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US 2003/0151454 A1Published application
Adaptive speech filter
OwnerWilliam N. Bucheleinventor
Life of this patent
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Abstract
An adaptive speech filter (10) for conditioning speech signals to increase signal to noise ratio in a relatively noisy environment. The adaptive speech filter (10) has a preamp circuit (12), a high pass adaptive filter circuit (14), an output buffer circuit (16), a peak detector amplifier/filter circuit (18), a peak detector circuit (20) and a voltage regulator circuit (22), embodied in an application specific integrated circuit (24). The adaptive speech filter (10) is intended for input to telephones, radios, and the like.
Claims28
A filter circuit comprising:
- a filter circuit input terminal;
- a filter circuit output terminal;
- a high pass filter having a control input terminal, a signal input terminal, and a signal output terminal configured to provide a signal to said filter circuit output terminal;
- a peak detector having a control output connected to said control input terminal of the high pass filter;
- and
- a preamplifier configured to accept a signal from the filter circuit input terminal and further to provide a signal to said signal input terminal of the high pass filter and to a signal input terminal of the peak detector;
- wherein
- the corner frequency of the high pass filter is controlled by the control output of the peak detector;
- and
- the filter circuit is configured for receiving direct current power from said filter circuit signal output terminal.
7 more elements
A method for conditioning speech, comprising:
- a) providing a high pass filter;
- b) providing a peak detector for sensing of a signal level and providing a control signal in response thereto;
- c) controlling said high pass filter with said control signal such that a corner frequency of said high pass filter is dependent upon said signal level;
- and
- providing direct current power to said high pass filter, said peak detector, and the signal conditioning amplifier at an output of the signal conditioning amplifier.
2 more elements
A speech conditioning circuit for conditioning a signal, comprising:
- a variable filter circuit for filtering said signal to produce a conditioned signal, controlled by an amplitude detector circuit;
- and
- an output circuit receiving said conditioned signal from said variable filter circuit and providing an output signal to an output terminal, the speech conditioning circuit being constructed to accept a direct current input form said output terminal for powering the speech conditioning circuit.
A telephone input apparatus, comprising:
- a microphone preamplifier;
- a filter for removing low frequency signal content;
- a peak detector for controlling said filter;
- a peak detector amplifier for amplifying input to said peak detector;
- and
- a telephone input apparatus output terminal for providing signal output from the telephone input apparatus and also for providing direct current power input to the telephone input apparatus;
- wherein
- a signal from the preamplifier is provided to an input of the filter and said signal is also provided to an input of the peak detector, and further wherein
- a filtered signal is provided from the filter to the telephone input apparatus output terminal.
6 more elements
A filter circuit comprising:
- a filter circuit input terminal for receiving a filter circuit input signal;
- a filter circuit output terminal for providing a filter output signal;
- a high pass filter having a control input terminal, the high pass filter for processing a high pass filter input signal to produce said filter output signal;
- a peak detector having a control output connected to said control input terminal of the high pass filter;
- and
- a preamplifier configured to receive said filter circuit input signal and further to provide said high pass filter input signal to the high pass filter and to the peak detector;
- wherein
- the corner frequency of the high pass filter is controlled by the control output of the peak detector;
- the high pass filter, the peak detector and the preamplifier are embodied in an integrated circuit;
- and
- the gain of the preamplifier is adjustable through gain adjusting means external to said integrated circuit;
- whereby the preamplifier is configurable to adapt gain for a device connected to said filter circuit input terminal.
9 more elements
Dependencies are inferred from the claim text.