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Message ID: 1805     Entry time: Sun Jan 8 14:43:50 2017
Author: yinzi 
Type: DailyProgress 
Category: TempCtrl 
Subject: circuit board update and measurements 

Andrew switched out the bypass capacitors to ceramic ones over break. Now all of the channels are functional, so I guess that was the problem (I don't know what the physical problem would have been before, though).

Here are some measurements of the frequency response.

Channel 1

Channel 2

Channel 3

Here's the noise. I don't know why it has the "edges", I'm pretty sure I made the measurements the same way as I was doing before and used the same stiching script... I might repeat these measurements later, but it's at least an idea.

Channel 1 has much higher noise. Possibly because there are power lines that cross over the area, whereas for 2 and 3 the power lines are routed from the side? Could be another reason though...

Data and scripts attached.

Attachment 5: plots_01082017.m  1 kB  | Hide | Hide all
%another plotting script
%sorry the numbering is all out of order
%1-2 mag and phase channel 2
%3 - phase channel 3
%4 - phase channel 1
%5 - mag channel 1
%6 - mag channel 3
%7-10 noise channel 3
%11-14 noise channel 2
%15-18 noise channel 1
... 52 more lines ...
Attachment 6: freqStitch.m  3 kB  | Hide | Hide all
%%  This is a module for stiching spans of overlapping PSDs of different frequency bin size from SR785
%   Assuming a logerithmic scale of frequency, it is desirable to 
%   stich the smaller frequecy ranges to the bottom of the larger ones
%   wilst truncating out bins in the larger span.
%Feed in frequency matrix f(n,m) with correesponding floating point
%%  Synopsis:
%     [freqStitch,dataStitch] = freqStitch(freqPoints,dataPoints)
... 62 more lines ...
Attachment 7: data_array.mat  99 kB
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