Synchronization of broadcast facilities via microwave tone

• US 6,349,215 B1
• Filed: 03/29/2000
• Issued: 02/19/2002
• Est. Priority Date: 05/21/1999
• Status: Expired due to Fees

• Current Assignee: Warren L. Braun
• Original Assignee: Warren L. Braun
• Inventors: Braun, Warren L.
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): Davis, Temica M.
• Application Number:
  US09/537,091
• Time in Patent Office: 692 Days
• Field of Search: 455/12.1, 455/13.1, 455/13.2, 455/502, 455/11.1, 455/503, 455/3.01, 455/3.02, 455/16, 455/17, 455/112, 375/356, 370/319, 370/324, 370/343, 370/350, 370/525, 370/526
• US Class Current: 455/502
• CPC Class Codes: H04B 7/18523 Satellite systems for providing broadcast service to terrestrial stations, i.e. broadcast satellite service arrangements specially adapted for satellite broadcast receiving H04H40/90; picture transmission via satellite H04N1/00103; television transmission via satellite H04N7/20

Abstract

Interference effects between television transmitters for amplitude modulated or digital video and operating on a common allocated channel or frequency is avoided while discrimination is improved by synchronizing carrier signals for a plurality of transmitters. Booster transmitters for correcting coverage anomalies can operate of the same channel or frequency rather than requiring a different channel or frequency presently required in translators; making all allocable channels available for diverse broadcast programming. Discrimination between transmitters operating on the same channel or frequency but with potentially differing programming can be achieved with directional antennas. Synchronization of carrier signals is achieved by frequency multiplication of a tone relayed over a microwave transmission channel by an integral power of two using one or more serially connected full-wave rectifier stages and tuned filters.

Claims

1. A method of synchronizing a plurality of broadcast transmitters, including steps of

relaying a synchronization tone to said plurality of transmitters by microwave transmission,

multiplying a frequency of said synchronization tone to obtain a desired carrier frequency at each of said plurality of transmitters, and

modulating said carrier frequency simultaneously at said plurality of broadcast transmitters with a modulation signal.

2. A method as recited in claim 1, including the further step of

deriving said modulation signal at one of said plurality of transmitters from a signal provided by another of said plurality of transmitters.

3. A method as recited in claim 2, wherein said modulation signal is derived from a signal transmitted to said one of said plurality of transmitters by a microwave link from said another of said plurality of transmitters.

4. A method as recited in claim 1, wherein said multiplying step includes the step of multiplying said synchronization tone by a factor of two in each of a plurality of stages.

5. A method as recited in claim 1, including the further step of

computing a frequency of said synchronization tone by dividing a desired carrier frequency by an integral power of two.

6. A method as recited in claim 1, including the further step of

discriminating reception between signals of respective broadcast transmitters having a common allocated channel or frequency with a directional antenna.

7. A broadcast transmitter system including

a plurality of transmitters having a common allocated channel or nominal carrier frequency, each respective transmitter of said plurality of transmitters including

means for receiving a tone having a frequency transmitted from a broadcast transmitter to each of said plurality of transmitters,

means for multiplying said frequency of said tone to derive a carrier frequency, and

means for modulating said carrier frequency with a broadcast signal.

8. A system as recited in claim 7, wherein said broadcast signal is derived from a signal received over a microwave link.

9. A system as recited in claim 7, wherein said means for multiplying said frequency of said tone includes a full-wave rectifier.

10. A system as recited in claim 9, wherein said means for multiplying said frequency of said tone further includes a tuned amplifier.

11. A system as recited in claim 7, wherein a common broadcast signal is used to modulate said carrier signal in each of said plurality of transmitters.

12. A system as recited in claim 7, wherein said tone is transmitted by microwave transmission.