Eric Swartz -WA6HHQ, Elecraft wrote: > > If this is set well above what is really needed, the DSP may generate > some distortion on really strong signals. We usually recommend +4 dB max.
I wonder if distorting the audio is really what APF is about. With a narrow enough filter, the distortion products will only be based on the signal. Alternatively, and more worrying, it may be about defeating the ear's defences against load sounds, by making the spectrum too narrow, in which case there may be a risk of burning out the hair cells for the chosen frequency. More generally, the APF proponents seem to have the problem that they treat it almost as magic. If they could characterise what it does in terms of filtering, AF gain adjustment, distortion etc. it should be possible to simulate it in DSP, subject only to having enough processing power. In particular, peaking just seems to me to mean turning up the AF gain in parallel with reducing the bandwidth. If that is all that it is doing, and if the K3 has soft AF gain controls, a plugin box could issue both commands in parallel. PS the relevance of AGC here is whether or not it is applied pre- or post- the ultimate selectivity. From what the APF people say, it is normally applied pre-. -- David Woolley "we do not overly restrict the subject matter on the list, and we encourage postings on a wide range of amateur radio related topics" List Guidelines <http://www.elecraft.com/elecraft_list_guidelines.htm> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
