Hi Bill, I realized that just after pressing send. The 90Hz bandwidth (I call it acoustic bandwidth since it is encoded as a PCM audio signal) is occupied by a spectrally narrow tone at any given point in time so my concern is not valid. The concern would be valid for other modulation techniques that fully utilize the 90Hz at all times during transmission. Never mind...
Thanks and 73, Mike KK7ER -----Original Message----- From: Bill Somerville [mailto:g4...@classdesign.com] Sent: Friday, April 26, 2019 11:06 AM To: wsjt-devel@lists.sourceforge.net Subject: Re: [wsjt-devel] FT4 gain adjustment On 26/04/2019 18:51, Deisher, Michael wrote: > FT4 acoustic bandwidth is nearly twice that of FT8. Hi Mike, that is not correct. The FT4 signal is one-tone GFSK. At any point in time there is only one tone with constant amplitude. In this respect the difference between FT8 and FT4 is that FT8 uses 8 different frequencies to encode symbols and FT4 uses just 4 different frequencies to encode symbols. I am not sure how "acoustic bandwidth" is relevant, whatever that is. The baseband signal is used to modulate an RF carrier so the resulting signal is not acoustic. 73 Bill G4WJS. _______________________________________________ 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
