain curve As a first reflection the BNC straight connector jack jumps out at a distance of 8m Please reconsider that this connector jack was actually after a 4m cable The next reflection 4m further is the second BNC jack but also the cable type changes resulting in a bigger impedance mismatch and therefore a greater reflection Another reflection you can see is the BNC MCX connection resulting in the biggest reflection of all three Notice that the velocity factor of the coax had to be inserted The physical and the electrical length seem to correspond very well 2 3 3 2 Calculate the VSWR of a Specific Part of the Transmission Chain In the transmission chain of the example there were several parts which reflected It may seem the best solution trying to fix the worst part of the transmission chain if it is possible to fix of course In the time domain you move the cursors to isolate the occurrence you want to focus on Do not place the cursors to narrow Keep in mind that because of the bandwidth limitation spreading occurs Time domain curve Filter On y 80 0E 3 60 0E 3 40 0E 3 20 0E 3 I 0 0E 0 ms i 0 0E 0 10 0E 0 20 0E 0 30 0E IPE AF Cur 1 fiz ce o m E Time velocity Factor vga Curo 5 0640 JIT JE H Distance 6
50. me domain curve selection with CUISOIS rxrrraxrranunnnunnnnnnnnunnnnnnnnnnnnnnnennennnnnennnnnernnnnennnnner 23 Figure 19 Attenuation of selected reflection arr nxrrvanunnnnnnennnanennnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnennnennnnnnnnnnnnnnnnnr 24 Figure 20 Radar Antenna Simulation Software arrranarrnnunnnnnnnnnnunennnnnnnnnnennnnnnnnnnnnnnnnnnnnnernnnnrnnenennnnnnnnnnnnnr 25 Figure 21 Antenna simulation example after loading a tapering file rrnrrrrnnurennnnrnnnannnnnnnnnnnnnnnnnnnnnnnnnr 26 Figure 22 Antenna simulation example after loading a tapering file rrnrrrrnnunrnnnnnnnnannnnnnnnnnnnnnnnnnnnnnnnnr 27 FONE FV SN en 28 Figure 24 PVV SONWANE hook RF 29 PIQUIE 25 PVV SOM Wale BANNE soseri ereraa Ea EAR ANO EE EE MAU 30 Figure 26 Envelope TUNC UON sssrini nE EE DEEA EARE EOE EEEE EE AAEE E EEEE 30 Figure 21 Window NC UON S seere edda AN RAD FEN OUYN OM 30 Figure 28 Example of Hamming window rrevnnnnvnnnnnnnnnrnnnnnennnunennnnnnnnnnnnnnnnnnnnrnnnnnennnnnnnnnnennnennnnnnnnnnnnnnnnnr 31 Figure 29 Example OF callbraHOlluii aii Wini ddia YNGL OES FA FN YG ANO YU 31 Figure 30 Displaying options Meter left or Scope right nrrrnnanennnnnnnnnnnnnnnnnnnnnnnnnnernnnnnnnnnnnnennnnnnnnnnr 32 Figure 37 Assembly of 3DS encoder SUCK vscicsisserisuncossxesabsvearevsseriiedessientanenssansdediebsaayasesnecbsbecasuuuncepebsbinbiens 33 Figure 32 Near Field Scan SOMW al G G N GU GWER DOWN ENA CNC GEG MAFON NR GLOD
51. ment sweep was already taking place The next sweep provides the correct result IE UM 00166 001 RFT646 User Manual odt 21 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 2 3 3 How to read the results 2 3 3 1 Measurement Example In this example you can see the reflections from connectors cabling and environmental reflections To demonstrate this function a calculation of the SWR of a straight BNC jack will be performed The user can practice on a similar setup with the equipment available in the RASS S configuration It is recommended to use the longest cables as the result will be more obvious This example contains one 4m BNC BNC cable RFA641 kit one 2m BNC BNC cable 2 straight BNC jacks and a BNC MCX antenna cable RFA641 kit Figure 15 VNA Reflection measurement Example Set up There are two important things about reflections to keep in mind in this measurement 1 The distance that is displayed is twice as much since the signal travels back 2 A passive element will meet the reflected signal twice resulting in double loss figures amp VectorNetworkAnalyser vi ifm Stopped O r Amplitude Log file Info r Progress To Spreadsheet BE nr fatt dB Phase A Start frequency EJ aj 3200000 ed Stop freguency TE is a 1300 000 Ss Step frequency EJ a 31 000 Sa 60 0 i 1 I i I 1 I 1 ETE 800 0 850 0 900 0 950 0 1000 0 1050 0 1100 0 1150 0 1
52. n use measured or simulated data as an input for the mathematical computations Ese The program can be loaded by selecting Radar Antenna Simulation from the vector Network Analysis button in the RASS S toolbox E SSRsym vi File Edit Operate Tools Window Help EE r Tapering r Antenna 0 0 10 0 F 15 0 H 20 0 25 0 H 30 0 4 35 0 40 0 45 0 50 0 55 0 60 0 65 0 70 0 SD 80 0 85 0 90 0 I I I 1 I 1 I 1 1 1 1 1 1 Li 180 0 150 0 125 0 100 0 75 0 50 0 250 00 25 0 500 75 0 100 0 125 0 150 0 180 0 ll eS Faro 100 00 deafinr elm g r Parameters degree dBs Element separation 0 22500 m EE re Step 0 10 mirror Qabs Frequency 1090 00 MHz r Single Dipole noise 0 00 dB Phase noise sooo e Doo Antenna bending 0 00 e Beamwidth Han offset 0 00 ds Figure 20 Radar Antenna Simulation Software 3 2 Calculating the Far Field Pattern Load the measured tapering file using the E oaa Tapering button in the Tapering section A standard file dialog window will appear asking to select the tapering file The file dialog by default points to the Tapering subdirectory of the Network directory of the active campaign folder IE UM 00166 001 RFT646 User Manual odt 25 51 i Radar Rf Testset RFT646 Edition Date 25 Nov 09 Dipole fas t
53. ocess the far field pattern is shown in the far field program The horizontal axis represents the encoder position The file data is combined to 400 samples equally distributed across the antenna surface In case the encoder is calibrated the X axis will be converted to row number The measurement should contain two scans up and down In the window of the original VNA data the user can see the repeatability of the measurement for phase and IE UM 00166 001 RF 1646 User Manual odt 38 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 amplitude by zooming in on a specific part Original VNA Data Reference Tapering File gt 10deg VNA ADO r Amplitude I 1 1 I 25 0 30 0 35 0 40 0 VF elena Euro o0 deg 3 05 Helm IDE 9 s mE ae i Ae Ped ee garn s gt a i ei el L 1 I 4 L we 45 0 I i y e Unwrap I 12 8 12 9 13 0 13 1 132 Figure 37 View VNA Scan software result checking the repeatability in the original data right 3 The next step is to load the reference file The Reference Scan is a surfboard measurement across the whole antenna array with only one transmitter radiating This file will be used to process the data with the mathematic operation of deconvolution To load the reference file click on the Reference tab and click the EP oad File button to select the reference IE UM 00166
54. re NIU OCU GOP sene 35 5 3 3 Using the Near Field Scan Measurement Software rrrrrrrnrnrnrrnnnrnnnnnnnnnrenrnnnnrnnrrvnnennerrnennnnner 36 5 3 4 Calculating the PSR Far Field Diagram rrrnnnrnnnnnnnnnnnnnnnnnrnnrnvnnnnrnnnnrnnnnennnnnennnnnnnnanennnnnernnennennn 38 5 3 4 1 View PSR Far 0 EEE NN 38 5 0 4 2 TUNG Ne Verical DIGI AN essien GAU NN RCH ARA A AEEA Siw E ER GO 43 O ANNEXES EE EEE E EEE 47 6 1 Annex 1 CFF Connection Diagram r rnnxuvnnnuvnnnnnnnnnnnnnnnnnnnnnnnnnnennnnnnnnnnernnnnnennnnnnnnnrnnnnennnnnnnnunnnnnner 47 6 2 Annex 2 3D Scan Transmission Connection Diagram rrannnxnnnnunnnnnnnnnnnnnnnnnnnnnnvnnnnennnnnnnnnnennnnnnnen 48 6 3 Annex 3 3D Scan Reception Connection Diagram r arurrnnnnnnnnnvnnnnnnnnnnnnnnnennnnnnnnnnnnnnnnnnnnnnnnnnnen 49 6 4 Annex 4 Configuration List RFT646 nrrnnnnrnnnnnrnnnnnnnnnnnnnnnnnnnnnnnnnnvnnnnennnnnnennnernnnnrnnnnennnnennnnnnnnnnen 50 6 5 Annex 5 Configuration List 3D Scan rannurnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnernnnnnnnnnnnnnnnrnnnnennnnnennnnennnnnnnen 51 IE UM 00166 001 RFT646 User Manual odt 5 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 TABLE OF FIGURES Figur 1 I 16460 Block DIAGRAM sxssiesessizetarncucensonestennnatsetinacerstmaretusewansdensiuserecndsceedaeuanssestceasosancuatecsezeldcions 11 Figure 2 Principle or reHlec lloft iii kic dwn NN DA WAUN SN YDA WG SG DDU DAWDD GN 12 Figure 3 Transmission MCASUICIM
55. re used to calculate the positions of the row amplitude and row phase values These are indicated using the red dots on the graph Purpose of this is to check for rows with problems f e a broken transmitter Once both cursors are set correctly the amplitude and phase tapering becomes visible Ara pb nude r mokude A ate 10 0 HN TEA es en am A a ii gg Lan ee S oa can dy Ec Tapar j Ew NE ME OA Taperg ae cn er aU y k E ae i ae po re EU ah A Gaii an i004 7 as i 160 i LO ra i g i 1 i I 1 1 I E MH 1 I i 1 1 I 1 I nel L D 2 00 FIL A 00 i Pa 70 Ble 29 95 MDO 4050 41 00 4135 4200 425 HYO 5232 40 Aa Page ojpi deg 2 em Eea Erol deg 2 47 hm H ft l OCH amp Mer Brees f l OEH Figure 39 Placing the cursors on row 2 left and on the second last row right Original YNA Data Reference Tapering Rows ml aml nt r Se mm Pare P x oH Bc ee er Hr Y Hr I I I 3 00 10 00 15 00 z000 25 00 30 00 35 00 40 00 45 00 iP ee fur O39 deg 2 47 KLE EG ME eg uri Bas Lae MLE aces GE nt an Figure 40 Amplitude and phase tapering result IE UM 00166 001 RFT646 User Manual odt 41 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 6 The save button allows to save the tapering all 400 points of the selected tab When you select the Original VNA data tab the uncorrected tapering as wa
56. ring field also provides a mirror option selector in the Tapering section When the mirror option is selected the software will mirror the tapering table except for the last element and add this internally to the loaded table This way only half of the dipole elements need to be entered for simulation but of course the antenna pattern is then generated assuming that the antenna is perfectly symmetrical In case all dipoles are measured the mirror function should be off default setting To be able to perform a mathematical calculation of the antenna pattern the user should load a dipole element antenna pattern Depending on the loaded tapering data the dipole information should contain a horizontal or vertical radiation pattern The RASS S software contains default radiation patterns for the horizontal and vertical direction To load a dipole pattern click the E oad Dipole Data button in the Single Dipole section of the software vi A standard file dialog window will appear asking to select the dipole radiation pattern The radiation patterns that are included by default in the RASS S software can be found on the Network gt gt Dipole subdirectory of the active campaign folder When the radiation patterns is selected the pattern is loaded and shown in the Single Dipole section in the example shown in figure 21 the omni reflector pattern was selected You can also enter a know radiation pattern in spreadsheet input The El save Dipole Dat
57. rom the Calibrate box and verify that the signal is stable 0 1 dB and 3deg phase 9 Make sure that the encoder cable is connected on the RF T646 backpanel s digital input Position the antenna scan board on the top row and em the row number 40 in the dedicated control in the Top section of the software Then push the E Top Row Assignment button IE UM 00166 001 RFT646 User Manual odt 36 51 Radar Rf Testset RFT646 Edition Date 25 Nov 09 6 Bring the antenna scan board down smoothly and position the centre of the antenna scan board on the bottom row Enter the row number 1 in the dedicated control in the Bottom section of the software and push the F IBottom Row Assignment button Note While moving the surfboard make sure to adjust the pulling speed according to the Pulse Rate Indicator at the right bottom of the window In order to make sure the encoder s Signals are sampled correctly the speed should be below 5 The indicator will turn red _ from 7 and above indicating speed is too high 7 Deselect the checkbox in the Amplitude and Phase window This will disable the update for this window and doing so speed up the measurement Amplitude amp Phase 1 dB p sh Figure 34 Amplitude and Phase window deselected 8 Position the antenna scan board on the bottom row When moving the row indicator will now track the position of the antenna scan board Start the scan by pushing th
58. s measured is output When you select the Tapering tab the processed tapering is output to file An extra button Bl export Tapering is available in the Tapering tab This allows to save the 40 Marconi S723 or 44 FPS117 rows as selected using the cursors to a tab separated file 7 The PSR far field diagram is calculated and displayed using the default parameters Important are the Frequency and Element Separation parameters The Frequency shall be set to the Tx Frequency of the radar Default this is 1295MHz The element separation must be set according to the distance between two rows divided by 400 rows In case of the S723 this is 0 0175m The mechanical tilt parameter is added to the X axis to allow to add a mechanical tilt if necessary Original YNA Data Reference Tapering Rows gt sys HN Frater dag d in ES O om mEmmREUZII teen TE es ES pdf l lt 85 eee EET N dg borgen EN VEE Ed ner big I I I I 3 00 10 00 15 00 20 00 25 00 30 00 33 00 40 00 45 00 VEE E Kuro i 99_ deg 2 47 HOME o JE va Em les ma BEE S er Ne da MU i ase a hi 0 0 SN i o u i rd i h i 50 0 4 hate ae Rite fn Hau Ao ane A AU AML Hi h Hn Ay j u j 100 0 ra I z 150 0 an I I I I I I I I I 0 0 5 0 10 0 15 0 20 0 75 0 30 0 35 0 40 0 45 0 eee DE ng an Figure 41 PSR far field diagram 8 The simulation parameters can be altered if required The step size can be adjusted to
59. te button Calibrate h Amp dB A bsolu Phase deg R Jeistive The relative calibration procedure measures the difference in phase and amplitude between the two channels at that time with the preferred averaging and uses this result as an offset in future measurements The offsets in phase and amplitude are shown in their respective indicators next to the calibration buttons i Pulse Vector Voltmeter2 vi Signal display Trigger Amplitude amp Phase 2 0 Mode Meter M External Diff Chi Ch2 v he Analog Timer Ue Level dBm I I 10 3 1 25 0 Ed us a 1 I I I I AE 00 5 0 100 15 0 O 30 0 50 0 TT E ets 1iJ I aay y Xx AG soon 00 58909 m Settings CW Power Calibrate Holdoff pus 180 0 Va My X 180 0 Signal frequency An 20 TT 12 0 Max p dB xr d 1200 00 MHz A Josoiste O dl Phase deg Diff Chi Ch2 phase R Jettive oe _20_ sampl 82 0 0 01 de 0 05 Figure 29 Example of calibration By simply switching the connecting cables the absolute calibration procedure enables the de embedding of the measurement paths from the device under test After pushing the Absolute button some dialog boxes appear on the screen posing set up related questions It is important to switch the cables as close to the device under test as possible This way the
60. ure 31 6 Groundassistance Carefully connect the antenna scan board to the tape measure 7 Groundassistance Verify whether the tape can move easily 8 Connect the encoder cable DB9 f to the encoder output cable s DB9 m connector Assemble the cable from the encoder on your way down Add as much sockets for the RJ45 cable as you need At the end connect the cable with the DB9 male connector Plug this cable in the RFT646 digital input 9 Position the reference dipole to one of the lower rows Try to take a different position as where the scan will be performed 10 Extend the cable of the reference dipole and connect it to the RFT646 External Tx input using at least 40dB of attenuation 11 Extend the cable from the antenna scan board with 5m BNC Connect the cable to the Rf input Rx of the RFT646 using 60dB of attenuation 12 Now connect the computer with the USB cable The set up for a Near Field Scan Receiver Measurement is similar and shown in Annex 3 3D Scan Reception Connection Diagram 5 3 Near Field Scan Measurement Software 5 3 1 Getting Started The PVV Near Field Scan tool allows to perform near field measurements Basically this consist of a pulse vector voltmeter measurement performed for a number of positions At the end of the measurement the recorder amplitude and phase together with the positions are saved to the VNA Scan File Now select the RFT646 Near Field Scan software from the Lt IVNA PSR button in t
61. w number by identifying top and bottom rows This is done for ease of use during the measurement and to allow to select samples taking into account the row number later in the analysis phase A near field scan measurement consists of taking as much samples amplitude phase position as possible while slowly moving the surfboard antenna from below the bottom row row1 up to a bit above the top row row 40 then waiting a few seconds and repeat continue the scan in the downward direction IE UM 00166 001 RF 1646 User Manual odt 39 91 Radar Rf Testset RFT646 Edition Date 25 Nov 09 During this procedure the Vertical Scan Data graph will display the measured samples of amplitude and phase for the different positions of the surfboard This data is saved to a file on disk when the scan is stopped This file type is the so called VNA Scan File In the analysis phase the upward scan will be used to calculate the far field vertical pattern NOTE Please note that a reference file is required to be able to analyse the tapering This is a a near field measurement with all transmitters switched off except one This measurement has to be performed once Afterwards the VPD is measured using the transmitters on in the normal operation mode 5 3 3 Using the Near Field Scan Measurement Software 1 Select the Rf as input In the case of transmission measurements the surfboard has to be selected as Method control 2 First of all t
62. x gt VectorNetworkAnalyser vi U U 1 U 1 I 1750 0 2000 0 2250 0 2500 0 2750 0 3000 0 Ero ionos JOE mz r Cursor Readout Amplitude Eur Jesoolsz2 Jm E A 0 0E 0 20 06 3 60 0E 3 U asje pg ag Curt koe OG JG time velocity Factor OE ry am Cur 2 p5 23 JO MG Distance 30 66 iow Figure 14 VNA Software 2 3 2 Performing a VNA Reflection Measurement 1 Run the software tool and select the frequency range of interest and the step size These settings will affect the measurement time 2 The first time the tool is started it will automatically perform a reference measurement it is therefore important that the device under test is removed such that the open end of the coupler s input will reflect MA NUN 100 Now start the tool by clicking the Start button You will notice that the Take Reference button is automatically dimmed as well When required you can always perform a reference measurement in between measurements by clicking the Take Reference button Since the open end reflects as much as possible there can not be more energy reflected nor can the reflection of a DUT be faster since the open end is at distance 0 For the software this is the reference both for amplitude and phase 3 Now the DUT or the transmission chain can be inserted as shown above When the DUT is connected it is probable that a measure

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