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Message ID: 1393     Entry time: Thu Apr 14 22:59:15 2011
Author: Zach 
Type: Electronics 
Category: GYRO 
Subject: PD S/N 03 TF 

I tuned up our first TRANS PD, S/N 03, that Alastair was working on with the J-Laser tonight. Here is the TF:


As before for the REFL diodes, I measured the output node of the diode with a probe so that I could tune the readout notch to 100 MHz. I had to change C2 to 33 pF to get 100 MHz in range with the tunable cap (C4), which I changed to a 1.5-50 pF one. Here is a full-span plot and a zoom around the notch:


I think it looks ratty at high frequencies because we are starting to see interference effects from the O(1 m) length cables.

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