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Message ID: 391     Entry time: Thu Nov 11 22:50:14 2010
Author: tara 
Type: DailyProgress 
Category: BEAT 
Subject: beat noise measurement 

I measured the beat note signal from two different setup (f modulation) and plot the result below


We want to see where our beat signal is, and compare it to the noise budget, and improve the sensitivity.

I'm using the same noise budget for now, because

my noise model from RIN has not been finished yet. I'll try to finish it soon.


For beat measurement, I measured the feedback signal of the PLL loop,

since the UGF of the loop, which is 53 kHz, covers the region of our interest.


I used two frequency span on marconi, 20 kHz and 100 kHz.

I checked the calibration for each frequency spans which are 14.31 kHz/V and 70.8 kHz/V respectively.

The results are the same at low f to ~ 200 Hz, at higher f, 20 kHz span(brown line) has better sensitivity.


*b100 and b20 in the data.mat files are the result of beat at fmod 100kHz and 20 kHz in the format of

frequency, V/rtHz , f / rtHz





power input: 16mW

V_RF: 5.7 V

Phase ADj: 2.23 V

Gain: 13 dB



power input: 2.86 mW

V_RF: 10

Phase ADJ: 4.2 V

Common gain: 18.9 dB

Fast Gain: 20 dB



power input: 2.0 mW

Attachment 1: psl_refcav_sio2_300K.png  62 kB  | Hide | Hide all
Attachment 2: data.mat  64 kB
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