I know you will be happy that the generation and shaping you suggest is exactly what we do and what can be done either on the PC or the "Janus" board (new USB widget). The shaping derived by Frank for CW produces the most gorgeous scope patterns one can imagine for the elements. Predistortion can easily be added to the transmit IF filtering (as a convolution with the transmit filter). This has NOT been done. The transmit IQ/waveform distortion problem is a tough nut to crack without a sensor (which would essentially be another receiver).
73's Bob N4HY Guy Olinger, K2AV wrote: >Shaping and delaying the CW waveform in the PC or a slave device is >clearly the way to go. It is not a stretch of coding possibilities, >when using an SDR1000/amp combination, to (pre)shape the CW waveform >to cancel out whatever distortion is in the SDR1000/amp and transmit a >pristine CW signal completely devoid of clicks, while not sounding >excessively "soft", that fits well within a +/- 150 or 200 Hz >bandwidth. And, further, which has equipment state transitions, >including the SDR1000's, that are precisely timed to whatever >relays/switching in use, eliminating forever >state-change-during-transmit burned relay contacts. > >I've had a lifetime of direct interruption of continuous wave devices, >and have no interest in going back. Latency can be solved in >programming by technique and priority. Latency solved in hardware has >to be solved with a soldering iron, often repetitively. > >Guy. > > > > -- Robert W. McGwier, Ph.D. Center for Communications Research 805 Bunn Drive Princeton, NJ 08540 (609)-924-4600 (sig required by employer) _______________________________________________ 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
