Re: [amsat-bb] BPSK demod needed

["laura halliday" <marsgal42@xxxxxxxxxxx>]

Jim White <jim@coloradosatellite.com> wrote:

>Folks,
>I'm looking for off the shelf solutions for the 38k4 BPSK
>receiver/demodulator need at the Air Force Academy ground station.
>The next satellite being built there will have an S band 38k4 BPSK down
>link.  We can down convert from whatever government S band frequency we end
>up on to UHF or VHF.  But we need to solve the problem of receiving that
>signal to base band, then demodulating the BPSK to make TTL or RS-232 level
>bits.  Since this will be a LEO bird with an S band down link Doppler will
>be an issue, so auto lock and frequency tracking will be a plus...

The closest I've seen to these requirements are the BPSK
radios (terrestrial packet and HRPT) published by S53MV in
UKW-Berichte/VHF Communications.

The terrestrial radios must deal with frequency uncertainty,
while the HRPT radio must handle LEO Doppler. One design used
a PLL demodulator, while the other used an I/Q baseband
demodulator. The HRPT radio uses a 36 MHz IF with a TV SAW
filter, which I think is kinda neat.

Laura Halliday VE7LDH     "Que les nuages soient notre
Grid: CN89mg               pied a terre..."
                                   - Hospital/Shafte
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