Joe, Thank you for the response.
I have read that article (and just reviewed it) and I stand corrected, a continuous-phase, frequency shift keying. The way ADX now generates the FSK signal (as many other similar generally low power digital transceivers) is to measure the audio coming out of WSJT-X and then adding the result to the base frequency in an SI5351. The SI5351 is sent a digital number which is the sum of the FSK offset and the base frequency. Would it be possible to sent the FSK frequency with greater resolution so that it approximated a continuous FSK signal? 73, Alan AG7XS > On Sep 19, 2022, at 10:27 AM, Joe Taylor via wsjt-devel > <wsjt-devel@lists.sourceforge.net> wrote: > > Hi Alan, > > On 9/19/2022 1:01 PM, Alan Altman AG7XS via wsjt-devel wrote: >> Greetings, >> Thank you for all the great work on creating and improving WSJT-X. >> You are probably aware of the ADX transceiver designed by WB2CBA. It is a >> simple open source digital HF rig designed for home brewing. We are working >> on replacing the Arduino with a RPi PICO. Due to differences in internal >> peripherals and timers, it is more complicated to measure the TX frequency >> in order to send it to the Si5351 DDS we use. >> In rethinking the problem, it occurred to me that WSJT-X must first generate >> a digital list or table of tones for each transmission before they are sent >> to the sound card and on to the rig as an analog signal. > > FT8 signals are not generated from a list of tones. Abrupt frequency changes > from one tone to the next would generate unwanted sidebands with amplitudes > far above those of a properly generated FT8 signal. For relevant details see > Figure 3 and the associated text in our QEX paper describing the FT4 and FT8 > protocols: > https://physics.princeton.edu//pulsar/k1jt/FT4_FT8_QEX.pdf > > -- 73, Joe, K1JT > >> What would greatly simplify the transition to PICO is if the TX audio >> frequencies could be sent out over USB in a directly useable format that >> could be directly added to the base frequency and on to the DDS. The best >> solution for ADX would be the final 0 to 3000 Hz tone frequency value be >> sent upon start of TX and each subsequent change in value or at a preset >> interval until the end of TX (stop value appended to release TX mode) or >> some other system if it is easier to implement on the WSJT-X side. Timing >> would be controlled by the WSJT-X. We have been using VOX or CAT control for >> PTT, but could update that to CAT only. >> In addition if USB CAT polling interval requests could be blocked during TX >> periods, that would be even great as it prevent dropouts and data conflicts >> if using a USB hub with audio dongle. >> 73, >> Alan >> AG7XS > > > _______________________________________________ > wsjt-devel mailing list > wsjt-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wsjt-devel _______________________________________________ wsjt-devel mailing list wsjt-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/wsjt-devel
