TVEGAS_46 Bank to Bank problems with real hardware, software simulator


  • Check KATCP snaps versus Archivist snaps - Ray has already done this
  • Total power and spectrum ratios ADC / filtersnap / HPC spectra
  • Identical ratios for varying input power
  • Using the new noise source, 300MHz highpass filter, amplifier, attenuator and 8-way splitter


  • Set up in simulator at 1pm
  • switching_signal_selector is jumpered around (not sure this is necessary)
  • Set up lbw_gain. From Randy, empirically the digital filter requires a gain of 5.664 to get -20dBFS into each of real and imag separately, for a -20dBFS input.
  • So, set lbw_gain to 2**16 (unity in BOF) * 2**8 (Ray correction for old config_tool)*5.664
  • Output power for filtersnap will be -17dBFS, since real and imag powers are summed together.
  • By inspection, this is what BOF 123 produces! We have sanity...

Mode 4

  • bank_gain_mode4_cband_nocal
  • archivist
  • setValues with 5.664 (Devexplorer not working well in the simulator, can't check but looks correct.)
  • Nominal -20dBFS input corresponds to attenuator setting of -5dB
  • Cannot reset scan number
  • Scan 63 Aborts - BankE taking too long, same with 64, 65 is ok.
  • Scan 65 nominal -5dB
  • Scans 66-70, 3,4,5,6,7dB attenuation - Data look fine, but GBTIDL will only plot one polarization?

Mode 1

  • bank_gain_mode1_cband_nocal
  • archivist
  • SetValues is irrelevant
  • Attenuation of 5 now corresponds to ~ -20.3dB - stay at this value.
  • Scans 71-75, 3,4,5,6,7dB attenuation
  • 2pm - all done!

-- RichardPrestage - 2015-03-13

This topic: CICADA > WebHome > GreenBankSpectrometer > CICADAGreenBankSpectrometerCommissioningLogs > CICADAGreenBankSpectrometer2015Mar13
Topic revision: 2015-03-17, RichardPrestage
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