AGC signal/noise question...
Hello.
I'm wondering about a thing...
When the AGC reduces the gain of an amplifier, composed by FETs (DG or SG)
or BJT, the SNR remains constant?
Or the performance of the amplifier may degrade/upgrade?
I'm researching about the matter and I just read that, in a BJT for instance,
emitter current is inversely proportional to the noise. So, if AGC reduces
the gain (so current), SNR degrade?
The question arises from a thing I just noted with a HF receiver... disabling
AGC reduces (slightly) the noise (at least in FM reception)...
Maybe just be a side effect, like noisy gain control signal...
Ciao,
AB
.... Andrea Baldoni, 2002: messaggio non protetto da copyright.
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