RF SIMULCASTING SYSTEM WITH AUTOMATIC WIDE-RANGE DYNAMIC SYNCHRONIZATION

摘要

A new simulcast dynamic delay adjustment capability for a radio frequency (RF) simulcasting repeater system continually, dynamically adjusts the amount of delay applied to a T1 data stream to ensure common synchronization at multiple simulcast transmitter sites. A Global Positioning System (GPS) distributed time standard provides timing references at a control point and at each transmit site. The control point sends a version of its GPS timing reference signal to each transmit site over links also used to carry signals for transmission over-the-air. The transmit sites compare the arrival time of the land line-distributed reference signal with the output of a version of the same signal produced by a local GPS signal. The result of the comparison is used to adjust an amount of additional delay introduced to equalize delays for different transmission site links. This arrangement eliminates the need for resynchronization of the control point, allows for automatic, dynamic correction/compensation of path delay changes, and can correct delays over a wide range not known ahead of time (with the delay amount being independent of over-the-air timing reference signal frequencies - all without loss of service).