Digital squelch circuit
AssigneeMotorola, Inc.
InventorJohn D. Wetters
Life of this patent
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Abstract
A digital squelch system (100) includes a timing signal generator (102) for generating a reference window. An edge detector (106) detects edges in the input signal during this reference window. An accumulator (110) accumulates the number of coherencies. An overflow detector (112) coupled to the accumulator (110) detects overflow conditions therein. A latch coupled to the overflow detector (112) squelches and unsquelches the radio (200) when the overflow or underflow conditions have been detected, respectively.
Claims12
A digital squelch system, comprising:
- a timing signal generator for generating a reference window;
- an edge detector for detecting edges of a received signal that occur in the reference window;
- an accumulator for accumulating the number of detected edges (coherencies);
- means for selecting a period of integration in accumulating coherencies in order to determine tight or lose squelch:
- an overflow detector responsive to the accumulator in order to detect an overflow condition in the accumulator;
- and
- a latch coupled to the overflow detector to unsquelch the audio.
A method for unsquelching audio in a communication device, comprising:
- receiving a sample of a signal:
- generating a reference window:
- counting occurrence of edges in the sample signal in the reference window:
- detecting when the number of edges is alcove a desired limit:
- unsquelching the communication device in response to the overflow;
- and
- selecting the period of integration for summing coherencies in order to determine tight or lose squelch states.
A communication device, comprising:
- A digital squelch system, comprising:
- a timing signal generator for generating a reference window;
- an edge detector for detecting edges of a received signal that occur in the reference window;
- an accumulator for accumulating the number of detected edges (coherencies);
- means for selecting a period of integration in accumulating coherencies in order to determine tight or lose squelch:
- an overflow detector responsive to the accumulator in order to detect an overflow condition in the accumulator;
- and
- a latch coupled to the overflow detector to unsquelch the audio.
Dependencies are inferred from the claim text.