Bill, thanks a million, I have difficulty explaining what is in the brain cells, this helps a lot, simple circuit, and agree that running this through a simulator would give the answers. I know some would not like the feature, but one does not have to use it. Its the difference for me of making the contact or not, so a really big deal. For causal operators they may never use it. 73 Merv KH7C > > 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. > > The circuit in question is on page 54 of the FT1000 schematic below: > > <http://www.radioamateur.eu/schemi/FT1000_user.pdf>http://www.radioamateur.eu/schemi/FT1000_user.pdf > > The APF is around Q3016-2 (including Rs 3062, 3065, 3067 per the > "un-modification" sheet on N1EU's website below). The circuit > schematic above has *not* been modified to the (incorrect) values > shown in the Yaesu service bulletin. > > http://n1eu.com/Mods/apf.pdf > > The FT-1000's APF is generally regarded by many as the best APF ever > done. It should be possible to plug this into a circuit simulator > and generate a frequency response plot that Lyle can emulate in the > DSP. I have a feeling that this is a very narrow and high-Q response > that is on the verge of ringing, but it should be possible to > duplicate the circuit in the DSP. > > 73, Bill W4ZV > > > > ______________________________________________________________ > 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 > >
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