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Operational amplifier - loop gain measurement

Question asked by maikhermanns on Feb 9, 2016
Hi all together,

I want to measure the loop gain of a low frequency (about 100kHz) inverting amplifier circuit with V=100 and 1k input impedance - to determine phase reserve / stability.
Already read AN5989-9799EN, but want to examine the infuence of some filters on the input and output of my amplifier, so the feedback loop is not totally known / modeled. (I already did some spice simualtions)

Are there any suggestions or white papers how to do the signal insertion. I found an old appnote ("LOOP GAIN MEASUREMENTS WITH THE HP 3577A NETWORK ANALYZER") - and look for some ideas - if that injection could be a goog idea - and which pitfalls will disturb my measurements.

We have here a bunch of VNAs - from an modern Fieldfox, an 8753ES down to an old 8751A with an direct accessible reference input.

hoping for advice 

with kind regards

Maik  

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