El 18/11/15 a las 23:28, Phil Karn escribió:
I designed the DUV telemetry system on Fox-1, with an important suggestion (use 8b10b coding for spectral shaping) from Tony, AA2TX. It's important to remember the severe design compromises imposed by the requirement that the satellite itself be an analog FM repeater, confining the telemetry to modulating frequencies below 300 Hz.
These design compromises would have been unnecessary with a fully digital communications payload, like those on every non-amateur satellite launched in at least the past decade or two. I've made it clear that this is my last telemetry design for an analog spacecraft. It's past time for AMSAT to move into the all-digital era.
Dear Phil,
I'm wondering if it would be reasonable for future satellites to use an SDR transmitter, to allow to use an analog FM downlink and digital telemetry on two different frequencies (spaced about 20KHz apart or so). As others have said, analog FM is quite desirable because it allows for a very simple groundstation. Also, the current state of amateur digital voice is not so stable with all these competing standards that have closed implementations or use patented codecs.
73,
Dani M0HXM/EA4GPZ.