PCM decoding is working! I've managed to reverse engineer most of the protocol used by Futaba PCM1024 equipment and am now tackling the checksum and failsafe features. My code is able to accurately determine six of the nine channels fairly reliably, although some timing issues still remain.
Speaking of which, why can't they just use a regular serial protocol? There is a full MCU inside the PCM receivers, so it would be possible to include more useful features like start and stop bits, Manchester waves, sync points and such. Tracking an unknown 150 usecond bit clock over 30 ms is just asking for jitter and skew.
Full code is available from the CVS tree; a more details writeup will be posted on http://autopilot.sourceforge.net/ soon.