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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: 15774     Entry time: Wed Jan 20 18:07:09 2021     Reply to this: 15776     15780
Author: Anchal 
Type: Summary 
Category: BHD 
Subject: HAM-A Coil Driver measurements before modifications 

I have taken transfer functions and noise measurements of the two HAM-A coil driver boxes D1100687 #S2100027 and #S2100028. All transfer functions look as expected. I'm not sure about the noise measurements. If anyone sees flaw in my measurement method, please let me know. I'm not sure why in some channels I got 10Hz harmoni peaks in the noise. That was very strange. Also let me know if my current noise estimate is wrong.

Transfer Function Measurement details

  • SR785 source out was connected to the differential amplifier input of D1900068.
  • The one pair of two BNC outputs of this differential amplifier goes directly to the SR785 Input 1 A and B.
  • The DB9 output of the differential amplifier goes to the Coil Input DB9 connector J3.
  • Header W2 was shorted to provide ground to the incoming signal.
  • Header P4 was shorted to enable all the channels manually.
  • Normal operation is the Acquisition mode (Acq) while when pins of header P3 are shorted, we go into the Run mode for respective channel.
  • The “To Satellite Box” DB25 port at the read side was conencted to a DB25 breakout circuit and pins 1-9, 3-11, 5-13 and 7-15 were connected to 36 Ohm resistor to simulate Coil load.
  • The “Output Monitor” on the rear side is then connected to the test switch DB9 port on D1900068.
  • The the pair of BNCs from the test switch is connected to SR785 Input 2 A and B.
  • Measurements are taken with file D1100687_TF.yml and D1100687_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_S2100027_TF.pdf and D1100117_S2100028_TF.pdf shows all the transfer functions measured.

Spectrum Measurements

  • All channels were kept in disabled mode (Not shorting P4) to ensure their inputs are grounded on the board.
  • I ran two BNC cables with their centers connected to output monitors V2+ and V2- and one of their shields connected to board GND.
  • in SR785, A-B differential mode always runs with grounded shields mode, so effectively the board GND got grounded to SR785 GND through internal 50 Ohm resistor. But all ground loops have been evaded.
  • The two BNC cables were twisted together to minimize the area between the two center cores of the cables as that is the remaining pickoff possible in this measurement.
  • Instrument noise with cables was measured first but shorting the clips of the center cores and one of the shields of the two BNC cables together.
  • Measurements were taken with file D1100687_SP.yml and D1100687_SP_LF.yml.
  • D1100117_S2100027_Voltage_Noise_Spectrum.pdf and D1100117_S2100028_Voltage_Noise_Spectrum.pdf shows the measured voltage noise spectrum at the output monitors when loaded with 36 Ohms.
  • D1100117_S2100027_Current_Noise_Spectrum.pdf and D1100117_S2100028_Current_Noise_Spectrum.pdf shows the esitmate current noise through the coil calculated by dividing the measured voltage noise by 2436 Ohms.
Attachment 1: MeasurementData.zip  2.666 MB
Attachment 2: D1100117_S2100027_TF.pdf  69 kB  | Hide | Hide all
D1100117_S2100027_TF.pdf D1100117_S2100027_TF.pdf D1100117_S2100027_TF.pdf D1100117_S2100027_TF.pdf D1100117_S2100027_TF.pdf
Attachment 3: D1100117_S2100028_TF.pdf  69 kB  | Hide | Hide all
D1100117_S2100028_TF.pdf D1100117_S2100028_TF.pdf D1100117_S2100028_TF.pdf D1100117_S2100028_TF.pdf D1100117_S2100028_TF.pdf
Attachment 4: D1100117_S2100027_Voltage_Noise_Spectrum.pdf  276 kB  | Hide | Hide all
D1100117_S2100027_Voltage_Noise_Spectrum.pdf D1100117_S2100027_Voltage_Noise_Spectrum.pdf D1100117_S2100027_Voltage_Noise_Spectrum.pdf D1100117_S2100027_Voltage_Noise_Spectrum.pdf D1100117_S2100027_Voltage_Noise_Spectrum.pdf
Attachment 5: D1100117_S2100028_Voltage_Noise_Spectrum.pdf  276 kB  | Hide | Hide all
D1100117_S2100028_Voltage_Noise_Spectrum.pdf D1100117_S2100028_Voltage_Noise_Spectrum.pdf D1100117_S2100028_Voltage_Noise_Spectrum.pdf D1100117_S2100028_Voltage_Noise_Spectrum.pdf D1100117_S2100028_Voltage_Noise_Spectrum.pdf
Attachment 6: D1100117_S2100027_Current_Noise_Spectrum.pdf  277 kB  | Hide | Hide all
D1100117_S2100027_Current_Noise_Spectrum.pdf D1100117_S2100027_Current_Noise_Spectrum.pdf D1100117_S2100027_Current_Noise_Spectrum.pdf D1100117_S2100027_Current_Noise_Spectrum.pdf D1100117_S2100027_Current_Noise_Spectrum.pdf
Attachment 7: D1100117_S2100028_Current_Noise_Spectrum.pdf  276 kB  | Hide | Hide all
D1100117_S2100028_Current_Noise_Spectrum.pdf D1100117_S2100028_Current_Noise_Spectrum.pdf D1100117_S2100028_Current_Noise_Spectrum.pdf D1100117_S2100028_Current_Noise_Spectrum.pdf D1100117_S2100028_Current_Noise_Spectrum.pdf
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