Robust feature extraction using differential zero-crossing counts
AssigneeTexas Instruments Incorporated
InventorsZhenyong Zhang, Wei Ma
Life of this patent
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Abstract
A low power sound recognition sensor is configured to receive an analog signal that may contain a signature sound. Sparse sound parameter information is extracted from the analog signal and compared to a sound parameter reference stored locally with the sound recognition sensor to detect when the signature sound is received in the analog signal. A portion of the sparse sound parameter information is differential zero crossing (ZC) counts. Differential ZC rate may be determined by measuring a number of times the analog signal crosses a threshold value during each of a sequence of time frames to form a sequence of ZC counts and taking a difference between selected pairs of ZC counts to form a sequence of differential ZC counts.
Claims7
A process comprising:
- (a) receiving an analog signal in channel circuitry;
- (b) producing a comparison output signal by comparing the received analog signal to an amplitude of a threshold voltage, the comparison output signal indicating the received analog signal crossing the amplitude of the threshold voltage;
- (c) counting in counter circuitry at a counting clock frequency the number of times the comparison output signal indicates the received analog signal exceeds the amplitude of the threshold voltage comparison output;
- (d) transferring a count from the counter circuitry to buffer circuitry at a frame clock frequency, the transferring including resetting the count of the counter circuitry;
- (e) taking a difference in subtractor circuitry between a count in the counter circuitry and a count in the buffer circuitry to result in a differential zero crossing count output;
- and
- (d) comparing the differential zero crossing count output to counts in a sound parameter database.
Dependencies are inferred from the claim text.