Glenayre Electronics, Inc.

David W Glessner

Mark L Witsaman

Roger E Benz

Joel R Crowley-Dierks

Glenn S Fawcett

Edward J Anthony

John M Reyland, Jr

A two-way paging system (10) includes a plurality of personal paging units (16). The personal paging units (16) receive pages (18), and generate radio signals (28) in response to the pages. The system includes a transmitter (12) for generating the pages, and a receiver (14). The receiver includes first and second receiving circuitry (30) and (34). The first receiving circuitry receives radio signals from the personal paging units. The second receiving circuitry receives radio signals from a source other than the personal paging units. The receiver further includes a data processor (32) electronically linked with the first and second receiving circuitry in the receiver. The data processor determines the time period during which radio signals are received from the personal paging units by the first receiving circuitry, based on radio signals received from the other source by the second receiving circuitry. In a preferred embodiment, the second receiving circuitry receives radio signals from the transmitter.

System for maintaining receiver/transmitter synchronization with two-way

A clock synchronization system for synchronizing a number of paging stations (24) with a system controller (23). Each paging station has a clock that includes a counter (52) that indicates the current local time and which is sequentially incremented by a counter advance signal applied thereto. A voltage controlled oscillator (58) generates the clocking signal that controls the advancement of the counter. A CPU (50) in the system controller monitors the time indicated by the counter and compares it to timing information received from a system clock. The timing information includes a time mark and a time mark send time. The system clock transmits to each paging system the time mark. At a future time, the system clock transmits the time mark send time which is the precise time at which the time mark was transmitted. The paging stations each measure the time interval between the time at which the time mark arrived and the time at which the time mark was transmitted by the system clock period. By subtracting the time at which the time mark was transmitted by the system clock and the propagation time to each paging station, each paging station can determine and correct the error in its clock.

Method and apparatus for coordinating clocks in a simulcast network

A clock synchronization system for synchronizing the performance of a number of clocks (46) so that they run parallel with a reference clock is disclosed. Each clock of this synchronization system includes a counter (52) that indicates the current time and that is sequentially incremented by a counter advance signal applied thereto. A time counter controller (54) both initializes the counter and generates the clocking signal that controls the advancement of the counter. The time counter controller further monitors the time indicated by the counter and compares it to a reference-time signal received from a reference clock. Based on the comparison, the time counter controller selectively reinitializes the counter and adjusts the rate at which the clocking signal is applied to the counter so as to ensure that the counter advances at a rate equal to the rate at which the reference clock advances. In some versions of the invention, the comparison of the reference-time signal to the actual clock counter time is made at a maintenance operation point (58) remote from the clock. In these versions of the invention, the maintenance operation point reports the difference in the two times back to the time counter controller, which, in turn, makes the appropriate adjustments to the counter and to the clocking signal.

Apparatus for synchronizing a plurality of clocks in a simulcast network

A simulcast system for broadcasting the same signal for a number of spaced-apart broadcast sites is disclosed. The system (20) of this invention includes a hub (28) adapted to receive the signal to be simulcast and a number of stations (30) that actually broadcast the signal. The hub places the digital signal packets referred to as PDBs (36). As pan of the signal packetization process, the hub evaluates the rate at which the signals should be broadcast and assigns a start time at which the signals should be broadcast; this information is attached to the PDBs. After a PDB is created it is forwarded to the stations over a link channel. Each station includes a station controller (32) and a station transmitter (34). The station controller, upon receiving a PDB, forwards the signal therein to the transmitter at the start time indicated and at the appropriate broadcast rate. All of the stations transmitting the signals contained within a single PDB do so based on the start time and broadcast rate information contained in that PDB. Consequently, each station broadcasts the same signals at the same time and at the same rate so as to ensure their simultaneous transmission.

Digital simulcast transmission system

A simulcast system for broadcasting the same signal for a number of spaced-apart broadcast sites is disclosed. The system (20) of this invention includes a hub (28) adapted to receive the signal to be simulcast and a number of stations (30) that actually broadcast the signal. The hub places the digital signal packets referred to as PDBs (36). As part of the signal packetization process, the hub evaluates the rate at which the signals should be broadcast and assigns a start time at which the signals should be broadcast; this information is attached to the PDBs. After a PDB is created it is forwarded to the stations over a link channel. Each station includes a station controller (32) and a station transmitter (34). The station controller, upon receiving a PDB, forwards the signal therein to the transmitter at the start time indicated and at the appropriate broadcast rate. All of the stations transmitting the signals contained within a single PDB do so based on the start time and broadcast rate information contained in that PDB. Consequently, each station broadcasts the same signals at the same time and at the same rate so as to ensure their simultaneous transmission.

Growing community of inventors

Quincy, IL, United States of America

David W Glessner