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Size: 1982
Comment:
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Size: 2176
Comment:
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| == Thermal compensation LPF == === circuit diagram === attachment:thermalLPF.png === expected transfer function of composed frequency actuator === attachment:thermal_actuator.png [[BR]] ----- |
Electronics
outline
- Preliminary design for the electronics used in 40m green locking.
VCO
Filter respons
- 80MHz LIGO VCO box is used to readout the frequency of the beat signal precisely.
Noise performance
lock detection and boost
- rms detection
PDH box
Filter Shape
=== Noise performance ==
LPF for RF cutoff
Low frequency mixer
Remotely controlled Boost switch
frequency counter
- SR620 is employed to read out the frequency of the beat signal.
attachment:SR620.png
setting parameters |
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readout range |
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MHz |
DAC bit resolution |
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noise |
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digital channel assign
whitening filter
- what is the specification for each channel
wideband RFPD for green PLL
- A Silicon photodiode with the diameter of 10mm is used. To have a fast response up to about 1MHz -150V is applied onto the photo diode.
The schematic is available on [https://nodus.ligo.caltech.edu:30889/svn/trunk/alberto/40mUpgrade/RFsystem/RFPDs/GreenLockingBroadBandPD svn]
frequency response
attachment:RFPD_tf.png
noise performance
attachment:RFPDnoise.png
Here is the noise model for the RFPD using liso. attachment:liso_RFPD.png
DC PDs
PDA36A
- attachment:PDA36A.png
parameters |
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trans impedance gain |
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[V/A] |
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responsibility |
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[A/W] |
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quantum efficiency |
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[%] |
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digital front end
- anti-aliasing filter
- anti-imaging filter
Thermal compensation LPF
circuit diagram
attachment:thermalLPF.png
expected transfer function of composed frequency actuator
attachment:thermal_actuator.png
Power Supply and Cables
HV cables (-150V) for photodiode bias