I figured out the bandwidth issue at a.f. - it's due to low pass filtering inherent in the current dsp code. If you shift the center freq up from default 1.6Khz to 1.75Khz, you will indeed see 2.9Khz a.f. bandwidth at the -6dB points. You'll lose a bit of the low end response however.
73, Barry N1EU Barry N1EU wrote: > > Bill, I think the 2.9Khz bandwidth measurements for that filter were taken > at r.f. - for whatever reason, that bandwidth is not translating into a.f. > - I've seen a.f. measurements done on about 5 samples of the 2.7Khz filter > and they all run several hundred hertz narrower than the 2.9Khz figure. > > 73, > Barry N1EU > > > > Bill W4ZV wrote: >> >> >> >> Stewart G3RXQ wrote: >>> >>> >>> On USB the trace was substantially flat with the -3dB points at >>> 430Hz and 2.77KHz. Not too bad and could probably be improved by >>> moving the carrier offset frequency. >>> >>> >> >> One more point. The -3 dB bandwidth you are reporting is only 2.34 kHz >> on a filter that is typically 2.9 kHz at the -6 dB points (mine and the >> one measured by Elecraft below). That seems very strange also. >> > > -- View this message in context: http://www.nabble.com/K3-SSB----Is-the-5-pole-filter-good-enough-tp15664900p15670262.html Sent from the Elecraft mailing list archive at Nabble.com. _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
