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AdV-DAQ (Calibration)
lagabbe - 12:06 Thursday 24 November 2022 (57887) Print this report
PCal photodiode timing measurement

The timing of photodiodes is measured,

  • The laser is switched off
  • A LED flash a signal sinchronized with the gps time in front of the photodiode, for ~1 min.
  • The LED is switched off and the laser switched on
  • A white noise signal is injected is the laser power command, for ~1 min.
  • The white noise is stopped, laser signal is back to normal

 

 

 

On NE
2022-11-24-10h47m06-UTC    info lagabbe      'PCal laser OFF:Disable laser ctrl loop' sent to NEB_PCal_fast
2022-11-24-10h47m09-UTC    info lagabbe      'PCal laser OFF:Disable laser' sent to NEB_PCal_fast
2022-11-24-10h48m10-UTC    info lagabbe      'Enable [byte=1]' sent to PCal_NE_Relay
2022-11-24-10h50m04-UTC    info lagabbe      'Disable [byte=1]' sent to PCal_NE_Relay
2022-11-24-10h50m28-UTC    info lagabbe      'PCal laser ON:Enable laser' sent to NEB_PCal_fast
2022-11-24-10h50m32-UTC    info lagabbe      'PCAL DSP filter0:Reset  [filter=0]' sent to NEB_PCal_fast
2022-11-24-10h50m33-UTC    info lagabbe      'PCAL DSP filter0:Select [filter=0]' sent to NEB_PCal_fast
2022-11-24-10h50m52-UTC    info lagabbe      'PCal laser ON:Enable laser ctrl loop' sent to NEB_PCal_fast
2022-11-24-10h51m01-UTC    info lagabbe      'PCAL noise:set noise amplitude [ramp duration=10,noise ampl=5]' sent to NEB_PCal_fast
2022-11-24-10h52m29-UTC    info lagabbe      'PCAL noise:set noise amplitude [ramp duration=10,noise ampl=0]' sent to NEB_PCal_fast
2022-11-24-10h52m47-UTC    info lagabbe      'PCAL DSP filter1:Reset [filter=1]' sent to NEB_PCal_fast
2022-11-24-10h52m49-UTC    info lagabbe      'PCAL DSP filter1:Select [filter=1]' sent to NEB_PCal_fast

 

On WE:
2022-11-24-10h53m36-UTC    info lagabbe      'PCal laser OFF:Disable laser ctrl loop' sent to WEB_PCal_fast
2022-11-24-10h53m38-UTC    info lagabbe      'PCal laser OFF:Disable laser' sent to WEB_PCal_fast
2022-11-24-10h54m04-UTC    info lagabbe      'Enable [byte=1]' sent to PCal_WE_Relay
2022-11-24-10h55m33-UTC    info lagabbe      'Disable [byte=1]' sent to PCal_WE_Relay
2022-11-24-10h55m47-UTC    info lagabbe      'PCal laser ON:Enable laser' sent to WEB_PCal_fast
2022-11-24-10h55m48-UTC    info lagabbe      'PCAL DSP filter0:Reset  [filter=0]' sent to WEB_PCal_fast
2022-11-24-10h55m51-UTC    info lagabbe      'PCAL DSP filter0:Select [filter=0]' sent to WEB_PCal_fast
2022-11-24-10h56m07-UTC    info lagabbe      'PCal laser ON:Enable laser ctrl loop' sent to WEB_PCal_fast
2022-11-24-10h56m13-UTC    info lagabbe      'PCAL noise:set noise amplitude [ramp duration=10,noise ampl=5]' sent to WEB_PCal_fast
2022-11-24-10h58m16-UTC    info lagabbe      'PCAL noise:set noise amplitude [ramp duration=10,noise ampl=0]' sent to WEB_PCal_fast
2022-11-24-10h58m37-UTC    info lagabbe      'PCAL DSP filter1:Reset [filter=1]' sent to WEB_PCal_fast

Comments to this report:
lagabbe - 17:35 Thursday 24 November 2022 (57895) Print this report

The model of the ADC channel consists in the product of:

  • a low pass butterworth filter, 5th order, with the cut off frequency 80 kHz,
  • a low pass butterworth filter, 8th order, with the cut off frequency 7499 Hz,
  • an advance of 49 µs,
  • a residual delay, which is a parameter to be fitted to the measured frequency response.

The frequency response of Tx_PD1, is measured by computing the transfers function from the excitation signal to the Tx_PD1 signal, when the LED is flashing.
The frequency response of Tx_PD2 and Rx_sphere, is measured by computing the transfers function from the Tx_PD1 signal to the Tx_PD2 or Rx_sphere signal, when the white noise is inected in laser command signal.
Values of the residual delays between the model and the measure of the frequency response of the photodiodes.

ref signal test signal delay between ref and test signals (ns) residual delay of test signal (ns)
excitation NE_Tx_PD1 699 +/- 32 699 +/- 32
NE_Tx_PD1 NE_Tx_PD2 -79 +/- 1 620 +/- 32
NE_Tx_PD1 NE_Rx_sphere 91 +/- 6 790 +/- 32
excitation WE_Tx_PD1 649 +/- 36 649 +/- 36
WE_Tx_PD1 WE_Tx_PD2 -44 +/- 1 605 +/- 36
WE_Tx_PD1 WE_Rx_sphere 879 +/- 6 1528 +/- 36

The WE_Rx sphere has a follower circuit at its output, and WE_Rx has not. The follower circuit add a delay in the frequency response.

 

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