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1. SPECTRA VIEWER Product Description and User s Manual PRODUCT NAME spectraViewer VERSION v0 3 1 RELEASE DATE 2012 04 13 AUTHOR Bartosz Lew Spectra Viewer version 0 3 1 Bartosz Lew Torun Centre for Astronomy Nicolaus Copernicus University ul Gagarina 11 87 100 Toru Poland Dated April 13 2012 The spectraViewer program is a dedicated application to present on the fly the intermediate frequency IF spectral gain characteristics of the IF amplifiers used for the super heterodyne receivers installed on 32 m radio telescope in Piwnice It is a TCP IP based client for plotting and collecting data sent from a server that interfaces the communication with the HP8591b spectrum analyzer used to analyze the IF signals from the 32 m radio telescope after first down frequency conversion Its capabilities also include support for radio telescope RT connectivity in order to record the current tele scope time and position along with the history of the IF gain characteristics T O is based on the standard FITS files I PURPOSE AND INFRASTRUCTURE The spectraViewer program was written to visualize the spectra of the IF signals coming from the focus cabin of the 32 m radio telescope RT32 after first frequency down conversion The spectra is calculated using the HP8591b spectrum analyzer connected and controlled via HP IB cable to the PC computer called microlab On this computer a network TCP IP s2. cvs d pserver anonymouscosmos astro umk pl home cvs co r v_0_3_1 spectraViewer B Dependencies There is a substantial amount of self developed libraries that the spectraViewer depends on and they also need to be installed and configured for the proper compilation and linking Required dedicated libraries e mscsfn http cosmos astro umk pl blew mscs php available CVS e CPEDS http cosmos astro umk pl blew cpeds php available CVS e rt32common library common to all programs related to 32 m radio telescope devised by the author available CVS e rtscan http cosmos astro umk pl blew scan_simulator php available CVS e ocraToolkit available CVS Other standard required libraries e qt version gt 4 6 e kdecore kdeui version e gsl e nova e fftw3 e cfitsio e qca Other optional packages e hdf5 ver gt 1 8 if not available remember to edit the spectraViewer pro file and set the appropriate compiler flag DNO_HDF5 default C Compilation VIII CHANGE LOG This section will cover list of important updates to the program if such will be needed IX TROUBLESHOOTING A Icannot change the spectrum analyzer settings What can I do This may happen when the spectrum analyzer server called analink on the microlab computer has problems in re setting the hp8591b spectrum analyzer unit A restart of that server might be required Currently this i
3. all spectra information along with optionally the telescope position information To enable these options check Tools gt Record RT position and Tools gt Store all spectra The spectra are recorded when the Show Record spectra button is checked i e when the spectra view window is open The acquisition of the spectra stops when the spectra view window is closed At this time the recorded spectra are still in the memory and can be saved using File gt Save all as fits However when the spectra view window is closed and re opened again all the recorded information is cleared and the spectra acquisition starts anew This is also indicated by the status bar message indicating the total count of the recorded spectra Any change in the spectrum analyzer parameters also results in clearing the stored spectra buffer An example of recorded observation allows for making a dynamical maps of RFI signals based on the data stored in the FITS files as showed in Fig 5 f MHz 0 00 448 88 E 2 897 76 a D re 1346 63 1795 51 D 28 42 56 70 84 98 time s Figure 5 Gain characteristics spectra history recorded over a period of about 140 seconds VII SOURCES A Download The spectraViewer program is available for download via anonymous CVS using oper trao3 cvs d pserver anonymous cosmos astro umk pl home cvs co spectraViewer To checkout the version v0 3 1 use oper trao3
4. ent settings of the spectrum analyzer defined by the four parameters fa fo r and vp button Get status e setting the four spectrum analyzer parameter button Set all e selecting IF channel combo box channel e activating displaying recording the IF spectra button Show Record spectra e over plotting the single readout spectra Tools gt Show single spectra e over plotting the time averaged spectra Tools gt Show integrated spectra e saving the recorded and integrated spectra to FITS file IV EXTENDED OPTIONS When the Tools gt Show extra features option is checked the program will display buttons that allow setting individual spectrum analyzer parameters Note that it takes some time to send and execute the commands on the spectrum analyzer The extended usage options allow for e connecting to the RT 32 server e acquiring and storing the history of the current position information from RT 32 server option Tools gt Record RT posi tion e storing all spectra readouts option Tools gt store all spectra e simple scaling of the spectra plot e saving all the recorded spectra and RT 32 position information to FITS file A Changing channels Whenever the IF channel selection is changed or different spectra analyzer parameters are set the average spectra information is reset and integrated anew Also all the stored spectra and related RT 32 information optio
5. erver called analink written by Eugeniusz Pazderski is installed The server is used by the spectraViewer program to communicate with the spectrum analyzer in terms of few simple commands Additionally spectraViewer uses VXI TCP IP server and client program located at computer called newfs This server is used for selecting the requested IF channel The IF signals fed into the four IF channels A B C D are defined by the current setting of the distribution and their configuration is discussed in a separate document t4 RT 32m SERVER spectraViewer newfs microlab SPECTRUM ANALYZER VXI SERVER SERVER SPECTRUM ANALYZER HP8591B Figure 1 spectraViewer TCP IP connections map blew astro uni torun pl Additionally spectraViewer may communicate with the RT 32m control server for acquiring the current position of the tele scope Il CONFIGURATION The crucial configuration options for the successful program operation are the networking options located in Edit gt Preferences gt Network The relevant server IP and port combinations are stored in the combo boxes for settings of the TF servers and RT control server Use the default settings for these servers as described in Sec I Til USAGE The spectraViewer program has been installed on personal computer PC trao3 working under Linux Debian Lenny It can be star
6. first binary table is stored The contents of the individual rows are also described in the header information These include 1 JD Julian date at the time of the readout 2 RA right ascension of the RT 32 when the time of the readout deg 3 DEC declination of the RT 32 when the time of the readout deg A RT 32 azimuth counting from the North eastwards deg h RT 32 elevation deg channel IF channel 0 A 1 B 2 C 3 D 4 5 6 epoch epoch year 7 8 fa spectrum analyzer parameter 9 fe spectrum analyzer parameter 10 r spectrum analyzer parameter 11 vp spectrum analyzer parameter VI EXAMPLES A Detecting the RFI from the local radio stations Using the time averaged spectra is useful for detection of weak non transient RFI signals like radio stations An example of the integrated and single spectra displayed in the spectra view window of the spectraViewer is shown in Fig 3 aa emi wi an uh UA al My 4 IK Ali aa in lle wy m AL ala ma WW in i PE PTF ee yr is ih Frequency MHz Figure 3 Radio stations RFI as seen in spectraViewer program The radio stations signals clearly stand out in the integrated spectra blue curve above the noise levels inferred from the single spectra readout In the right panel the integration time is shown and updated The spectral features strongly coincide with the radio stations frequencies as shown in Fig 4 A
7. h 355 25 deg date 2012 04 12 19 59 65 oszcz 8 4 Radio Gra Torun Radio Plus Torun Radio Wawa Torun Radio ZET RTCN Plock RMF FM RTCN Konin Radio Eska Torun RMF Classic SLR Torun Radio Gra Bydgoszcz Radio Maryja RTCN Plock Radio ZET RTCN Konin 70 Radio Maryja RTCN Konin RMSE RTCN Bydgoszcz Radio ZET RTCN Bydgoszcz Radio dla Ciebie RTCN Plock Polskie Radio Czworka Torun P ffsie Radio Program 3 RTCN Bydgoszcz Merkury Polskie Radio RTCN Konin Polskie Radio Program 1 RTCN Plock Polskie Radio Program 3 RTCN Plock Radio Plus Bydgoszcz Bydgoszcz Polskie Radio Program 3 RTCN Konin Radio 103 5 Roxy FM Bydgoszcz E Radio Program 1 RTCN Bydgoszcz l LMCI M nl y kuh MT T Polskie Radio Program 1 RTCN Konin Power dbm i i 2 bA F Polskie Radio Program 2 RTCN Bydgoszcz a r r W 97 f MHz Figure 4 Radio stations RFI as seen in spectraViewer program The data plotted were saved to fits file and re plotted with radio stations information The date and time of the measurement was also saved in the fits file header along with the radio telescope orientation as indicated in the plot title B Observing transient RFI signals In order to trace the transient RFI signals the spectraViewer program allows for continuous recording of
8. n Tools gt store all spectra are reset and collected anew V FILES A Single spectra and average spectra FITS files data When a file is saved using File gt Save as fits command this file format will be used The header of the binary table called spectra in the first Header Data Unit HDU stores all important information about the setup including the spectrum analyzer parameters selected channel date and time of the measurement and if the Tools gt Record RT position option is checked the RT position information The contents of the binary table consists of 4 columns the first two contain the information on the last recorded single spectra and the last two contain the information on the integrated average spectra The first columns for each of the spectra types contain the frequency and the second columns contain the spectra information B All spectra FITS files data When a file is saved using File gt Save all as fits command this file format is used In this format each file contains two HDUs binary tables In the first one all collected spectra are stored while in the second one all spectrum analyzer and telescope information is stored In the first binary table in every column a full spectra from a single readout is stored The subsequent readouts are stored in columns with indexes increasing with time In the second binary table in every column the full information on the corresponding spectra from the
9. sn t supported via the spectr Viewer program It is planned that such tool will be supported in the next version of the program For no obvious reason resetting the spectrum analyzer server not always brings the hp8591b unit back to the reasonable values Few cycles of reset might be required This is an evolving issue B The data saved by spectraViewer as FITS file cannot be viewed by fv program installed on trao3 Why Get a newer fv program The data are stored correctly It is a fits file handling program problem
10. ted from the command line after logging in as oper trao3 oper trao3 S spectraViewer Figure 2 Main window of the spectraViewer program without extra features left and with extra features right Use Tools gt Show extra features option to toggle between the two views The four controllable spectrum analyzer parameters are e fa 0 MHz lower frequency limit in the viewed IF spectra e fy 1800 MHz upper frequency limit in the viewed IF spectra e r 0 dbm reference level w r t which the spectrum is calibrated By default it is 0 dbm i e Odb w r t 1 mWatt signal 1 Tn brackets the default values were given e v 3 MHz video bandwidth filter settings This controls the low pass filtering of the signal after it is detected in the spectrum analyzer The wider video bandwidth makes the output signal pass filtering less aggressive resulting in the noisier spectra but better resolving temporal narrow band spike like RFI signals The narrower video bandwidth makes the output signal low pass filtering more aggressive which results in a smoother spectra but better suited for detecting weak and relatively broad band non transient signals Since the spectraViewer allows for time averaging of the spectra and hence noise reduction for the typical use it is useful to have v as large as possible by default it is set to 3MHz In the simplified operation mode the spectraViewer allows for e acquiring the curr
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