mg002

    Version as of 08:26, 25 Nov 2024

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    MG002 Correlation Report

    General:

    • Session info: http://www3.mpifr-bonn.mpg.de/div/vlbi/globalmm/
    • Station feedback: http://www3.mpifr-bonn.mpg.de/div/vlbi/globalmm/sessions/apr17/feedback_apr17.asc
    • ALMA QA2: 2016.1.01116.V was used for polarization conversion
    • This experiment has ALMA with 32x62.5MHz, VLBA with 2x128MHz channels, and most of the EVN with a 1x512MHz channel
    • Two EVN stations (Yebes, Pico Veleta) observed in an incorrect backend mode, with a 32 MHz polyphase filterbank.
    • Due to the issue at Yebes and Pico, three correlations were performed:
      • a) standard ALMA correlation setup (58 MHz bands) discarding Yebes and Pico
      • b) narrower band correlation setup (32 MHz bands) including Yebes and Pico
      • c) mixed-band correlation with additional postprocessing of all baselines to Yebes and Pico Veleta (reconstructed 58 MHz bands)
    • The correlation output (c) appears correct, but uses a new feature that has not been vigorously tested. The data are provided without guarantees. Details are given further below.

    Fringes:

    Station Fringes Comment
    Ef yes Effelsberg DBBC2
    Eb yes Effelsberg RDBE
    On yes  
    Aa yes  
    Mh no faulty backend configuration
    Pv yes LCP bad (2bit sample dist. 78%:0:0:22%), is OK in ma008 and mb007
    Ys yes  
    Fd yes  
    La yes  
    Pt yes weak or no fringes
    Nl yes  
    La yes  
    Kp yes  
    Ov yes  
    Mk no  
    Br yes  

    Fringes plotted on all baselines to Effelserg (No0134 Effelsberg PDF), and ALMA (No0140 ALMA PDF).

    Notes:

    1. PV scan: /mnt/disks/4/7/data/ma008_PV_093-2145.vdif marked invalid by vdifuse
    2. PV: bad statistics before 092-2100 (OK after systems was restarted at Pico)
    3. PV: DBBC2 backend ran in polyphase filter bank mode, data are 16 ch x 2 pol x 32 MHz
    4. YS: DBBC2 backend ran in polyphase filter bank mode, data are 16 ch x 2 pol x 32 MHz
    5. MH: Autoccorelations look corrupted. Suspicous of 32 MHz sub-bands displayed as full band: So far no fringes, except for LCP (weak) in Scan No064. (MM-LCP.ps     MM-RCP.ps)
    6. VLBA: subintNS has to be choosen to be 640000 when adding in VLBA (and EB) having 128 MHz wide subbands. If run with the default settings an WARNING concerning "data gaps" is received and no data is being correlated.

    Auxiliary:

    The exact zoom bands after matching ALMA constraints against Pico/Yebes 32 MHz PFB bands, without yet considering extra coverage of the 1x512MHz  and 2x256MHz of other stations, are:

    addZoomFreq = freq@86508.000000/bw@32.000000/noparent@true  # ALMA ch11 x Pico ch00
    addZoomFreq = freq@86476.000000/bw@28.328125/noparent@true  # ALMA ch12 x Pico ch01
    addZoomFreq = freq@86444.000000/bw@32.000000/noparent@true  # ALMA ch12 x Pico ch02
    addZoomFreq = freq@86444.000000/bw@1.734375/noparent@true  # ALMA ch13 x Pico ch02
    addZoomFreq = freq@86412.000000/bw@32.000000/noparent@true  # ALMA ch13 x Pico ch03
    addZoomFreq = freq@86380.000000/bw@7.140625/noparent@true  # ALMA ch14 x Pico ch04
    addZoomFreq = freq@86348.000000/bw@32.000000/noparent@true  # ALMA ch14 x Pico ch05
    addZoomFreq = freq@86316.000000/bw@12.546875/noparent@true  # ALMA ch15 x Pico ch06
    addZoomFreq = freq@86284.000000/bw@32.000000/noparent@true  # ALMA ch15 x Pico ch07
    addZoomFreq = freq@86252.000000/bw@17.953125/noparent@true  # ALMA ch16 x Pico ch08
    addZoomFreq = freq@86220.000000/bw@32.000000/noparent@true  # ALMA ch16 x Pico ch09
    addZoomFreq = freq@86188.000000/bw@23.359375/noparent@true  # ALMA ch17 x Pico ch10
    addZoomFreq = freq@86156.000000/bw@32.000000/noparent@true  # ALMA ch17 x Pico ch11
    addZoomFreq = freq@86124.000000/bw@28.765625/noparent@true  # ALMA ch18 x Pico ch12
    addZoomFreq = freq@86092.000000/bw@32.000000/noparent@true  # ALMA ch18 x Pico ch13
    addZoomFreq = freq@86092.000000/bw@2.171875/noparent@true  # ALMA ch19 x Pico ch13
    addZoomFreq = freq@86060.000000/bw@32.000000/noparent@true  # ALMA ch19 x Pico ch14
    addZoomFreq = freq@86028.000000/bw@7.578125/noparent@true  # ALMA ch20 x Pico ch15
    

    The above correlates fine in DiFX but difx2fits and difx2mark4 error out at the unequal bandwidths. One equal-bandwidth option with 9 x  32 MHz is:

    addZoomFreq = freq@86508.000000/bw@32.000000/noparent@true  # ALMA ch11 x Pico ch00
    addZoomFreq = freq@86444.000000/bw@32.000000/noparent@true  # ALMA ch12 x Pico ch02
    addZoomFreq = freq@86412.000000/bw@32.000000/noparent@true  # ALMA ch13 x Pico ch03
    addZoomFreq = freq@86348.000000/bw@32.000000/noparent@true  # ALMA ch14 x Pico ch05
    addZoomFreq = freq@86284.000000/bw@32.000000/noparent@true  # ALMA ch15 x Pico ch07
    addZoomFreq = freq@86220.000000/bw@32.000000/noparent@true  # ALMA ch16 x Pico ch09
    addZoomFreq = freq@86156.000000/bw@32.000000/noparent@true  # ALMA ch17 x Pico ch11
    addZoomFreq = freq@86092.000000/bw@32.000000/noparent@true  # ALMA ch18 x Pico ch13
    addZoomFreq = freq@86060.000000/bw@32.000000/noparent@true  # ALMA ch19 x Pico ch14
    

    The VEX file info for Yebes and Pico are new $FREQ and $TRACK as below:

    def FREQ_PFB;
         sample_rate = 64.00 Ms/sec;  * (2bits/sample)
       chan_def = : 86540.00 MHz : L : 32.00 MHz : &CH01 : &BBC01 : &NoCal; *Rcp
       chan_def = : 86540.00 MHz : L : 32.00 MHz : &CH02 : &BBC02 : &NoCal; *Lcp
       chan_def = : 86508.00 MHz : L : 32.00 MHz : &CH03 : &BBC03 : &NoCal; *Rcp
       chan_def = : 86508.00 MHz : L : 32.00 MHz : &CH04 : &BBC04 : &NoCal; *Lcp
       chan_def = : 86476.00 MHz : L : 32.00 MHz : &CH05 : &BBC05 : &NoCal; *Rcp
       chan_def = : 86476.00 MHz : L : 32.00 MHz : &CH06 : &BBC06 : &NoCal; *Lcp
       chan_def = : 86444.00 MHz : L : 32.00 MHz : &CH07 : &BBC07 : &NoCal; *Rcp
       chan_def = : 86444.00 MHz : L : 32.00 MHz : &CH08 : &BBC08 : &NoCal; *Lcp
       chan_def = : 86412.00 MHz : L : 32.00 MHz : &CH09 : &BBC09 : &NoCal; *Rcp
       chan_def = : 86412.00 MHz : L : 32.00 MHz : &CH10 : &BBC10 : &NoCal; *Lcp
       chan_def = : 86380.00 MHz : L : 32.00 MHz : &CH11 : &BBC11 : &NoCal; *Rcp
       chan_def = : 86380.00 MHz : L : 32.00 MHz : &CH12 : &BBC12 : &NoCal; *Lcp
       chan_def = : 86348.00 MHz : L : 32.00 MHz : &CH13 : &BBC13 : &NoCal; *Rcp
       chan_def = : 86348.00 MHz : L : 32.00 MHz : &CH14 : &BBC14 : &NoCal; *Lcp
       chan_def = : 86316.00 MHz : L : 32.00 MHz : &CH15 : &BBC15 : &NoCal; *Rcp
       chan_def = : 86316.00 MHz : L : 32.00 MHz : &CH16 : &BBC16 : &NoCal; *Lcp
       chan_def = : 86284.00 MHz : L : 32.00 MHz : &CH17 : &BBC17 : &NoCal; *Rcp
       chan_def = : 86284.00 MHz : L : 32.00 MHz : &CH18 : &BBC18 : &NoCal; *Lcp
       chan_def = : 86252.00 MHz : L : 32.00 MHz : &CH19 : &BBC19 : &NoCal; *Rcp
       chan_def = : 86252.00 MHz : L : 32.00 MHz : &CH20 : &BBC20 : &NoCal; *Lcp
       chan_def = : 86220.00 MHz : L : 32.00 MHz : &CH21 : &BBC21 : &NoCal; *Rcp
       chan_def = : 86220.00 MHz : L : 32.00 MHz : &CH22 : &BBC22 : &NoCal; *Lcp
       chan_def = : 86188.00 MHz : L : 32.00 MHz : &CH23 : &BBC23 : &NoCal; *Rcp
       chan_def = : 86188.00 MHz : L : 32.00 MHz : &CH24 : &BBC24 : &NoCal; *Lcp
       chan_def = : 86156.00 MHz : L : 32.00 MHz : &CH25 : &BBC25 : &NoCal; *Rcp
       chan_def = : 86156.00 MHz : L : 32.00 MHz : &CH26 : &BBC26 : &NoCal; *Lcp
       chan_def = : 86124.00 MHz : L : 32.00 MHz : &CH27 : &BBC27 : &NoCal; *Rcp
       chan_def = : 86124.00 MHz : L : 32.00 MHz : &CH28 : &BBC28 : &NoCal; *Lcp
       chan_def = : 86092.00 MHz : L : 32.00 MHz : &CH29 : &BBC29 : &NoCal; *Rcp
       chan_def = : 86092.00 MHz : L : 32.00 MHz : &CH30 : &BBC30 : &NoCal; *Lcp
       chan_def = : 86060.00 MHz : L : 32.00 MHz : &CH31 : &BBC31 : &NoCal; *Rcp
       chan_def = : 86060.00 MHz : L : 32.00 MHz : &CH32 : &BBC32 : &NoCal; *Lcp
    enddef;
    ...
    def VDIF.PvPFB;
         track_frame_format = VDIF_5032-4096-32-2;  * Pico
         *track_frame_format = VDIF_8032-4096-32-2; * Yebes
         fanout_def =   : &CH01  : sign : 1: 1;
         fanout_def =   : &CH01  :  mag : 1: 1;
         fanout_def =   : &CH02  : sign : 1: 2;
         fanout_def =   : &CH02  :  mag : 1: 2;
         fanout_def =   : &CH03  : sign : 1: 3;
         fanout_def =   : &CH03  :  mag : 1: 3;
         fanout_def =   : &CH04  : sign : 1: 4;
         fanout_def =   : &CH04  :  mag : 1: 4;
         fanout_def =   : &CH05  : sign : 1: 5;
         fanout_def =   : &CH05  :  mag : 1: 5;
         fanout_def =   : &CH06  : sign : 1: 6;
         fanout_def =   : &CH06  :  mag : 1: 6;
         fanout_def =   : &CH07  : sign : 1: 7;
         fanout_def =   : &CH07  :  mag : 1: 7;
         fanout_def =   : &CH08  : sign : 1: 8;
         fanout_def =   : &CH08  :  mag : 1: 8;
         fanout_def =   : &CH09  : sign : 1: 9;
         fanout_def =   : &CH09  :  mag : 1: 9;
         fanout_def =   : &CH10  : sign : 1: 10;
         fanout_def =   : &CH10  :  mag : 1: 10;
         fanout_def =   : &CH11  : sign : 1: 11;
         fanout_def =   : &CH11  :  mag : 1: 11;
         fanout_def =   : &CH12  : sign : 1: 12;
         fanout_def =   : &CH12  :  mag : 1: 12;
         fanout_def =   : &CH13  : sign : 1: 13;
         fanout_def =   : &CH13  :  mag : 1: 13;
         fanout_def =   : &CH14  : sign : 1: 14;
         fanout_def =   : &CH14  :  mag : 1: 14;
         fanout_def =   : &CH15  : sign : 1: 15;
         fanout_def =   : &CH15  :  mag : 1: 15;
         fanout_def =   : &CH16  : sign : 1: 16;
         fanout_def =   : &CH16  :  mag : 1: 16;
         fanout_def =   : &CH17  : sign : 1: 17;
         fanout_def =   : &CH17  :  mag : 1: 17;
         fanout_def =   : &CH18  : sign : 1: 18;
         fanout_def =   : &CH18  :  mag : 1: 18;
         fanout_def =   : &CH19  : sign : 1: 19;
         fanout_def =   : &CH19  :  mag : 1: 19;
         fanout_def =   : &CH20  : sign : 1: 20;
         fanout_def =   : &CH20  :  mag : 1: 20;
         fanout_def =   : &CH21  : sign : 1: 21;
         fanout_def =   : &CH21  :  mag : 1: 21;
         fanout_def =   : &CH22  : sign : 1: 22;
         fanout_def =   : &CH22  :  mag : 1: 22;
         fanout_def =   : &CH23  : sign : 1: 23;
         fanout_def =   : &CH23  :  mag : 1: 23;
         fanout_def =   : &CH24  : sign : 1: 24;
         fanout_def =   : &CH24  :  mag : 1: 24;
         fanout_def =   : &CH25  : sign : 1: 25;
         fanout_def =   : &CH25  :  mag : 1: 25;
         fanout_def =   : &CH26  : sign : 1: 26;
         fanout_def =   : &CH26  :  mag : 1: 26;
         fanout_def =   : &CH27  : sign : 1: 27;
         fanout_def =   : &CH27  :  mag : 1: 27;
         fanout_def =   : &CH28  : sign : 1: 28;
         fanout_def =   : &CH28  :  mag : 1: 28;
         fanout_def =   : &CH29  : sign : 1: 29;
         fanout_def =   : &CH29  :  mag : 1: 29;
         fanout_def =   : &CH30  : sign : 1: 30;
         fanout_def =   : &CH30  :  mag : 1: 30;
         fanout_def =   : &CH31  : sign : 1: 31;
         fanout_def =   : &CH31  :  mag : 1: 31;
         fanout_def =   : &CH32  : sign : 1: 32;
         fanout_def =   : &CH32  :  mag : 1: 32;
    enddef;
    *