From: david brown <[EMAIL PROTECTED]> Subject: [time-nuts] Digital TV signals Date: Wed, 16 Apr 2008 09:25:21 -0700 Message-ID: <[EMAIL PROTECTED]>
> From a complete amateur, is there any useful timing info to be gained > from the newer format of digital tv transmission(Australia) to replace > that available from current analogue transmissions.? My recently > repaired TV derived frequency standard looks to be becoming obsolete! You are hanging of a DVB-T SFN system. SFN is a system variant where transmitters use a common time source (often GPS, but not always) to transmitt the signal at the same time. There is no real guarantee that any part of the signal is traceable, unless local authoratives or broadcasters themself put any such efforts in (which is possible). There is a small part of the signal which can be assumed traceable, even if the actual TV stream is not necessarilly traceable. Since you sit off an SFN network, the TV transmitter is traceable to the 10 MHz clock being fed into it, so the modulators pilot tones in the COFDM signal is indeed traceable back through the GPS receiver. If you download the ETSI documents for DVB-T I am sure you could engineer a receiver design, but frankly you could spend your time better on just doing a darn good GPS receiver instead, since you would be traceable back to GPS in most cases anyway, and not through the best of channels. Cheers, Magnus _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
