Periodic signal enhancement system
First Claim
1. A signal enhancement system comprising:
- a processor;
a signal input;
partitioned delay logic coupled to the signal input;
a partitioned adaptive filter coupled to the partitioned delay logic and comprising multiple adaptive filter outputs;
gain logic coupled to the adaptive filter outputs, where the gain logic is configured to receive an adaptive filter output signal from at least one of the adaptive filter outputs and generate a gain-weighted adaptive filter output signal from the adaptive filter output signal; and
signal reinforcement logic comprising an enhanced signal output, and where the processor is configured to execute the signal reinforcement logic to add the gain-weighted adaptive filter output signal to an input signal received on the signal input to increase a first periodic signal component in the input signal that is at least partially in-phase with a second periodic signal component in the gain-weighted adaptive filter output signal.
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Abstract
A signal enhancement system improves the understandability of speech or other audio signals. The system reinforces selected parts of the signal, may attenuate selected parts of the signal, and may increase SNR. The system includes delay logic, a partitioned adaptive filter, and signal reinforcement logic. The partitioned adaptive filter may track and enhance the fundamental frequency and harmonics in the input signal. The partitioned filter output signals may approximately reproduce the input signal, delayed by an integer multiple of the period of the fundamental frequency of the input signal. The reinforcement logic combines the input signal and the filtered signals to produce an enhanced output signal.
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Citations
50 Claims
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1. A signal enhancement system comprising:
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a processor; a signal input; partitioned delay logic coupled to the signal input; a partitioned adaptive filter coupled to the partitioned delay logic and comprising multiple adaptive filter outputs; gain logic coupled to the adaptive filter outputs, where the gain logic is configured to receive an adaptive filter output signal from at least one of the adaptive filter outputs and generate a gain-weighted adaptive filter output signal from the adaptive filter output signal; and signal reinforcement logic comprising an enhanced signal output, and where the processor is configured to execute the signal reinforcement logic to add the gain-weighted adaptive filter output signal to an input signal received on the signal input to increase a first periodic signal component in the input signal that is at least partially in-phase with a second periodic signal component in the gain-weighted adaptive filter output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for signal enhancement comprising:
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receiving an input signal; delaying the input signal by multiple delays; processing the multiply delayed input signal in a partitioned adaptive filter comprising multiple adaptive filter outputs; biasing an adaptive filter output signal received from at least one of the adaptive filter outputs to generate a gain-weighted adaptive filter output signal from the adaptive filter output signal; generating a summed adaptive filter output signal after biasing, where the summed adaptive filter output signal comprises a sum of the gain-weighted adaptive filter output signal and at least one other adaptive filter output signal; and reinforcing periodic signal content in the input signal with the summed adaptive filter output signal by adding the summed adaptive filter output signal to the input signal to increase a first periodic signal component in the input signal that is at least partially in-phase with a second periodic signal component in the summed adaptive filter output signal, where the act of reinforcing is performed by a processor executing signal reinforcement logic. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A product comprising:
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a machine readable storage medium; and machine readable instructions encoded on the medium that; delay an input signal by multiple delays; process the multiply delayed input signal in a partitioned adaptive filter comprising multiple adaptive filter outputs; bias an adaptive filter output signal received from at least one of the adaptive filter outputs to generate a gain-weighted adaptive filter output signal from the adaptive filter output signal; generate a summed adaptive filter output signal after biasing, where the summed adaptive filter output signal comprises a sum of the gain-weighted adaptive filter output signal and at least one other adaptive filter output signal; and reinforce periodic signal content in the input signal with the summed adaptive filter output signal by adding the summed adaptive filter output signal to the input signal to increase a first periodic signal component in the input signal that is at least partially in-phase with a second periodic signal component in the summed adaptive filter output signal. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28)
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29. A pitch detector comprising:
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a processor; a signal input; an adaptive filter coupled to the signal input, the adaptive filter comprising filter coefficients and operable to adapt based on an error signal; pitch detection logic coupled to the adaptive filter, where the processor is configured to execute the pitch detection logic and find a peak in the filter coefficients and produce a pitch estimate based on the position of the peak; and a pitch estimate output coupled to the pitch detection logic. - View Dependent Claims (30, 31, 32, 33, 34)
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35. A method for pitch detection comprising:
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receiving an input signal; filtering the input signal through an adaptive filter; updating filter coefficients in the adaptive filter based on an error signal; determining a peak in the filter coefficients by a pitch detector comprising a non-transitory computer-readable medium or circuit; producing a pitch estimate based on the position of the peak. - View Dependent Claims (36, 37, 38, 39, 40)
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41. A voice detector comprising:
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a processor; a signal input; an adaptive filter coupled to the signal input, the adaptive filter comprising filter coefficients and operable to adapt based on an error signal; voice detection logic coupled to the adaptive filter, where the processor is configured to execute the voice detection logic to analyze the filter coefficients of the adaptive filter to determine a detection measure based on the filter coefficients of the adaptive filter, where the voice detection logic is operable to analyze the detection measure to detect whether voiced speech is present in a signal received on the signal input; a voice detection output coupled to the voice detection logic. - View Dependent Claims (42, 43, 44, 45)
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46. A method for voice detection comprising:
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receiving an input signal; filtering the input signal through an adaptive filter; updating filter coefficients in the adaptive filter based on an error signal; analyzing the filter coefficients of the adaptive filter to determine a detection measure based on the filter coefficients of the adaptive filter, where the act of analyzing the filter coefficients is performed by a voice detector comprising a non-transitory computer-readable medium or circuit; analyzing the detection measure to detect whether periodic components are present in the input signal; and asserting a voice detection output based on a determination that the detection measure is above a threshold. - View Dependent Claims (47, 48, 49, 50)
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Specification