Method and apparatus for in-line detection of satellite signal lock
First Claim
1. A device for use in a satellite communication system having an antenna that receives a broadcast signal and an integrated receiver decoder coupled to the antenna the device comprising:
- a bypass circuit that is adapted to be coupled between the antenna and the integrated receiver decoder to convey a first portion of the broadcast signal from the antenna to the integrated receiver decoder;
a first filter circuit that is adapted to be coupled to the antenna to receive a second portion of the broadcast signal from the antenna and to pass a service signal to a first filter output;
a second filter circuit that is adapted to be coupled to the antenna to receive a third portion of the broadcast signal from the antenna and to pass a noise signal to a second filter output;
a difference circuit coupled to the first and second filter outputs that subtracts the second filter output from the first filter output to produce a difference signal; and
a comparison circuit that compares the difference signal to a first threshold associated with an incipient loss of lock on the broadcast signal.
1 Assignment
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Accused Products
Abstract
A method and system for detecting satellite signal lock in a satellite receiver system is disclosed. The system includes a first filter that isolates a noise frequency from the satellite signal, a second filter that isolates a service frequency from the satellite signal, circuits that derive a value indicative of the difference between a noise component and a service frequency component and output a difference signal level, a first comparator that determines whether the difference signal level is greater than a first threshold level, and a second comparator that determines whether the difference signal level is greater than a second threshold level. The method includes the steps of establishing a first threshold value between a satellite signal power level and the noise power level, combining a value indicative of a noise frequency signal component with a value indicative of a service frequency component to obtain a difference signal value, comparing the difference signal value with the first threshold value, and issuing a command if the difference signal value is below the first threshold value to inform the user of the loss of signal lock.
21 Citations
26 Claims
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1. A device for use in a satellite communication system having an antenna that receives a broadcast signal and an integrated receiver decoder coupled to the antenna the device comprising:
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a bypass circuit that is adapted to be coupled between the antenna and the integrated receiver decoder to convey a first portion of the broadcast signal from the antenna to the integrated receiver decoder; a first filter circuit that is adapted to be coupled to the antenna to receive a second portion of the broadcast signal from the antenna and to pass a service signal to a first filter output; a second filter circuit that is adapted to be coupled to the antenna to receive a third portion of the broadcast signal from the antenna and to pass a noise signal to a second filter output; a difference circuit coupled to the first and second filter outputs that subtracts the second filter output from the first filter output to produce a difference signal; and a comparison circuit that compares the difference signal to a first threshold associated with an incipient loss of lock on the broadcast signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system for detecting a satellite signal, the system comprising:
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a first filter having a passband center frequency between a first transponder center frequency of a first transponder band having a first polarization and a second transponder center frequency of a second transponder band having a second polarization and overlapping the first transponder band; a second filter having a passband center frequency associated with a non-service band; a difference block that generates a difference value based on an output of the first filter and an output of the second filter; and a comparison block that compares the difference value to a threshold value associated with a loss of lock on the satellite signal. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A system for detecting a satellite signal lock, the system comprising:
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a first filter having a passband center frequency substantially equal to a first transponder center frequency of a first transponder band; a second filter having a passband center frequency substantially equal to a second transponder center frequency of a second transponder band staggered wit respect to the first transponder band; a third filter having a passband center frequency associated with a non-service band; a difference block that generates a difference value based on outputs of the first, second and third filters; and a comparison block that compares the difference value to a threshold value associated with a loss of lock on a broadcast satellite signal. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A system for detecting a satellite signal, the system comprising:
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a first filter having a passband center frequency between a first transponder center frequency of a first transponder band and a second transponder center frequency of a second transponder band different from the first transponder band; a second filter having a passband center frequency spectrally separate from the first and second transponder bands; a difference generator that generates a difference value based on an output of the first filter and an output of the second filter; and a comparator that compares the difference value to a threshold value associated with a loss of lock on the satellite signal. - View Dependent Claims (22, 23, 24)
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25. A method of detecting a broadcast satellite signal, comprising:
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filtering a received broadcast satellite signal to generate a service signal having a center frequency between a first transponder center frequency of a first transponder band and a second transponder center frequency of a second transponder band that overlaps the first transponder band; filtering the received broadcast satellite signal using a second filter having a passband center frequency associated with a non-service band that is spectrally separate from the first and second transponder bands; subtracting an output of the second filter from an output of the first filter to generate a difference value; and comparing the difference value to a threshold value associated with a loss of lock on the broadcast satellite signal. - View Dependent Claims (26)
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Specification