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Entry  Wed Jan 20 18:07:09 2021, Anchal, Summary, BHD, HAM-A Coil Driver measurements before modifications 7x
    Reply  Mon Jan 25 18:18:04 2021, Anchal, Summary, BHD, Satellite Amplifier Transfer Functions and noise D1002818_S2100029_TFandNoiseSpectrum.pdfD1002818_Testing.zip
       Reply  Wed Feb 3 16:27:19 2021, Anchal, Summary, BHD, Satellite Amplifier Transfer Functions and noise After modifications D1002818_S2100029_TFAfterChanges.pdfD1002818_S2100029_OutputNoiseSpecAfterChanges.pdfD1002818_S2100029_InputRefferedNoiseSpecAfterChanges.pdfD1002812_S2100029_After_Modifications_Feb3.jpgAfterChanges.zip
          Reply  Wed Feb 10 11:45:59 2021, Anchal, Summary, BHD, Satellite Amplifier Very Low frequency noise After modifications 6x
             Reply  Wed Feb 10 15:07:50 2021, Anchal, Summary, BHD, Satellite Amplifier Output Offset measurements 
                Reply  Wed Feb 10 15:25:45 2021, gautam, Summary, BHD, Satellite Amplifier Output Offset measurements 
                   Reply  Wed Feb 10 17:18:03 2021, Koji, Summary, BHD, Satellite Amplifier Output Offset measurements 
             Reply  Thu Feb 11 11:10:05 2021, Anchal, Summary, BHD, Satellite Amplifier Very Low frequency noise After modifications AfterChangesSpectrum_AC.zipD1002818_S2100029_OutputNoiseSpecAfterChanges.pdfD1002818_S2100029_InputRefCurrentNoiseSpecAfterChanges.pdfD1002818_S2100029_InputRefDispNoiseSpecAfterChanges.pdf
                Reply  Thu Feb 11 16:58:52 2021, rana, Summary, BHD, Satellite Amplifier Very Low frequency noise After modifications 
    Reply  Thu Jan 28 12:53:14 2021, Anchal, Summary, BHD, HAM-A Coil Driver measurements before modifications D1100117_S2100027_Current_Noise_Spectrum.pdfD1100117_S2100027_Voltage_Noise_Spectrum.pdfD1100117_S2100028_Current_Noise_Spectrum.pdfD1100117_S2100028_Voltage_Noise_Spectrum.pdfSpectrumMeasurement.zip
       Reply  Thu Jan 28 18:04:55 2021, Anchal, Summary, BHD, HAM-A Coil Driver measurements After modifications D1100117_S2100027_TF.pdfAfterChanges.zip
          Reply  Thu Jan 28 21:44:45 2021, gautam, Summary, BHD, HAM-A Coil Driver measurements After modifications 
             Reply  Fri Jan 29 15:39:30 2021, Anchal, Summary, BHD, HAM-A Coil Driver measurements After modifications TF and Noise S2100027 D1100687_S2100027_After_Modifications_Jan28.jpgD1100117_S2100027_TF.pdfD1100117_S2100027_Voltage_Noise_Spectrum.pdfD1100117_S2100027_Current_Noise_Spectrum.pdfAfterChanges.zip
                Reply  Tue Feb 2 11:57:46 2021, Anchal, Summary, BHD, HAM-A Coil Driver measurements After modifications TF and Noise S2100028 D1100687_S2100028_After_Modifications_Feb01_2021.jpgD1100117_S2100028_TF.pdfD1100117_S2100028_Voltage_Noise_Spectrum.pdfD1100117_S2100028_Current_Noise_Spectrum.pdfAfterChanges.zip
Message ID: 15776     Entry time: Mon Jan 25 18:18:04 2021     In reply to: 15774     Reply to this: 15793
Author: Anchal 
Type: Summary 
Category: BHD 
Subject: Satellite Amplifier Transfer Functions and noise 

 

I took transfer function and noise measurement of satellite amplifier box's photodiode transimpedance circuit. For the measurement, I created a makeshift connector to convert backside DB25 into DB9 with the 4 channels for PDA input. The output was taken in differential form at the front PD Output port. To feed current to the circuit, I put in 12 kOhm resistors in series at the inputs, so the V/V transfer function measured was multiplied by 12 kOhm to get the transimpedance of the circuit.


Transfer Function Measurement details

  • SR785 source out was fed into PDA input pins using a makeshift BNC-DB9-DB25 converter.
  • The output from PDOut DB9 port was fed to test switch in D1900068 to separate differential signal.
  • This differential signal was fed back to SR785 at input 2 in A-B configuration.
  • Measurements are taken with file D1002818_TF.yml and D1002818_TF_LF.yml.
  • A measurement of just cables without the DUT is taken as well.
  • Commands.txt list all the commands used.
  • All data is compiled and plotted in Plotting.ipynb
  • D1100117_S2100029_TFandNoiseSpectrum.pdf shows all the transfer functions measured.

Spectrum Measurements

  • Two pair of BNC cables were twisted together and clips were added at ends.
  • One of the GND was connected to board GND. Rest were left unconnected to avoid ground loops.
  • Each pair of signal was connected to PDOutP/N.
  • The PDA inputs were shorted together to make zero input current to the board.
  • Instrument noise with cables was measured by shorting the clips of the center cores and one of the shields of the two BNC cables together.
  • Measurements were taken with file D1002818_SP.yml and D1002818_SP_LF.yml.
  • Input referred current noise spectrum was calculated by dividing the output voltage noise spectrum by the measured transfer function.
  • D1100117_S2100029_TFandNoiseSpectrum.pdf shows all the output votlage noise spectrum and input referred current noise spectrum measured.

Edit Wed Feb 10 15:14:13 2021 :

THE NOISE MEASUREMENT WAS WRONG HERE. SEE 40m/15799.

Attachment 1: D1002818_S2100029_TFandNoiseSpectrum.pdf  241 kB  | Hide | Hide all
D1002818_S2100029_TFandNoiseSpectrum.pdf D1002818_S2100029_TFandNoiseSpectrum.pdf D1002818_S2100029_TFandNoiseSpectrum.pdf
Attachment 2: D1002818_Testing.zip  1.326 MB  Uploaded Tue Jan 26 10:34:10 2021
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