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Entry  Fri Sep 4 20:42:14 2015, gautam, rana, Update, CDS, Checkout of the Wenzel dividers TEK00000.PNGTEK00001.PNGTEK00002.PNG
    Reply  Tue Sep 29 03:14:04 2015, gautam, Update, CDS, Frequency divider box IMG_0014.JPGIMG_0015.JPG
       Reply  Fri Oct 9 19:54:58 2015, gautam, Update, CDS, Frequency divider box - installation in 1X2 rack IMG_0027.JPGtime_seris_25MHz.pdf
          Reply  Mon Oct 12 17:04:02 2015, gautam, Update, CDS, Frequency divider box - further tests calibration.pdfsystematics.pdf
             Reply  Wed Oct 14 17:40:50 2015, gautam, Update, CDS, Frequency divider box - further tests time_series_input_signals.pdfcalibration_20151012.pdfsystematics_20151012.pdf
                Reply  Tue Oct 20 17:36:01 2015, gautam, Update, CDS, Frequency counting with moving average 
                   Reply  Fri Oct 23 18:36:48 2015, gautam, Update, CDS, Frequency counting - workable setup prepared Yscan.pdf
                      Reply  Fri Oct 23 19:27:19 2015, Koji, Update, CDS, Frequency counting - workable setup prepared 
                         Reply  Sat Oct 24 12:34:43 2015, gautam, Update, CDS, Frequency counting - workable setup prepared Yscan.pdfFrequency_readout.pdf
                      Reply  Thu Nov 5 03:04:13 2015, gautam, Update, CDS, Frequency counting - systematics and further changes Systematic_error.pdfsystematics_origin.pdf
Message ID: 11710     Entry time: Fri Oct 23 19:27:19 2015     In reply to: 11709     Reply to this: 11712
Author: Koji 
Type: Update 
Category: CDS 
Subject: Frequency counting - workable setup prepared 

It is a nice scan. I'm still thinking about the equivalence of the moving average and the FIR low pass that I have mentioned in the meeting.

Anyways:

I'm confused by the plot. The bottom axis says "green beat frequency".
If you scan the IR laser frequency by df, you get 2*df shift of the green beatnote. You need to have this factor of two somewhere.
If you are looking at the IR beat freq, just the label is not correct. (I believe this is the case.)

Accepting the rather-too-low finesse of 363 (nominally 450), the total round trip loss is said to be 0.0173.
If we subtract the front transmission of 1.38% (and ignoring the transmission loss from the ETM),
the round trip loss is 3500ppm. Is this compatible with the following elog?
http://nodus.ligo.caltech.edu:8080/40m/11111
In fact, I'm afraid that the loss number in the above elog 11111 was not correct by a factor of 10.
Then, if so, can we believe this high loss number? (Nominally we expect ~100ppm loss per round trip...)

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