---+ Fitting Code for extracting the Carrier Frequencies from the Network Analysis

A network analysis is an algorithm that is run to measure the resonance frequencies of each bolometer carrier. It does not need to be done every cycle, and probably is not necessary to do every cooldown. The analyses should be run with the system in the following state:

In order to determine the optimum carrier frequencies such that the carriers fall nicely in the LC resonances, a network analysis is recorded. This can be fairly time consuming (3 hours for a 1000 channel system with x8 MUX). The algorithm MuxUI/scripts/mnetanal.py will perform this task. You need to edit the algorithm to tell it which readout channels to use, and the name of the output file. It will create two files - a 10kHz step baseline and a 500 Hz step datafile. Once the data is recorded, you need to analyse it with an IDL package, appended below.

The analyses should be run with the system in the following state:

• squids fully tuned and locked with the feedback resistors that will be used for data taking.
• fix all flux jumps first.
• the bolometers should be NORMAL, but the bolometer leads should NOT be normal - this means the UCSTAGE should be at about 700-900mK.

IDL Code for Fitting the Network Analysis Output to Find Optimal Carrier Frequency

After recording a network analysis, a package of IDL code (written by T. Lanting and M. Lueker with help from B. Benson and T. Crawford) is used to analyse the output. This code will produce a postscript file showing all of the results, and a text file listing the carrier frequencies. The IDL code (tested on Windows + Linux using SPT 3rd cooldown at the pole) is here:

1. unzip the IDL .tar.gz file and move your two datafiles into this directory.
2. 2007-02-13_NetworkAnalFitter.tar.gz: IDL Network Analysis Fitting code. A readme file inside gives brief explanation of how to use. This code works and is tested on both Windows and Linux versions of IDL.
3. The code used to create a hardware map (specific to a particular cooldown) is at config/create_wedge_file.

After running the code, it is a good idea to visually go over the results and compare them to the plots in the .ps file. Sometimes the fitter finds some funny solutions that are obviously not quite right.

-- MattDobbs - 13 Feb 2007

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This topic: AnalogFMux > WebHome > FMuxSoftwareGuide > SWNetworkAnalysisFitter Topic revision: r2 - 2007-03-01 - MattDobbs

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