A couple of observations... 1. ) I think a simple notch filter that is outside of the filter pass band, or its immediate skirts, is NOT going to effect anything that you hear within the filter pass band. Any transmitter splatter or intermod products that occurs before the ADC can not be removed by an outside of the passband notch filter after the ADC. There may be some smart processing that would be beneficial. 2) A manual notch filter ( or multiple filters ) inside of the passband could be useful. This filter would need to stay RF frequency locked as the receiver is tuned (i.e. not locked to the post detection audio frequency). 3) Notch filters (both manual and automatic ) need to be before the AGC loop such that the receiver gains is not suppressed by the amplitude of the notched signal. 4) With the full dynamic range of signal available from a SDR through VAC to external programs, the DSP in external programs can be nearly as good at the DSP in the SDR ( either by existing design or new improvements ) Think of the external special purpose programs as a second IF signal processor.
AL, K0VM _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ FlexRadio Homepage: http://www.flex-radio.com/
