At 02:52 PM 9/12/2005 +0100, Andy wrote:
John -
[..]
I'm surprised that you say the improvement with Africam was not that
significant. Surely, the biggest problem with any coherent scheme like PSK
is maintaining symbol timing and carrier lock. Certainly the timing can be
determined exactly, on a continuous basis, and most of the coherency issue
is resolvable too, so surely now that all the non-linear processing elements
of PSK reception have gone away shouldn't the net gain be potentially
massive ?
AFRICAM uses the GPS info for bit timing and framing, it does not attempt
to synthesize a coherent carrier. I keep hearing how difficult it is to
get some of those DDS-based BPSK generators out there to switch coherently,
at least without some modification. If anyone wants to transmit coherent
BPSK I'll look into the receive side this winter.
Bill
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