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== Open loop transfer function ==
Measured on 22 Dec 2015, with the average level of green transmission at 0.457.
{{attachment:Y_PDH_OLTF.pdf||width=700}}

Overview of green electronics

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

Upgrade 09/GreenLock/Electronics/electronics_diagram

Contents

  1. Overview of green electronics
  2. VCO for frequency tracking
    1. VCO range
    2. Filter respons
    3. Noise performance
    4. Capture range and Lock range
    5. lock detection and boost
  3. PDH box
    1. Filter Shape
    2. Open loop transfer function
    3. Noise performance
    4. LPF for RF cutoff
    5. 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. digital front end filters
  9. Thermal feedback LPF
    1. circuit diagram
    2. expected transfer function of compound frequency actuator
  10. Function Generator
  11. Summing Amplifier
    1. Diagram
    2. noise performance
  12. Temperature Controller for doubling oves
  13. RF stuff
    1. low noise amplifier
    2. mid power amplifier
    3. power splitter
    4. DC block
    5. Low frequency mixer
  14. RS232 serial device server
  15. Vertex BeatBox



VCO for frequency tracking

VCO range

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

VCO_range.png

Filter respons

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

VCO_filter.png

Noise performance

Capture range and Lock range

  • According to a simple calculations...

lock detection and boost

  • rms detection


PDH box

Filter Shape

TF_PDH.png

Open loop transfer function

Measured on 22 Dec 2015, with the average level of green transmission at 0.457. Y_PDH_OLTF.pdf

Noise performance

LPF for RF cutoff

Remotely controlled Boost switch


frequency counter

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

SR620.png

setting parameters

readout range

MHz

DAC bit resolution

noise


digital channel assign

Upgrade 09/GreenLock/Electronics/digital_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 svn

attachment:Hartmut_RFPD.jpg

frequency response

RFPD_tf.png

noise performance

RFPDnoise.png

Here is the noise model for the RFPD using liso.


DC PDs

PDA36A

  • PDA36A.png

The PDA36A is an amplified, switchable-gain, silicon detector designed for detection of light signals over 350 – 1100nm wavelength range.

parameters

Detector

Si PIN

trans impedance gain

1.5k - 475k (switchable)

[V/A]

responsibility

0.3

[A/W] at 532 nm

output impedance

50

[Ohm]

Output Voltage

0-5

[V] with 50 Ohm termination

Band Width

17

[MHz]

Dark noise

nV/sqrtHz


digital front end filters

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


Thermal feedback LPF

circuit diagram

thermalLPF.png

expected transfer function of compound frequency actuator

thermal_actuator.png


Function Generator

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

SR___


Summing Amplifier

In order to send a feedback signal and modulation signal to the laser PZT at the same time, it is desired to have a summing amplifier. The amplifier should handle the signal from DC to 200kHz. Currently this is taken place by SR560.

Diagram

noise performance


Temperature Controller for doubling oves

  • TC200 from Thorlabs

  • tc200.jpg


RF stuff

low noise amplifier

  • ZFL-1000 from mini circuit or similar families

  • zfl1000.png

mid power amplifier

power splitter

  • ZFRSC-42 from mini circuit. DC-4.2GHz

  • k18.jpg

DC block

  • BLK-89 from mini circuit. 50 Ohm, 100kHz-8GHz

  • ff888.jpg

Low frequency mixer

  • ZAD-8 from mini circuit. 500Hz-10MHz.

  • m22.jpg


RS232 serial device server

Vertex BeatBox

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