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Re: Converter gain and noise..



At 09:44 AM 4/27/01 , you wrote:

>Wayne replies:
>
>An extremely high noise level effectively widens your IF bandwidth, allowing more noise and interference to get through relative to the desired signal.  For best signal-to-noise ratio, the noise level should be very low so that the desired signal is at an amplitude where the IF filter has its narrowest bandwidth.  Perhaps this is less of a problem with radios that use brick-wall IF DSP filtering.  But surely even those radios have crystal or ceramic filters in the first IF.


But wouldn't the receiver's AGC take care of this?  If the signal
is S9+20, isn't the AGC is reducing its amplitude a lot, and the IF
is actually seeing roughly the same signal level it would on a S1 signal?

Doug
NA1DB

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