Digital squelch tail system and method for same
AssigneeMotorola, Inc.
InventorPatrick J. Doran
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Abstract
A digital squelch tail system (120, 114) selectively attenuates audio output corresponding to a digital signal (156). A bit error rate estimator (210) generates bit error rates (201) for an input digital signal (156). A digital filter (220) coupled to the bit error rate estimator (210) outputs an error variation rate (202) related to a rate of change of the bit error rate. Audio output derived, at least in part, from the digital signal (156), is selectively attenuated with an attenuation rate based on the output (202) of the digital filter (220).
Claims15
A digital squelch tail system for selectively attenuating audio output corresponding to a digital signal, comprising:
- a bit error rate estimator having an input coupled to the digital signal, and having an output representing a bit error rate for the digital signal;
- a digital filter having an input coupled to the output of the bit error rate estimator, the digital filter having an output based on a rate of change for the bit error rate of the digital signal;
- and
- an output device having an audio output derived, at least in part, from the digital signal, wherein the audio output is selectively attenuated with an attenuation rate based on the output of the digital filter.
A radio communication device having a digital squelch tail system for selectively attenuating audio output, comprising:
- a radio receiver responsive to a modulated signal to produce a received digital signal;
- an error rate estimator coupled to the received digital signal and having an error rate output;
- a digital high pass filter coupled to error rate output and having an error variation rate output based on a rate of change of the error rate output;
- an audio output device having an input based on the received digital signal and having an audio output;
- and
- an audio output controller coupled to the audio output device and coupled to the digital high pass filter, and being responsive to attenuate audio output based, at least in part, on the error variation rate output.
A method for selectively attenuating audio output corresponding to a digital signal, comprising the steps of:
- generating bit error rates for portions of the digital signal;
- filtering the bit error rates to determine an error variation rate based on rate of change of the bit error rates;
- generating audio output derived, at least in part, from the digital signal;
- and
- selectively attenuating the audio output with an attenuation rate based on the error variation rate.
Dependencies are inferred from the claim text.