Although CMRR is an issue, it's not always the overriding factor.
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Noise is frequently introduced via a poor quality power supply, badly designed bias tee, ground loops, and poor screening of the feed line, and the amplifier CMRR performance is not going to significantly change the end result.
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I'd suggest that it's always best to check for some of the more obvious issues first, by looking at the spectrum with the amplifier powered, but with the input shorted, and no loop connected, and then fixing those problems, before you move on to try and resolve any additional contribution due to poor CMRR.
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Regards,
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Martin
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On Sun, Feb 2, 2025 at 05:49 AM, <biastee@...> wrote:
Two different paths for noise ingress, but one common parameter (CMRR) standing in their way?
