I was thinking of RTTY, and the effect on the transmitted signal if the signal supplied to the (non-linear final) amp has any distortion at all, which is then made even worse in the amp.
Or, asked another way, what would be the distortion limit of the exciter in order to transmit a "clean" RTTY signal from a non-linear (think C or E class) power amp using the SDR-1000 as the exciter? Jerry W4UK At 19:29 11/17/2006, you wrote: >Jerry, > >If Jim is correct, and I would have to think about it for awhile, >the answer is, It depends. The PSK31 signal has frequency and phase >information in it, and a RTTY has frequency in it only. So a PSK31 >signal needs a linear amp to preserve the phase information, while a >RTTY signal which has only alternating single frequencies does not. > > 73, Chas W1CG > > >At 01:59 PM 11/17/2006, Jerry Flanders wrote: >>In the FSK world, there is no requirement to operate amplifiers >>linearly. Is this true in the SDR1000 world as far as straight AFSK >>is concerned? >> >>Probably so if it can be assured that NO distortion is generated >>prior to the amp(?) >> >>Jerry W4UK >> >>At 18:35 11/17/2006, Jim Lux wrote: >> >At 09:14 AM 11/17/2006, Charles Greene wrote: >> > >FireBrick, >> > > >> > >AFSK only. >> > > >> > >73, Chas >> > >> > >> >In the SDR1000 world, there is NO difference between AFSK and >> >FSK. The modulated waveform is created at baseband as an I/Q stream >> >and then mixed to the RF output frequency in a single step. >> > >> >This isn't a matter of feeding an audio tone into a SSB transmitter >> >with constant LO vs changing the actual LO frequency. In the >> >SDR1000, the LO frequency shifting is done in software. >> > >> > >> > >> > >> > >At 11:47 AM 11/17/2006, FireBrick wrote: >> > > >I can't seem to find whether the sdr operates FSK or AFSK. >> > > >I prefer FSK for contesting. >> > > > >> > > > >> > > >----------------------------------------------------- >> > > >Don't be a sexist, broads hate that. >> > > >----------------------------------------------------- >> > > > >> > > >Bill H. in Chicagoland _______________________________________________ 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 Homepage: http://www.flex-radio.com
