A question for the tech-literati

[djonn]

As I periodically have occasion to note when the blogosphere waxes ecstatic over some cable/satellite TV series or other, I am among the technologically backward retro folk whose TV signal comes over the air.  At present, I have one TV in the living room (analog plus converter box plus antenna) and a digital USB TV tuner plugged into my computer in the computer-lair (with an antenna attached to that tuner).  The latter allows my computer to function as a DVR (with a fair amount of room, as I got a 1TB external hard drive for Christmas this past year).

But I've noticed an odd phenomenon on those occasions when I have both the TV and the computer-TV on.

It's this: the signals on the two devices are out of sync by a second or two -- just about the length of a full spoken word.  Which creates a really odd echo effect if I happen to have both devices tuned to the same channel, since the apartment isn't that big.

Which doesn't make sense to me.  We're talking about the same TV channel, broadcast from the same tower, beaming into the same apartment, being picked up by two comparable antennas, displaying on two essentially similar screens.  The only explanation that seems even faintly plausible would be that the USB tuner might process the digital signal just a hair faster than the converter box -- but the thing is, I recall the exact same thing occurring before I'd bought the USB tuner, and instead had two analog TVs with two similar converter boxes.

So, O tech-literati, why should there be a time-lapse between the two signals?  Or am I merely losing the remnants of my mind?

Comments

[martianmooncrab.livejournal.com]

when dealing with TDM (time division multiplexing) you will always have a slight lag in signal. Each electronic device (in series) will attenuate the signal.

In simple terms, each electronic beastie takes a small nibble out of it, thus slowing it down.

[twilight2000.livejournal.com]

Not the useful answer you were hoping for (hope that's further downstream), but I'm guessing it's not unlike trying to listen to the radio and the Net Streamed version of the same station - there's a delay on the net streamed version - tho there it seems to be on purpose, so I don't know how related the two things are...

also - you should be watching Good Guys - it's hysterical (esp. to old West Wing folks ;>)

[alpha-strike.livejournal.com]

One device is always ahead of the other? I'd think that is processor speed, available memory, and the rate each device can re-broadcast in analog. If it's random, I vote for alien interference. If either television starts giving you commands, run.