The APF algorithm is unchanged. Lyle is going to verify. Wayne
---- http://www.elecraft.com On Nov 13, 2010, at 1:19 PM, "Bill VanAlstyne W5WVO" <[email protected]> wrote: > Joe wrote: > >> I did not make similar measurements with the original alpha >> test version but this version seems subjectively less tight >> than the original ... there is certainly less ringing with >> this one but signals did not seem to "pop" like they did on >> the earlier version when I tried it last night on 160/80/40. > > Joe, I agree with your subjective observation. No, the signals don't "pop" > as much -- but there is less ringing. This is a trade-off, of course, and > the precise balance of peak gain versus ringing is always going to be a > matter of personal preference. > > I like this less-ringy version better, I think. Haven't had time to play > with it a lot yet, but I will. I'm sure we will see many other opinions. So > far, I think the current version is very smooth and adequately "peaky". > > (Opinion subject to revision upon more extensive usage.) > > Bill W5WVO > > > -----Original Message----- > From: Joe Subich, W4TV > Sent: Saturday, November 13, 2010 20:35 > To: [email protected] > Subject: Re: [Elecraft] K3 APF > > > I made a similar set of measurements ... using the XG-2 and > the AFV/dBV capability ... > > I measure the peak at 1 Hz wide (e.g. -.1dB +/- 1 Hz) > the 1 dB points are 8 Hz wide > the 6 dB points are 31 Hz wide > the 20 dB points are 165 Hz wide > the 30 dB points are 345 Hz wide > gain is right at 9 dB. > > The measurements were made on 40 Meters with the XG-2 set to > 1 uV and the K3 attenuator activated yielding a -108 dBm test > signal. > > I did not make similar measurements with the original alpha > test version but this version seems subjectively less tight > than the original ... there is certainly less ringing with > this one but signals did not seem to "pop" like they did on > the earlier version when I tried it last night on 160/80/40. > > 73, > > ... Joe, W4TV > > > On 11/13/2010 1:24 PM, Bill W4ZV wrote: >> >> 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 >> >> > ______________________________________________________________ > 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 > > > ______________________________________________________________ > 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 ______________________________________________________________ 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
