Carrier phase synchronization system for improved amplitude modulation and television broadcast reception
First Claim
Patent Images
1. A method for synchronizing carrier phases of a group of co-channel amplitude-modulated broadcast signals, the method comprising:
- feeding a reference phase output from a multichannel receiver to a phase lock loop;
substantially eliminating audible and sub-audible beats between a local desired station'"'"'s carrier signal and one or more distant interfering stations'"'"' carriers; and
maintaining a predetermined phase relationship between a local desired station'"'"'s carrier signal and one or more distant interfering stations'"'"' carriers.
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Abstract
Systems and methods are described for carrier phase synchronization for improved AM and TV broadcast reception. A method includes synchronizing the phase of a carrier frequency of a broadcast signal with the phase of a remote reference frequency. An apparatus includes a receiver to detect the phase of a reference signal; a phase comparator coupled to the reference signal-phase receiver; a voltage controlled oscillator coupled to the phase comparator; and a phase-controlled radio frequency output coupled to the voltage controlled oscillator.
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Citations
23 Claims
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1. A method for synchronizing carrier phases of a group of co-channel amplitude-modulated broadcast signals, the method comprising:
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feeding a reference phase output from a multichannel receiver to a phase lock loop; substantially eliminating audible and sub-audible beats between a local desired station'"'"'s carrier signal and one or more distant interfering stations'"'"' carriers; and maintaining a predetermined phase relationship between a local desired station'"'"'s carrier signal and one or more distant interfering stations'"'"' carriers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. In a computer readable storage medium having stored therein data representing instructions executable by a computer system processor, the storage medium comprising instructions operative for:
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synchronizing the phase of a carrier frequency of a broadcast signal with the phase of a remote reference frequency; synchronizing the phase of another carrier frequency of another broadcast signal with the phase of the remote reference frequency, wherein both the carrier frequency and the another carrier frequency are of a same nominal frequency; modulating both the carrier of the broadcast signal and the another carrier of the another broadcast signal with a common audio program feed, wherein the modulation of the carrier of the broadcast signal and the modulation of the another carrier of the another broadcast signal are substantially equally delayed from a central network source; augmenting at least one of the broadcast signal or the another broadcast signal, with a repeater of the same nominal frequency; and monitoring a master skywave signal from the central network source. - View Dependent Claims (19, 20)
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21. A method comprising:
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detecting the phase of a first reference signal with a first multichannel receiver; outputting a first amplitude-modulated radio-frequency output with a first voltage-controlled oscillator; detecting the phase of a second reference signal with a second multichannel receiver; outputting a second amplitude-modulated radio-frequency output with a second voltage-controlled oscillator, providing a group of co-channel signals from the first amplitude-modulated radio-frequency output and the second amplitude-modulated radio-frequency output; and synchronizing carrier frequencies and phases of the group of co-channel signals to; (a) substantially eliminate audible and sub-audible beats between a local desired station'"'"'s carrier signal and one or more interfering stations'"'"' carriers; and (b) substantially reduce distortion effects in the signals as received in the coverage area overlapped by the two or more signals. - View Dependent Claims (22, 23)
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Specification