Multiple channel automatic simulcast control system

An apparatus for effecting simulcast broadcasting of signals comprising:

• a. a source of information;
• b. a clock for providing a master timebase to the apparatus;
• c. a network control unit connected to the source of information to produce a signal containing digital identifying information and timing information derived from the clock for broadcast of the signal in a forward link system;
• d. a plurality of transmitters each connected to the network control unit to receive the signal from the network control unit and simulcast a radio broadcast containing the signal at a frequency controlled by the timing information, wherein the master timebase of the signal received from the network control unit is phase locked with a local timebase residing at each one of the plurality of transmitters;
• e. a network interface unit connected between each of the transmitters and the network control unit;
• f. a receiver located to receive the simulcast radio broadcasts;
• and
• g. a network monitor unit connected to the receiver and to the network control unit to supply information to the network control unit to control the radio simulcast broadcast, including control of the frequency of the simulcast broadcast to maintain frequency synchronization, wherein a timebase at the network monitoring unit is derived from phase locking a local clock at the network monitoring unit with the master timebase at the network control unit.

A method of synchronizing in a simulcast broadcasting system, comprising the steps of:

• providing a source of information to a network control unit;
• producing a signal at the network control unit containing data from the source of information and digital identifying information, providing a produced signal;
• clocking the produced signal with a high stability local clock reference at the network control unit providing a clocked link system signal;
• providing the clocked link system signal to a plurality of network interface units and transmitters each connected to the network control unit;
• phase locking the clocked link system signal with a local oscillator at the network interface units, producing a phase locked clock signal;
• monitoring and comparing the phase locked clock signal at a network monitoring unit with another local oscillator at the network monitoring unit;
• determining the discrepancy between the phase locked clock signal at the network interface unit with the local oscillator at the network monitoring unit;
• and
• sending an adjustment signal to the network control unit in response to the discrepancy found between the phase locked clock signal at one of the network interface units and the local oscillator at the network monitoring unit;
• forward synchronizing by the network control unit to the corresponding transmitter having the discrepancy in the network interface unit in response to the adjustment signal received at the network control unit.

A simulcast broadcasting system, comprising:

• a plurality of geographically dispersed radio transmitters providing simultaneous broadcasting of common modulation;
• a network controller unit coupled to the geographically dispersed radio transmitters for providing overall control of the simulcast broadcasting system via a link system;
• a network monitoring unit having an associated receiver for monitoring each of the plurality of radio transmitters;
• a plurality of network interface units forming part of the link system, where each one of the plurality of network interface units reside at each one of the corresponding plurality of geographically dispersed radio transmitters;
• a local timebase at the network controller unit, the network interface unit, and the network monitoring unit, wherein the network monitoring unit measures the relative synchronization between the timebase at the network interface units and the timebase at the network monitoring unit and provides an adjustment signal to the network controller unit,
• forward synchronizing means for synchronizing a given transmitter associated with a given network interface unit in response to the adjustment signal received at the network controller unit.

A method for synchronizing a broadcast in a simulcast broadcasting system having a plurality of remote transmitters, comprising the steps of:

• at a network controller unit:
• receiving a source of information from a plurality of inputs;
• clocking the source of information with a high stability clock reference to provide clocked information to the plurality of remote transmitters;
• sending adjustment commands during a maintenance cycle to the remote transmitters after one of a plurality of network monitoring units detects a phase difference between a timebase at the network monitoring unit and a timebase at one of the remote transmitters, wherein the timebase at the remote transmitters and the network monitoring units are each individually derived from the high stability clock reference at the network controller unit;
• at each of plurality of network monitoring units:
• monitoring and measuring synchronization between the timebase at one of the plurality of remote transmitters in a non-simulcast, non-interfering basis, wherein measurements are taken by assigned measurement time slots;
• and
• sending an adjustment signal to the network controller unit in response to the detection of the phase difference between the timebase at the network monitoring unit and the timebase at the transmitter being monitored, wherein the network controller unit sends the adjustment command to the transmitter being monitored in response to the adjustment signal from the network monitoring unit.

An apparatus for effecting simulcast broadcasting of data, comprising:

• a source of information;
• a network control unit, having a high-stability timebase, coupled to the source of information to produce a signal containing data and digital identifying information, the signal clocked from the high-stability timebase;
• and
• a plurality of transmitters, each coupled to the network control unit to receive the signal, and each having a modulation-generating timebase,
• each modulation-generating timebase phase locked to the high-stability timebase by way of synchronization information included in the signal, and
• each modulation-generating timebase adjusted by a corresponding correction value provided by the network control unit, thereby providing a highly accurate coincident modulation of the plurality of transmitters during a radio broadcast containing the signal.

A method for effecting simulcast broadcasting of data, comprising the steps of:

• providing a source of information for a network control unit;
• synchronizing the network control unit to a high stability timebase;
• generating a signal, at the network control unit, containing data and digital identifying information, the signal clocked by the high-stability timebase;
• providing to a plurality of transmitters the signal, the plurality of transmitters each having a modulation-generating timebase;
• phase locking, at the plurality of transmitters, each modulation-generating timebase to the high-stability timebase by way of synchronization information included in the signal;
• and
• adjusting each modulation-generating timebase by a corresponding correction value provided by the network control unit, thereby providing a highly accurate coincident modulation of the plurality of transmitters during a radio broadcast containing the signal.