40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  ATF eLog  Not logged in ELOG logo
Message ID: 2385     Entry time: Fri Aug 9 21:10:48 2019
Author: Shalika Singh 
Type: Noise Budget 
Category: 2micronLasers 
Subject: Noise Analysis of Circuit using SR785 Spectrum Analyser and Zero Simulation 

Input Referred noise is calculated for the circuit that is to be used for characterization of photodiodes. For the biasing 12V was used from SR560 as it provides cleaner voltage as compared to other voltage supplies. 

 

Attachment 1: The Circuit Diagram TIA

>>  the TIA with a gain of 5.1k

Attachment 2: Input Referred noise of TIA 

The input-referred current noise across the TIA was measured using SR785 and was compared against the graph obtained from ZERO simulation.

Attachment 3: Differential Circuit

>> gain of 100

Attachment 4: Input Referred noise of Differential Circuit

The input-referred voltage noise measured using SR785 and was compared against the graph obtained from ZERO simulation. 

Attachment 5: Whitening Filter Circuit

>> gain of 10

Attachment 6: Input Referred noise of Whitening Filter Circuit

The input-referred voltage noise was measured using SR785 and was compared against the graph obtained from ZERO simulation.

Some points that were observed: 

*** I am observing deviation from simulated results at higher frequencies. Presently, I am unable to understand the cause of this deviation. 

*** At low frequencies deviation from simulated results is perhaps caused due to 60Hz harmonics and 1/f noise.

Attachment 1: TIA.png  18 kB  Uploaded Fri Aug 9 22:15:57 2019  | Hide | Hide all
TIA.png
Attachment 2: Noise_across_TIA.pdf  87 kB  Uploaded Fri Aug 9 22:16:15 2019  | Hide | Hide all
Noise_across_TIA.pdf
Attachment 3: Differential_Circuit.png  25 kB  Uploaded Fri Aug 9 22:16:40 2019  | Hide | Hide all
Differential_Circuit.png
Attachment 4: Noise_across_Differential_Circuit.pdf  88 kB  Uploaded Fri Aug 9 22:17:04 2019  | Hide | Hide all
Noise_across_Differential_Circuit.pdf
Attachment 5: Whitening_Filter.png  27 kB  Uploaded Fri Aug 9 22:17:23 2019  | Hide | Hide all
Whitening_Filter.png
Attachment 6: Noise_across_Whitening_Filter.pdf  88 kB  Uploaded Fri Aug 9 22:24:57 2019  | Hide | Hide all
Noise_across_Whitening_Filter.pdf
ELOG V3.1.3-