Automatic synchronization system

• US 4,718,109 A
• Filed: 03/06/1986
• Issued: 01/05/1988
• Est. Priority Date: 03/06/1986
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Breeden, Robert L., Braun, William V.
• Primary Examiner(s): NG, JIN FAY
• Application Number:
  US06/815,473
• Time in Patent Office: 670 Days
• Field of Search: 455/18, 455/51, 455/56, 455/33, 340/825.44, 340/825.5, 370/108, 370/103, 375/107
• US Class Current: 455/503
• CPC Class Codes: H04H 20/67 Common-wave systems, i.e. using separate transmitters operating on substantially the same frequency

Abstract

An improved synchronization system for use with simulcast transmission systems is described. The invention provides a method and means for keeping the information signals for adjacent transmitters in the system in synchronization. This invention utilizes a centrally located master transmitter and control unit and a plurality of secondary transmitters disposed in an annular fashion around the master transmitter. In operation, the innermost annular band is synchronized to the master transmitter, while the remainder of the system is disabled. The next adjacent annular band is then synchronized to the innermost annular ring. The process is repeated until every annular band in the system is synchronized.

Claims

1. An improved automatic synchronization system for use with simulcast transmission systems and providing a means for keeping the information signals for all simulcast transmitters substantially in phase, said system comprising:

(a) primary base station means including a transmitter means;

(b) a plurality of secondary base station means disposed in a substantially annular fashion comprised of a plurality of annular bands including an innermost annular band surrounding said primary base station means; and

(c) terminal and controller means coupled to said primary and secondary base station means for generating sync-page signals and selectively activating and deactivating base station synchronization circuitry for synchronizing the plurality of base station means annular bands, wherein the innermost annular band is synchronized to said primary base station, and a remaining annular band is serially synchronized to an adjacent inner annular band.

2. The improved automatic synchronization system as recited in claim 1 wherein said primary base station means includes a transmitter for transmitting information, voice and synchronization information.

3. The improved automatic synchronization system as recited in claim 1 wherein said primary base station means includes an ID decoder for selectively activating the transmitter of said primary base station means.

4. The improved automatic synchronization system as recited in claim 1 wherein said primary base station means is coupled to said terminal and controller means via a wireline interface.

5. The improved automatic synchronization system as recited in claim 1 wherein said secondary base station means are coupled to said terminal and controller means via a wireline interface.

6. The improved automatic synchronization system as recited in claim 5 wherein said secondary base station means include monitor receiver means for receiving signals on the transmitter frequency of an adjacent inner annular band, and on the primary base station transmitter frequency in the case of the innermost annular band.

7. The improved automatic synchronization system as recited in claim 6 wherein said secondary base station means includes phase comparator means for comparing the relative phase of signals received over said wireline interface means and by said monitor receiver means.

8. The improved automatic synchronization system as recited in claim 7 wherein said secondary base station means include an adjustable delay network coupled to said phase comparator means for delaying the information or voice signal received over said wireline interface means to generate a delayed information or voice signal which is in-phase with the signal received by said monitor receiver means.

9. The improved automatic synchronization system as recited in claim 8 wherein said secondary base station means includes transmitter means for transmitting said delayed voice or information signal.

10. An improved automatic synchronization system for use with simulcast transmission systems and providing a means for keeping the information signals for adjacent simulcast transmitters substantially in phase, said system comprising:

(a) a primary base station means having decoder means for detecting the presence of an identification code, transmitter means for transmitting paging information, and means for selectively activating said transmitting means in response to detecting said identification code;

(b) a plurality of secondary base station means disposed in an annular fashion comprised of a plurality of substantially annular bands including an innermost annular band surrounding said primary base station means, said secondary base station means having a monitor receiver means, a modem means, individual decoder means for detecting the presence of a unique identification code, first and second sync-page detector means for generating an output pulse upon detecting the presence of a sync-page signal, sync-comparator means coupled to said first and second sync-page detectors for comparing the relative phase of said generated output pulses and generating a phase correction signal, adjustable delay means having an input coupled to said phase correction signal for producing a delay compensated signal, and further including transmitting means for transmitting said delay compensated signal; and

(c) terminal and controller means coupled to said primary and secondary base station means for generating sync-page signals and generating identification codes to selectively activate base station synchronization circuitry for synchronizing the plurality of base station means annular bands, wherein the innermost annular band is synchronized to said primary base station, and a remaining annular band is serially synchronized to an adjacent inner annular band.

11. An improved automatic synchronization system for use with simulcast transmission systems and providing a means for keeping the information signals for adjacent simulcast transmitters substantially in phase, said system comprising:

(a) primary base station means having wireline interface means, decoder means for detecting the presence of an identification code received at said wireline input means, transmitter means for transmitting paging information received over said wireline interface means, and means for selectively activating said transmitting means in response to detecting said identification code;

(b) a plurality of secondary base station means disposed in an annular fashion comprised of a plurality of substantially annular bands including an innermost annular band surrounding said primary base station means, said secondary base station means having a monitor receiver means for receiving RF signals from the adjacent inner annular base station means, and further including wireline interface means including a modem means, individual decoder means for detecting the presence of a unique identification code received over said wireline interface means, first and said sync-page detector means coupled to said monitor receiver means and said wireline input means respectively, for generating an output pulse upon detecting the presence of a sync-page signal, sync-comparator means coupled to said first and second sync-page detectors for comparing the relative phase of said generated output pulses and generating a phase correction signal, adjustable delay means coupled to said wireline input means, having an input coupled to said phase correction signal for producing a delay compensated signal, and further including transmitting means for transmitting said delay compensated signal; and

(c) terminal and controller means coupled to said primary and secondary base station means via the respective wireline interface means for generating sync-page signals and generating identification codes to selectively activate base station synchronization circuitry for synchronizing the plurality of base station means annular bands, wherein the innermost annular band is synchronized to said primary base station, and a remaining annular band is serially synchronized to the adjacent inner annular band.

12. A method of synchronizing information signals in a simulcast transmission system having a central control unit, a primary base station and a plurality of secondary base stations disposed in a plurality of substantially annular bands surrounding the primary base station, wherein said primary and secondary base stations include transmitters and synchronization circuitry and ID decoders for selectively activating base station transmitters or synchronizing circuitry, said method comprising the steps of:

(a) enabling the primary base station transmitter and the synchronization circuitry of the first annular band immediately adjacent to said primary base station, and synchronizing the base stations of said first annular band to the signal received from said primary base station;

(b) enabling the transmitters of the first annular band and the synchronization circuitry of the second annular band immediately adjacent to said first annular band, and synchronizing the base stations of said second annular band to the signal received from the transmitters of said first annular band; and

(c) enabling the transmitters of a previously synchronized inner annular band and the synchronization circuitry of an adjacent outer annular band, and synchronizing the base stations of said adjacent outer annular band to the signal received from the transmitters of said synchronized inner annular band until every base station in the system has been synchronized.