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US 2009/0213696 A1Published application
Echo detection
AssigneeAMI Semiconductor Belgium BVBA
InventorIvan Koudar
Life of this patent
Estimating the term…
Abstract
An echo detection circuit that detects an echo by detecting the magnitude of a digitally mixed representation of the received acoustic signal and reference sine and cosine signals. That magnitude is then compared against an echo threshold to verify the presence or absence of an echo signal. A low pass filter with a configurable cut-off frequency may be used to define the selectivity of the echo detector.
Claims16
An echo detection circuit comprising:
- an acoustic sensor configured to convert sensed acoustic pressures into a pre-processed analog electrical signal;
- analog processing circuitry configured to transform the pre-processed analog electrical signal into a post-processed analog electrical signal suitable for providing to an analog-to-digital converter;
- an analog to digital converter configured to convert the post-processed analog electrical signal into a digital signal;
- a sine mixer configured to digitally mix the digital signal provided by the analog to digital converter with a sine wave of approximately the same frequency as a carrier wave of a transmitted acoustic signal whose echo is being detected;
- a cosine mixer configured to digitally mix the digital signal provided by the analog to digital converter with a cosine wave of approximately the same frequency as the carrier wave of the transmitted acoustic signal whose echo is being detected;
- a vector magnitude detection mechanism that detects a magnitude of the vector represented by at least a derivative of a signal received from the sine mixer, and at least a derivative of a signal received from the cosine mixer;
- and
- a threshold detection circuit that compares the magnitude of the vector with one or more thresholds to determine whether or not an echo is detected.
5 more elements
An echo circuit comprising:
- a resonator;
- an acoustic transmitter that is configured to transmit an acoustic signal at a particular frequency;
- an echo detection circuit that uses the resonator to convert detected acoustic pressures and convert such pressures into an analog signal that may be used to detect echoes from the acoustic signal transmitted by the acoustic transmitter, the echo detection circuit comprising:
- an analog to digital converter configured to convert at least a derivative of the analog signal into a digital signal;
- a sine mixer configured to digitally mix the digital signal provided by the analog to digital converter with a digital sine wave;
- a cosine mixer configured to digitally mix the digital signal provided by the analog to digital converter with a digital cosine wave;
- a vector magnitude detection mechanism that detects a magnitude of the vector represented by at least a derivative of a signal received from the sine mixer, and at least a derivative of a signal received from the cosine mixer;
- and
- a threshold detection circuit that compares the magnitude of the vector with one or more thresholds to determine whether or not an echo is detected;
- and
- a clock configured to control the transmission frequency of the acoustic transmitter, the oversampling ratio of the analog to digital converter, and the mixing rate of the sine mixer and the cosine mixer.
8 more elements
Dependencies are inferred from the claim text.