Technique for measuring channel delay

Claim 1

In a simulcast system having a prime transmitter site coupled to a remote transmitter site via a channel, the channel having a delay, the prime transmitter site having a prime clock for providing a first value ("T1") based on the current time at the prime transmitter site, the remote transmitter site having a remote clock for providing a second value ("T2") based on the current time at the remote transmitter site, the prime clock and the remote clock being synchronized with a common timing signal so that T2 equals T1, the simulcast system arranged for determining the worst-case delay in accordance with a predetermined method, the method comprising the steps of: at the prime transmitter site: (a) determining T1; (b) simultaneous with step (a), sending a first message to the remote transmitter site; (c) saving T1; at the remote transmitter site: (d) receiving the first message; (e) simultaneous with step (d), determining T2; (f) sending a second message to the prime transmitter site, the second message including T2; at the prime transmitter site: (g) receiving the second message; (h) decoding the second message to determine T2; (i) determining the delay based on the difference between T2 and T1; (j) repeating steps (a) through (i) z times, thereby determining delay 1 , . . . , delay z ; (k) determining the worst-case delay for the channel based on the maximum delay of the group of delays consisting of delay 1 , . . . , delay z ; (l) waiting a predetermined time, and then repeating steps (a) through (k); (m) after step (l), then repeating steps (a) through (l) for a predetermined number (w) of times, thus determining the worst-case delay for the 1st trial, the worst-case delay for the 2nd trial, . . . , the worst-case delay for the (w-1)th trial, and the worst-case delay for the wth trial; where z is a predetermined number greater than 1, the predetermined number z being selected to determine the worst-case delay.