If I look at the audio response in Spectrogram while feeding in a noise source at the antenna the trace shows definite nulls when NR is switched in. In SSB at max width (2.7kHz) the number of nulls vary with the settings as follows: F1-# 9 F2-# 7 F3-# 4 F4-# 3
As # is increased from 1 to 4 at each F setting the depth of the nulls decreases and it's almost flat at #4. However RF gain and AGC slope settings drastically affect the depth of these nulls but at maximum the nulls are about -30db which would presumably affect the 'loudness' of a signal if it happened to fall in one of the holes? I don't have time at the moment to investigate further how the AGC settings affect the nulls but backing off the RF gain definitely flattens the response. According to Lyle back in 2007 the F parameter indicated the number of taps (?) in the adaptive filter and the second number the amount of signal 'bleed through' to reduce distortion effects. I'm not sure my limited knowledge of dsp and filters ties this in with what I see in Spectrogram..... Having said this I must admit I tend to use filtering in preference to NR even though I seem to be able to get NR to work pretty well. 73, Stewart Rolfe, GW0ETF Steve Ellington wrote: > > This is amazing....We have some who complain about NR increasing the audio > and some complaining about it reducing audio!........ > > -- View this message in context: http://n2.nabble.com/NB-NR-Noise-Blanker--Noise-reduction-tp2728863p2732318.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
