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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: 11579     Entry time: Fri Sep 4 20:42:14 2015     Reply to this: 11647
Author: gautam, rana 
Type: Update 
Category: CDS 
Subject: Checkout of the Wenzel dividers 

Some years ago I bought some dividers from Wenzel. For each arm, we have x256 and a x64 divider. Wired in series, that means we can divide each IR beat by 2^14.

The highest frequency we can read in our digital system is ~8100 Hz. This corresponds to an RF frequency of ~132 MHz which as much as the BBPD could go, but less than the fiber PDs.

Today we checked them out:

  1. They run on +15V power.
  2. For low RF frequencies (< 40 MHz) the signal level can be as low as -25 dBm.
  3. For frequencies up to 130 MHz, the signal should be > 0 dBm.
  4. In all cases, we get a square wave going from 0 ~ 2.5 V, so the limiter inside keeps the output amplitude roughly fixed at a high level.
  5. When the RF amplitude goes below the minimum, the output gets shaky and eventually drops to 0 V.

Since this seems promising, we're going to make a box on Monday to package both of these. There will one SMA input and output per channel.

Each channel will have a an amplifier since this need not be a low noise channel. The ZKL-1R5 seems like a good choice to me. G=40 dB and +15 dBm output.

Then Gautam will make a frequency counter module in the RCG which can do counting with square waves and not care about the wiggles in the waveform.

I think this ought to do the trick for our Coarse frequency discriminator. Then our Delay Box ought to be able to have a few MHz range and do all of the Fast ALS Carm that we need.

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