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Entry  Wed Jan 25 15:41:29 2017, Lydia, Update, IMC, 29.5 MHz modulation depth measurement plan 
    Reply  Wed Jan 25 17:30:03 2017, Koji, Update, IMC, 29.5 MHz modulation depth measurement plan 
       Reply  Wed Jan 25 19:39:07 2017, gautam , Update, IMC, 29.5 MHz modulation depth measurement plan 
          Reply  Fri Jan 27 21:25:11 2017, Lydia, Update, IMC, 29.5 MHz modulation depth  
             Reply  Sat Jan 28 01:25:51 2017, gautam, Update, IMC, 29.5 MHz modulation depth  IMC_mod.pdfLockMCNew.png
                Reply  Mon Jan 30 19:07:48 2017, gautam, Update, IMC, RF AM stabilization box pulled out 
                   Reply  Tue Jan 31 01:07:20 2017, Lydia, Update, IMC, RF AM stabilization box pulled out AM_stablilizer_annotation.pdf
                      Reply  Tue Jan 31 13:46:34 2017, rana, Update, IMC, RF AM stabilization box pulled out 
                         Reply  Tue Jan 31 14:17:48 2017, gautam, Update, IMC, RF AM stabilization box pulled out 
                            Reply  Tue Jan 31 22:07:13 2017, gautam, Update, IMC, RF AM stabilization box revamp 
                            Reply  Tue Jan 31 22:28:39 2017, Lydia, Update, IMC, RF AM stabilization box pulled out AM_noise.pdf
                               Reply  Wed Feb 1 11:51:19 2017, Koji, Update, IMC, RF AM stabilization box pulled out 
                                  Reply  Wed Feb 1 16:45:56 2017, Lydia, Update, IMC, RF AM stabilizer box Modification Plan RF_AM_stabilizer_modification.pdf
                                     Reply  Wed Feb 1 20:49:34 2017, rana, Update, IMC, RF AM stabilizer box Modification Plan 
                                        Reply  Wed Feb 1 23:13:30 2017, Lydia, Update, IMC, RF AM stabilizer box Modification Plan 
                                           Reply  Sun Feb 5 21:56:50 2017, Lydia, Update, IMC, 29.5 MHz stabilizer box replacement 
                                              Reply  Tue Feb 7 12:01:10 2017, Lydia, Update, IMC, 29.5 MHz stabilizer box replacement RF_amp.pdf
                                                 Reply  Tue Feb 7 17:00:55 2017, Lydia, Update, IMC, 29.5 MHz stabilizer box replacement 
                                                    Reply  Fri Feb 10 02:14:10 2017, gautam, Update, IMC, 29.5 MHz stabilizer box replacement 
                                                       Reply  Fri Feb 10 11:41:43 2017, Lydia, Update, IMC, 29.5 MHz stabilizer box replacement 
                                                          Reply  Fri Feb 10 13:24:28 2017, rana, Update, IMC, 29.5 MHz stabilizer box replacement 
                                                             Reply  Fri Feb 10 18:21:21 2017, gautam, Update, IMC, IMC Demod board 
                                                                Reply  Fri Feb 10 19:32:15 2017, Koji, Update, IMC, IMC Demod board 
                                                                   Reply  Sun Feb 12 01:16:57 2017, gautam, Update, IMC, IMC length loop - summary of changes DemodBoardOrthogonality.pdfIMC_PDH.pdfTEK00001.PNGIMC_OLTF.pdfFSS_gain_comparison.pdf
                                                                      Reply  Mon Feb 13 11:55:14 2017, rana, Update, IMC, IMC length loop - summary of changes 
                                                                      Reply  Mon Feb 13 13:34:44 2017, gautam, Update, IMC, IMC length loop - bad SMA cable replaced noisy_PMC_REFL.png
                                                                         Reply  Mon Feb 13 19:44:55 2017, Lydia, Update, IMC, Front panel for 29.5 MHz amplifier box rfAmp.pdf
                                                                            Reply  Wed Mar 1 21:15:40 2017, Lydia, Update, IMC, Front panel for 29.5 MHz amplifier box RF_amp_(1).pdf
                                                                               Reply  Wed Mar 1 23:56:09 2017, gautam, Update, IMC, Front panel for 29.5 MHz amplifier box 
                                                                                  Reply  Thu Mar 2 20:32:18 2017, Lydia, Update, IMC, Front panel for 29.5 MHz amplifier box 
                                                                         Reply  Wed Feb 15 23:54:13 2017, gautam, Update, IMC, IMC saga continues... MCstrip.pngIMCweirdness.png
                                                                            Reply  Fri Feb 17 20:10:18 2017, gautam, Update, IMC, WFS servos turned back on 
                                                                               Reply  Sat Feb 18 14:09:06 2017, rana, Update, IMC, WFS servos turned back on 
                                                                                  Reply  Sat Feb 18 21:50:48 2017, gautam, Update, IMC, WFS servos turned back on WFS_error_noise.pdf
                                                                                     Reply  Sun Mar 5 12:41:23 2017, gautam, Update, IMC, WFS servo-steppin WFS_stepping.pngWFS_comparisons.pdfWFSdigitalAA.pdf
Message ID: 12784     Entry time: Wed Feb 1 16:45:56 2017     In reply to: 12783     Reply to this: 12785
Author: Lydia 
Type: Update 
Category: IMC 
Subject: RF AM stabilizer box Modification Plan 

Here's what I'm planning to do to the RF AM stabilizer box. I'm going to take out several of the components along the path to the EOM (comments in green), including the dead ERA-4 and ERA-5 amplifiers, the variable attenuator which is controlled by a switch that can't be accessed outside the box, and the feedback path from the daughter board servo. I'm arranging things so that the output of the HELA-10 does not exceed the maximum output power. 

I wasn't quite as sure what to do about the path to the ASC box (comments in blue). I talked with Gautam and he said this gets split equally between several singals, one of which goes to the LO of the demod board which expects -10 dBm and currently gets -12 dBm (can go up to -8 by turning switch). So maybe we don't actually want the signal to be anywhere near +27 dBm at the output. The plans for the box are here, it looks like +27 in will end up with +10 at each output, which is way more than what's currently coming out. But maybe this needs to be increased to match the other path? 

Also we haven't measured the actual response of the variable attenuator U4 for various switch positions; it's the same model as the one I'm removing from the EOM path and that one had slightly different behavior for different switch positions than what the spec sheet says. Same goes for the HELA-10 units along this path: what is their actual gain? So perhaps these should be measured and then a single attenuator should be chosen to get the right output signal level. Alternatively it could just be left alone, if it is at an OK level right now. Advice on what to do here would be appreciated.  

I'll work on the EOM path tonight and wait for feedback on the rest of it. 

EDIT: Gautam pointed out that there's some insertion loss from the components I'll be removing that hasn't been accounted for. Also the plans have been updated to reflect that I'm replacing AT5 with a 1dB attenuator (from 6 dB). 

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