Sound sensing with time-varying thresholds
AssigneeTexas Instruments Incorporated
InventorsLei Ding, Srinath Mathur Ramaswamy
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Abstract
An ultrasonic sensing system includes: an amplifier including an input and an output; and an n-level comparator, coupled to the output of the amplifier, to compare an adjustable threshold voltage to an output signal from the output of the amplifier. N is greater than or equal to 1. The system also includes a noise power estimator, coupled to an output of the n-level comparator, to generate a noise power signal indicative of noise power of an input signal at the input of the amplifier. The system further includes a time-varying threshold circuit, coupled to the noise power estimator and the n-level comparator, to adjust the adjustable threshold voltage based on the noise power signal.
Claims21
An ultrasonic sensing system, comprising:
- an amplifier including an input and an output;
- an n-level comparator, coupled to the output of the amplifier, to compare an adjustable threshold voltage to an output signal from the output of the amplifier, wherein n is greater than or equal to 1;
- a noise power estimator, coupled to an output of the n-level comparator, to generate a noise power signal indicative of noise power of an input signal at the input of the amplifier;
- and
- a time-varying threshold circuit, coupled to the noise power estimator and the n-level comparator, to adjust the adjustable threshold voltage based on the noise power signal and based on a signal indicative of a gain configuration of the amplifier.
An ultrasonic sensing system, comprising:
- an amplifier including an input and an output;
- an analog-to-digital converter (ADC), coupled to the output of the amplifier, to generate a digital output in response to an analog output signal from the output of the amplifier, wherein the ADC is an n-bit converter;
- a bit reduction circuit, coupled to the ADC, to reduce a number of bits of the digital output based on time-varying thresholds;
- a noise power estimator, coupled to the ADC, to generate a noise power signal indicative of noise power of an input signal at the input of the amplifier;
- and
- a time-varying threshold circuit, coupled to the noise power estimator and the bit reduction circuit, to adjust the time-varying thresholds based on the noise power signal.
An ultrasonic sensing system, comprising:
- an amplifier including an input and an output;
- an n-level comparator, coupled to the output of the amplifier, to compare an adjustable threshold voltage to an output signal from the output of the amplifier, wherein n is greater than or equal to 1;
- a noise power estimator, coupled to an output of the n-level comparator, to generate a noise power signal indicative of noise power of an input signal at the input of the amplifier;
- a time-varying threshold circuit, coupled to the noise power estimator and the n-level comparator, to adjust the adjustable threshold voltage based on the noise power signal;
- a correlator circuit to correlate the output of the n-level comparator with a template signal, and to generate a correlator output signal in response thereto;
- an envelope detector, coupled to the correlator circuit, to generate an envelope signal in response to the correlator output signal;
- and
- a comparator, coupled to the envelope detector, to compare the envelope signal to a threshold map signal that defines a time-varying threshold.
Dependencies are inferred from the claim text.