For my own curiosity I did some measurements of the latest APF. They agree with measurements of the first release with the exception that the filter peak is now zero beat instead of +10 Hz:
Zero beat = 7040.021 Flat passband = 021-020 (both 0.0 to -0.1 dB) -1 dB passband = 026-018 (-1.2 dB and -0.8 dB) -6 dB passband = 037-009 (-5.8 and -6.0 dB) Flat = 2 Hz BW (at zero beat) -1 dB = 8 Hz BW -6 dB = 28 Hz BW I didn't measure the -6 dB BW carefully on the first pass since I was more interested in the -1 dB BW, but this looks similar and agrees with Lyle's 30 Hz design goal. As mentioned previously, the -1 dB BW is important when trying to detect signals below the noise floor since the human ear can detect this difference in marginal conditions. I also checked the gain (APF vs not) which I didn't do before...+9.1 dB which is very close to Lyle's design goal of +9 dB. Nice job Elecraft! 73, Bill -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-APF-tp5735159p5735892.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ 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
