Digital Delay

[patdunham]

Does any-one know why there is a slight delay between the programme broadcast in analog and the same program in digital? It seems about a sentence, or a sec or two, but also varies from chanel to chanel

[DorsetJay]

Not 100% sure, but would say that the delay is due to the converting to and from digital signals.

Sound is analogue so needs to be converted into a digital format for digital transmission. Speakers are also analogue (they work by varying voltages) so when the digital signal gets to your digital radio, it needs to be converted back into analogue. This converting to and from analogue and digital takes additional time.

Obviously traditional analogue transmission and radios do not suffer form these extra steps.

[patdunham]

I was relating to FreeView TV broadcasts, but the same probably applies. Thanks

[Mattk]

ive always assumed it was because one comes via a local transmitter and the other comes from outer space which is slightly further away !

[patdunham]

It is not space-related. Freeview via an aerial has the delay. The signal from a Sky satellite is transmitted at such a frequency and resistance in the atmosphere is small that it is only a fraction of a second to receive the signal at your dish.

[Famous5]

So which of the Greenwich Time Signal pips is correct, analog or digital and how will the delay be covered when analog finally disappears?