On 7 Nov 2010, at 12:41CET, James Moritz wrote:
... It is assumed that ... the post-filter stages [of a receiver] only need to be linear enough not to significantly impair the wanted signal, and there has to be a trade-off with other inherently non-linear functions too, such as AGC.
In one of his articles in the RSGB Bulletin on building your own (valve-based) SSB gear, the late G2DAF empahsised that for best results the AF stages of a receiver must be designed as if they were part of a HiFi system.