Abstract: Various sensors, sensor controllers, and sensing methods are suitable for use in a multi-channel ultrasonic sensor array such as those used in systems for parking assistance, blind spot monitoring, and driver assistance. One illustrative acoustic sensing method includes: driving an acoustic transducer to send acoustic bursts each including an up-chirp in a first frequency band and a down-chirp in a second frequency band; receiving echo signals responsive to the acoustic bursts from the transducer; and using the echo signals to determine a distance or time of flight from the transducer. Another acoustic sensing method includes: driving an acoustic transducer to send acoustic bursts each including a concurrent up-chirp and down-chirp; receiving echo signals responsive to the acoustic bursts from the transducer; and using the echo signals to determine a distance or time of flight from the transducer.

Abstract: An illustrative controller includes: a transmitter to drive the acoustic transducer to generate acoustic bursts; a receiver to sense a response of the acoustic transducer to echoes; and a processing circuit coupled to the transmitter and to the receiver, the processing circuit configured to convert said received response into output data by: correlating said response to a driving signal to obtain a correlation response; distinguishing peak areas from non-peak areas in said correlation response; deriving a noise level in a portion of said correlation response based on the non-peak areas within said portion; calculating a signal to noise ratio (SNR) for a peak signal within the portion as a ratio of a peak value for the peak signal to the noise level in said portion of said correlation response; and accepting the peak signal as an echo only if the SNR for said peak signal exceeds a predetermined threshold.