Patent ID: 8300668
Filing Date: 2012-10-30
Classification: H04H,H04J

Abstract:
1. A simulcast transmission system comprising: a source site including: a source generator configured to generate a timing packet, the timing packet containing a GPS timestamp generated at the source site; a source transmitter configured to transmit the timing packet and a content signal over a packet switched network to at least two transmitter sites; a plurality of transmitter sites configured to be coupled over the packet switched network to the source site, each transmitter site including: a receiver for receiving the timing packet and content signal from the packet switched network; a comparator configured to compare the GPS timestamp contained in the received timing packet to a GPS timestamp generated at a GPS receiver at the transmitter site to determine a differential ΔT representative of the difference between said timestamps; a delay processor, comprising a jitter buffer configured to receive said packets, that is responsive to an applied clock signal to provide an adjustable delay to said packets responsive to the comparator and configured to delay the received content signal by an amount related to ΔT, such that the content signals at said plurality of transmitter sites are substantially synchronized; wherein said delay processor includes a frequency locked loop for generating said clock signal, wherein said delay processor is responsive IP network delay determined from said comparison so that said clock signal; (i) when the determined network delay is static, is configured to drive said jitter buffer to clock said packets at the same rate said packets are received at said jitter buffer, (ii) when the determined network delay is increasing, is configured to drive said jitter buffer to clock said packets at a rate reduced with respect to the rate said packets are received at said jitter buffer, and (ii) when the determined network delay is decreasing, is configured to drive said jitter buffer to clock said packets at a rate increased with respect to the rate said packets are received at said jitter buffer.