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== Low frequency mixer ==
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== Low frequency mixer ==
 . ZAD-8 from mini circuit

outline

  • Preliminary design for the electronics used in 40m green locking.

electronics_diagram.png

Contents

  1. outline
  2. VCO for frequency tracking
    1. VCO range
    2. Filter respons
    3. Noise performance
    4. lock detection and boost
  3. PDH box
    1. Filter Shape
    2. Noise performance
    3. LPF for RF cutoff
    4. Remotely controlled Boost switch
  4. frequency counter
  5. digital channel assign
  6. wideband RFPD for green PLL
    1. frequency response
    2. noise performance
  7. DC PDs
    1. PDA36A
  8. Thermal feedback LPF
    1. circuit diagram
    2. expected transfer function of composed frequency actuator
  9. Function Generator
  10. Summing Amplifier
    1. Diagram
    2. noise performance
  11. Temperature Controller for doubling oves
  12. RF stuff
    1. low noise amplifier
    2. mid power amplifier
    3. power splitter
    4. DC block
    5. Low frequency mixer
  13. Power Supply and Cables
    1. HV cables (-150V) for photodiode bias
    2. 15V and 24V lines

BR BR

VCO for frequency tracking

VCO range

  • Synergy VCO part number XXX has 1.2MHz/V VCO range.

attachment:VCO_range.png

Filter respons

  • 80MHz LIGO VCO box is used to readout the frequency of the beat signal precisely.

attachment:VCO_filter.png

Noise performance

lock detection and boost

  • rms detection

BR

PDH box

Filter Shape

attachment:TF_PDH.png

Noise performance

LPF for RF cutoff

Remotely controlled Boost switch

BR

frequency counter

  • SR620 is employed to read out the frequency of the beat signal.

attachment:SR620.png

setting parameters

readout range

MHz

DAC bit resolution

noise

BR

digital channel assign

green_digital.png

BR

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

BR

DC PDs

PDA36A

  • attachment:PDA36A.png

parameters

trans impedance gain

[V/A]

responsibility

[A/W]

quantum efficiency

[%]

BR

= digital front end filters=

  • anti-aliasing filter
  • anti-imaging filter
  • whitening filter

BR

Thermal feedback LPF

circuit diagram

attachment:thermalLPF.png

expected transfer function of composed frequency actuator

attachment:thermal_actuator.png

BR

Function Generator

  • To get a phase modulation imposed on the end IR lasers, a function generator is needed.

SR___

BR

Summing Amplifier

In order to send a feedback signal and modulation signal to the laser PZT, it is desired to have a summing amplifier. The amplifier should handle the signal from DC to 200kHz.

Diagram

noise performance

BR

Temperature Controller for doubling oves

. TC200 from Thorlabs

BR

RF stuff

low noise amplifier

mid power amplifier

power splitter

DC block

Low frequency mixer

  • ZAD-8 from mini circuit

BR

Power Supply and Cables

HV cables (-150V) for photodiode bias

15V and 24V lines

Advanced_Techniques/Green_Locking/Electronics (last edited 2017-04-20 01:58:36 by RanaadhikariATligoDOTorg)