[digitalradio] Direct RTTY Generation
A back-to-basics question for once... Is there any modern RTTY datacomms software that gives a single wire digital output for driving an FSK transmitter? Looked in the MultiPSK and MMTTY setup menus and nothing. While I realise there may be little call for such a one-wire drive now (although my not-too-old IC746 will take a RTTY input signal) it does lend itself to simple QRP designs for the less experienced constructor. Andy www.g4jnt.com
[digitalradio] NUE PSK31 Modem
Does anyone have a valid web address for the NUE PSK31 Modem now. All the ones found on a Google search seem to be broken Andy www.g4jnt.com
[digitalradio] (unknown)
The term Spread Spectrum can apply to any mode that spreads its energy over more than the necessary bandwidth. If we assume the necessary bandwidth to be equal to the signalling rate than anything other than single carrier modes technically fall into this category. Even WSPR coul dbe considered spread spectrum! Its 6Hz bandwidth is wider than the 1.5 B/s rate. Within the WSJT suite, JT65 is more of a spread spectrum mode, and outside Joe's suite, MT63 with its 2.5kHz for a few tens of Bits / second is even more extreme. Andy www.g4jnt.com
[digitalradio] (unknown)
Strictly, CW is a three symbol code with source coding (variable length alphabet, like varicode) with soft decision coding, and mild FEC (operators interpretation of the code based on S/N) and some convolutional coding with soft decisions (matching characters received against patterns / words. Once you start using soft decision decoding, error correction and mult- bit-per-symbol waveforms, it becomes a bit difficult to really call anything a digital modulation at all. Especially when analogue processing is mostly performed digitally now, anyway Andy www.g4jnt.com
