Coexistence of ultrasonic transducers in an operating environment

A sensor processing unit comprising:

• an ultrasonic transducer configured to repeatedly emit ultrasonic pulses during transmit periods which are interspersed with listening windows, wherein each sequential pair of the transmit periods is separated by a single listening window of the listening windows, and wherein during a fixed portion of a listening window of the listening windows the ultrasonic transducer is configured to receive returned signals corresponding to an emitted ultrasonic pulse of the ultrasonic pulses which was transmitted during a transmit period of the transmit periods which immediately preceded the listening window;
• and
• a sensor processor coupled with the ultrasonic transducer and configured to:
• randomize, by the sensor processor, an overall length of each listening window of the listening windows;
• direct, by the sensor processor, filtering of returned signals received during a plurality of the randomized listening windows to achieve filtered returned signals;
• and
• detect, by the sensor processor using the filtered returned signals, a moving object in a field of view of the ultrasonic transducer.

A method of operating an ultrasonic transducer to facilitate coexistence with other ultrasonic transducers in the operating environment of the ultrasonic transducer, the method comprising:

• controlling, by a processor, the ultrasonic transducer to repeatedly emit ultrasonic pulses during transmit periods which are interspersed with listening windows, wherein each sequential pair of the transmit periods is separated by a single listening window of the listening windows, and wherein during a portion of a listening window, of the listening windows, the ultrasonic transducer is configured to receive returned signals corresponding to an emitted ultrasonic pulse of the ultrasonic pulses which was transmitted during a transmit period of the transmit periods that immediately preceded the listening window;
• randomizing, by the processor, an overall length of each listening window of the listening windows;
• filtering returned signals received during a plurality of the randomized listening windows to achieve filtered returned signals;
• and
• detecting, by the processor using the filtered returned signals, a moving object in a field of view of the ultrasonic transducer despite interference from one or more of the other ultrasonic transducers transmitting ultrasonically in the operating environment.