[ntp:questions] Can NTP sync within 1ms

[David Woolley]

On 27/04/14 17:28, Rob wrote:
> We are setting up a co-channel diversity network.  That means multiple
> FM transmitters that are transmitting the same signal on the same
> frequency on different sites, where the receive areas partly overlap.

This problem has already been solved using COFDM (aka DAB) and it is 
much more tolerant of fading that is inevitable with co-channel 
transmitters than your system.
>
> The listeners should enjoy a smooth reception while driving around.
> So of course there should be no time lag between the modulation signals
> of the different transmitters.  Experts in the field tell us we should
> be within 12us.

Your transmitters will have to be contained within a circle of 3.6km, 
reduced by the timing errors in the modulation at 0.3km/microsecond.