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 Wed Nov 23 17:48:16 2016, rana, koji, Update, IOO, How bad is the McWFS?
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 Sat Nov 26 19:16:28 2016, Koji, Update, IOO, IMC WFS Demod board measurement & analysis 
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Tue Nov 29 17:45:06 2016, Koji, Update, IOO, IMC WFS Demod board measurement & analysis
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Tue Nov 29 18:35:32 2016, rana, Update, IOO, IMC WFS Demod board measurement & analysis
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Fri Dec 2 18:02:37 2016, Koji, Update, IOO, IMC WFS Demod board measurement & analysis
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Sat Dec 3 13:27:35 2016, Koji, Update, IOO, IMC WFS Demod board measurement & analysis
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Tue Dec 6 13:37:02 2016, Koji, Update, IOO, IMC WFS Demod board measurement & analysis
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Tue Dec 6 16:47:40 2016, Koji, Update, IOO, IMC WFS whitening filter investigation
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Tue Dec 6 17:54:08 2016, Koji, Update, IOO, IMC WFS whitening filter investigation
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Tue Dec 6 22:41:49 2016, Koji, Update, IOO, IMC WFS whitening filter investigation
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Tue Dec 13 17:26:42 2016, Koji, Update, IOO, IMC WFS whitening filter investigation
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Thu Dec 15 03:46:19 2016, rana, Update, IOO, IMC WFS whitening filter investigation
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Message ID: 12668
Entry time: Tue Dec 6 13:37:02 2016
In reply to: 12662
Reply to this: 12669
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| Author: |
Koji |
| Type: |
Update |
| Category: |
IOO |
| Subject: |
IMC WFS Demod board measurement & analysis |
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I have implemented the modification to the demod boards (Attachment 1).
Now, I am looking at the noise in the whitening board. Attachment 2 shows the comparison of the error signal with the input of the whitening filter shorted and with the 50ohm terminator on the demodulator board. The message is that the whitening filter dominates the noise below 3Hz.
I am looking at the schematic of the whitening board D990196-B. It has an VGA AD602 at the input. I could not find the gain setting for this chip.
If the gain input is fixed at 0V, AD602 has the gain of 10dB. The later stages are the filters. I presume they have the thick film resistors.
Then they may also cause the noise. Not sure which is the case yet.
Also it seems that 0.7Hz noise is still present. We can say that this is coming from the demod board but not on the work bench but in the eurocard crate. |
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