There is also something to be said about using IQ demodulation to get your sideband rejection ... Anyone who has an R2 or R2 Pro can attest to the fact it sounds better than a crystal filter based rig even with all analog circuitry ... so it's really a combination of digital filtering along with IQ sideband rejection
Based on studies of time-aligned speakers and crossovers I believe the effect of time-aligning the I and Q channels (Necessary to get sideband rejection, the better the rejection in Db, the better the time and phase alignment across the passband) simply makes the audio more pleasing to the ear and causes less ear fatigue, just as time-aligned studio monitors are more pleasing to the ear and cause less ear fatigue during long mixdown sessions JR -- In [email protected], "rhblumeng" <[EMAIL PROTECTED]> wrote: > > --- In [email protected], "i2phd" <i2phd@> wrote: > > Ciao Claudio, > > > > I do perfectly agree with you. The only problem is that if you > take > > two different persons, they react differently to a non linear phase > > response caused by the non constant group delay in the crystal > > filters. It's here where it starts the subjective part of the > > issue.... we can measure the group delay, but we can't tell anything > > about the effect that it will have on the listeners, as each of them > > will have a different perceived sensation of the quality of that > > audio.... what characterize an human being is his lack of > > predictability (and I would add, Thanks God...) > > > > 73 Alberto I2PHD > > Hi Alberto - > > There was something in Claudio's post that is more along the lines of > my earlier post: > ________________________ > "With Ciao Radio when it is used in AM with the AM demodulator that > implement the law of the envelope detector you clearly see the > distortion coming in the spectrum window of the demodulated signal > (even with dynamic signals). > When you use the coherent AM demodulator of Ciao Radio , you don't > have this distortion and the signal is clearer . > This is amplitude non linearity." > __________________________ > > We all assume that the better sound of the SDR is due to the dsp > filters, and the overwhelming portion may just be that. > > BUT, if one can "see" the improvement we all know is there in going > from an envelope type detector to a better type, could we not also > use this technology to "see" subtle differences in the > various "better" detectors (sync and others) and whether there is an > even cleaner sound to be had from improved detector algorithms? > > It can be easy when something makes a great deal of improvement, to > get caught up in celebration, and ignore other lesser, but perhaps > valuable opportunities. > > I am just trying to ascertain whether more experimentation with > detector algorithms could be fruitful... > > My best to you, Bob >
