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From: | Tom Rondeau |
Subject: | Re: [Discuss-gnuradio] Bit shift sync error with DPSK |
Date: | Mon, 31 Dec 2012 14:20:07 -0500 |
I'm trying to get a simple PSK loopback working in GRC, File Source -> DPSK
Mod -> DPSK Demod -> Unpacked to Packed -> File Sink.
On Ubuntu 12.10 x64 (build-gnuradio a few days ago), the sink file winds up
with leading 7 bytes x00, 3 bytes plus one bit noise, four mangled bits, and
then my correct bitstream. But the odd bit causes the entire remainder of
the bitstream to be right-shifted by one. Throttling doesn't seem to have
any effect.
Interestingly enough, using MSWin7, I get 6 bytes x00, 2 bytes noise, 26
bytes mangle, and then a correctly aligned stream of bytes (other than a
mangled sequence from about bytes 100-107).
Am I missing something to provide symbol timing recovery?
The GRC file is at
https://docs.google.com/open?id=0B56aEJNJrwBAX2NhMHczdGhUejA
TIA,
Chris
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