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Message ID: 1871     Entry time: Fri Aug 18 21:34:00 2017
Author: Craig, awade 
Type: DailyProgress 
Category: PLL 
Subject: PLL OLGTF 

We took a open loop gain measurement of our PLL.

We used the Agilent 4395A to supply an excitation on the order of -35 dBm. We plugged the excitation into the B source of the SR560 preamplifier while keeping the A source the output of the low passed phase mixer, and switched the source on the SR560 to A-B.  The gain of the SR560 is two.  The Marconi was set to 98 MHz carrier with 800 kHz of FM modulation range.

OLG = o1/o2, as pictured below.  I plugged the SR560 output (the actuation signal, aka o2) into the R port on the Agilent, and plugged the SR560 input (the error signal, aka o1) into the A port, and then took the transfer function.

From the plot our UGF is at 100 kHz with 100 degrees of phase margin.

Next I need to properly calibrate the Marconi in Hz/Vrms, so I can calculate our trans beatnote spectrum in Hz/rtHz.

Attachment 1: 20170818_211017_PLL_OLGTFs.pdf  106 kB  | Hide | Hide all
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