Abstract: A portable electronic device comprises means 4 for transmitting ultrasonic signals 8, means 6 for receiving ultrasonic signals 12 reflected from an input object 10, and means for processing received ultrasonic signals to determine an input to the device. The device is configured to reduce the transmission power of the ultrasonic signals transmitted by the transmitting means in the event that: the device determines that a reflection 16 from an object 14 other than the input object meets a predetermined criterion; or if an event is detected which indicates that the user is or will be using a function of the device which does not support touchless interaction.

Abstract: An electronic device comprises a transmitter 6 for transmitting ultrasonic signals, a receiver 8 for receiving reflections 20 of said ultrasonic signals, wherein the device is adapted to control a function thereof in dependence on said received reflections, the device further comprising means for providing to a user an indication 14 of the presence of signals or noise which could interfere with said reflections.

Abstract: A user input to a system is processed by receiving reflections of signals from a moving input object. Information relating to the direction of movement of the input object and information relating to the speed of the input object are determined from the reflections. Continual sensory feedback is provided to the user, controlled by a parameter that is repeatedly updated based on the direction and speed of the input object. When no new determination of information relating to the speed or direction of the input object has been made since a previous update, a time-dependent change is made to the parameter.

Abstract: A portable electronic device comprises means 4 for transmitting ultrasonic signals 8, means 6 for receiving ultrasonic signals 12 reflected from an input object 10, and means for processing received ultrasonic signals to determine an input to the device. The device is configured to reduce the transmission power of the ultrasonic signals transmitted by the transmitting means in the event that: the device determines that a reflection 16 from an object 14 other than the input object meets a predetermined criterion; or if an event is detected which indicates that the user is or will be using a function of the device which does not support touchless interaction.

Abstract: Estimating the impulse response of a channel by providing an initial signal (20); applying a time-shift function to the initial signal (20) to produce a transmit signal (36); transmitting the transmit signal (36); receiving a received signal; calculating an impulse response from the received signal as if the received signal had been produced by the initial signal; and using the impulse response to distinguish between received signals arising from reflections from objects (6) at different ranges.

Abstract: An electronic device comprises a transmitter 6 for transmitting ultrasonic signals, a receiver 8 for receiving reflections 20 of said ultrasonic signals, wherein the device is adapted to control a function thereof in dependence on said received reflections, the device further comprising means for providing to a user an indication 14 of the presence of signals or noise which could interfere with said reflections.

Abstract: Estimating the impulse response of a channel by providing an initial signal (20); applying a time-shift function to the initial signal (20) to produce a transmit signal (36); transmitting the transmit signal (36); receiving a received signal; calculating an impulse response from the received signal as if the received signal had been produced by the initial signal; and using the impulse response to distinguish between received signals arising from reflections from objects (6) at different ranges.