J. Forster wrote:
Somebody mentioned TV and radio stations recently. (I think it was part
of the North discussion.)
What sort of frequency source is at the root of the local TV or radio
stations?
Is the sync timing for TV stations derived from the same source as the
carrier? Or are there two separate clocks to discuss? How about the
color-burst frequency?
NTSC is gone w/ analog TV. No color burst any more.
There are other forms of pilot-signals in the OFDM spectrum. That is
needed to keep the digital receiver frequency locked to the signal. Read
the specs of your favorite terrestrial digital network of choice.
What do radio/TV stations do for backups? If there was a hurricane or
earthquake that broke the main transmitter are they likely to switch to a
backup with a different timing source?
I'm not sure, but when satellite links go down, the picture freezes. That
implies a frame store which is likely bad news for timing.
That is what the MPEG-2/4 decode does. It stops updating it's play-out
frame-buffer. It's not a frame-store by necessity.
Cheers,
Magnus
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