Yes, I ran the analysis on the circuit as shown, without the tuning control. If anyone wants to pore through the schematics and tell me the value of the control as well as where to put it, I'll be happy to run the analysis at the two ends of the range of the control. What I had wanted to do with my information was remove any mystery surrounding the topology of the circuit in the FT-1000. Now that we know what it is, it may help someone to try and duplicate it with hardware, software, or whatever. Al W6LX
--- On Sun, 8/16/09, Paul Christensen <w...@arrl.net> wrote: From: Paul Christensen <w...@arrl.net> Subject: Re: [Elecraft] APF vs 10 Hz DSP, why they don't sound the same To: elecraft@mailman.qth.net Date: Sunday, August 16, 2009, 4:39 PM > "The circuit surrounding op amp 3016-2 in the FT-1000 schematic is nothing > more than an active bandpass filter, center frequency of about 1025 Hz, Q > = 35, with a gain of about 10.5 dB." The APF filter is active on the Main Rx, CW mode only. However, Fc is not confined to 1025 Hz; with the front panel "APF" control, it's adjustable roughly over the range of the CW BFO offset when the filter switch is engaged. Paul, W9AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
