[Elecraft] Noise Reduction

[Kevin der Kinderen]

Maybe the additional noise in the stages between where the filter would be
in IF and where it is in AF? I know I'm thinking of multi-stage RF/IF/AF
superhets and that might be what is tripping me up when it comes to a
single conversion SDR capability. Maybe there is no difference? Or maybe
components that make up a filter in an IF stage are more effective (higher
Q) than in an audio stage?

73,
Kev K4VD

On Wed, Aug 23, 2017 at 7:58 PM, Fred Jensen <k6dgw at foothill.net> wrote:

> Doesn't appear to say very much.  Other than the BW difference [RF/IF BW
> might be more than ultimate AF BW], and provided that the demodulated audio
> is free of IMD and other obnoxious distortion, I don't see why NR at AF
> wouldn't be essentially the same as at IF.  Obvious differences in the
> mechanisms to do it, and I'm sure there are dozens of nits that will be
> picked over this, but if you can find the signal in the noise [or the noise
> obscuring the signal] at the IF frequency, I can't see any reason why you
> can't do it at AF just as well.
>
> 73,
>
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>
> On 8/23/2017 4:06 PM, Walter Underwood wrote:
>
>> Discussion appears to be here.
>>
>> https://uk.groups.yahoo.com/neo/groups/SNR_group/info?v=1&t=
>> directory&ch=web&pub=groups&sec=dir&slk=363  <
>> https://uk.groups.yahoo.com/neo/groups/SNR_group/info?v=1&t
>> =directory&ch=web&pub=groups&sec=dir&slk=363>
>>
>> wunder
>> K6WRU
>> Walter Underwood
>> CM87wj
>> http://observer.wunderwood.org/  (my blog)
>>
>
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