40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log  Not logged in ELOG logo
Entry  Fri Aug 12 19:13:25 2016, Praful, Update, Electronics, Mic Self Noise 8x
    Reply  Fri Aug 12 21:26:28 2016, rana, Update, PEM, Mic Self Noise 
       Reply  Mon Aug 15 12:23:56 2016, Praful, Update, PEM, Mic Self Noise 9x
Message ID: 12405     Entry time: Fri Aug 12 19:13:25 2016     Reply to this: 12406
Author: Praful 
Type: Update 
Category: Electronics 
Subject: Mic Self Noise 

I used the Wiener filtering method described by Ignacio and Jessica (https://dcc.ligo.org/DocDB/0119/T1500195/002/SURF_Final.pdf and https://dcc.ligo.org/public/0119/T1500194/001/Final_Report.pdf) and got the following results:




The channel readout has a gain of 0.0005 and the ADC is 16-bit and operates are 20V. The channel also reads the data out in Pa. I therefore had to multiply the timeseries by 1/0.0005=2000 to get it in units of counts and then by (20 Volts)/(2^16 counts) to get back to the original signal in volts. The PSDs were generated after doing this calibration. I also squared, integrated, and square rooted the PSDs to get an RMS voltage for each microphone as a sanity check:

Mic 1: 0.00036 V

Mic 2: 0.00023 V

Mic 3: 0.00028 V

These values seem reasonable given that the timeseries look like this:




Attachment 4: mic1_wiener.pdf  389 kB  Uploaded Fri Aug 12 20:16:59 2016  | Hide | Hide all
Attachment 5: mic2_wiener.pdf  390 kB  Uploaded Fri Aug 12 20:17:23 2016  | Hide | Hide all
Attachment 6: mic3_wiener.pdf  385 kB  Uploaded Fri Aug 12 20:17:35 2016  | Hide | Hide all
Attachment 7: timeseries_elog.pdf  223 kB  Uploaded Fri Aug 12 22:35:00 2016  | Hide | Hide all
ELOG V3.1.3-