Patent ID: 6741844
Filing Date: 2004-05-25
Classification: H03G,H04B

Abstract:
A receiver for audio enhancement operating within a radio communication system comprising:an antenna for receiving at least one radio frequency signal sent from the radio communication system; a preselector coupled to the antenna for filtering the received radio frequency signal, thereby generating a filtered radio frequency signal; an amplifier coupled to an output of the preselector for amplifying a desired portion of the filtered radio frequency signal, thereby generating an amplified radio frequency signal; a mixer coupled to an output of the amplifier and further coupled to a local oscillator for generating an intermediate frequency signal from the amplified radio frequency signal and a local oscillator signal; a filter coupled to the an output of the mixer for generating a filtered intermediate frequency signal by filtering the intermediate frequency signal; a signal strength measurement circuit coupled to the an output of the filter for measuring an amplitude level of the filtered intermediate frequency signal and generating a signal indicator level; a radio frequency signal detector coupled to an output of the amplifier for detecting an off channel signal strength and an on channel signal strength of the amplified radio frequency signal; and a processor, coupled to an output of the radio frequency signal detector and further coupled to the an output of the signal strength measurement circuit, wherein the processor is programmed to: receive the signal indicator level, generate an automatic gain control command based on the received signal indicator level, send the automatic gain control command to the amplifier to control a gain of the amplifier, receive the off channel signal strength, compare the off channel signal strength to a high threshold and a low threshold stored in the processor, categorize the off channel signal strength into a plurality of categories using the results of the comparison of the off channel signal strength to the high threshold and the low threshold, receive the on channel signal strength, compare the on channel signal strength to one or more pre-programmed values, categorize the on channel signal strength into the plurality of categories using the results of the comparison of the on channel signal strength to the one or more pre-programmed values, compare an on channel signal strength of at least one of the plurality of categories to an on channel signal strength level associated with the at least one category in response to the categorizing of the off channel signal strength, set a cutoff frequency for the filter using the results of the comparing of the on channel signal strength, generate a filter command including the cutoff frequency for the filter, and send the filter command to the filter.