Adaptive signal strength and/or ambient noise driven audio shaping system
First Claim
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1. An adaptive audio filter arrangement for a radio receiver having RF, IF, detector, and audio sections comprising:
- means, interposed between the detector and the audio sections, for providing a plurality of filter responses dependent upon a control signal applied thereto, including at least switchable filter means; and
control signal generating means, coupled to said means for providing a plurality of filter responses and the IF section, for providing at least one of a plurality of available control signals which are related to the signal to noise ratio of the receiver for effecting one of the plurality of frequency responses thereof.
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Abstract
An adaptive audio filter system is disclosed which comprises a filter means capable of producing a plurality of frequency response characteristics. A control signal generating means provides a control signal to the filter means to enable a particular frequency response. The control signal is based upon the signal to noise ratio.
157 Citations
20 Claims
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1. An adaptive audio filter arrangement for a radio receiver having RF, IF, detector, and audio sections comprising:
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means, interposed between the detector and the audio sections, for providing a plurality of filter responses dependent upon a control signal applied thereto, including at least switchable filter means; and control signal generating means, coupled to said means for providing a plurality of filter responses and the IF section, for providing at least one of a plurality of available control signals which are related to the signal to noise ratio of the receiver for effecting one of the plurality of frequency responses thereof. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An adaptive audio filter arrangement for a radio receiver having a front end, IF, and detector sections for providing an audio signal from the detector to a speaker, comprising:
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means for delaying the audio signal from the detector to an included switchable filter means, said switchable filter means for effecting a composite filter response from a plurality of narrow bandpass filters dependent upon a control signal applied thereto; and control signal generating means for determining the signal energy of frequency components in the audio signal from said detector and for generating the control signal which is coupled to said switchable filter means for effecting a composite filter response only for frequencies having signal energy above a certain threshold level. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. An adaptive audio filter arrangement for a radio receiver having a front end, IF, and detector sections for providing an audio signal from the detector to a speaker, comprising:
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a bucket brigade circuit for delaying the audio signal from the detector; a plurality of narrow bandpass filters, coupled to said bucket brigade circuit and switchably connected to said receiver for effecting a composite filter response dependent upon a control signal applied thereto; a sampling device, such as a set of conventional voltage limiters preceded by a filter, for determining the signal energy of frequency components in the audio signal by sampling and storing the audio signal from said detector; and a microprocessor, programmed for analyzing the signal energy of frequency components of the audio signal stored by said sampling device and generating a control signal therefrom, for effecting a composite filter response only for frequencies having signal energy above a certain threshold level.
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Specification