Abstract: Apparatus and method for transmitting and reproducing stereophonic audio signals are disclosed. The method comprises splitting first and second channels into two frequency bands, combining the lower frequency band signals of the two channels, and transmitting the combined signals of the two channels or signals representative thereof. The apparatus comprises: a splitter for splitting each of the two channels into two frequency bands, a combiner, for combining the lower frequency band signals of the two channels, and a transmitter for transmitting the combined signals, or signals representative thereof, and the higher frequency band signals of the two channels, or signals representative thereof.

Abstract: A sound transmission system comprises-a microphone, an amplifier, a low-pass filter, an ADC, a digital signal processor (DSP), a digital interface, a buffer, and a transport medium interface. The low-pass filter removes unwanted out-of-band signals, and the ADC converts the filtered analog signal to digital form. The DSP receives the digital data from the ADC and performs gain and filtering operations in the digital domain. The digital interface operates on the data and places it on the buffer where the data is stored prior to being transmitted over some channel via the transport medium interface. By powering down one or more particular components of the sound transmission system, most notably the ADC, the DSP and the digital interface, when the received signal falls below a predetermined level, power consumption is reduced.

Abstract: A communications system comprises a PDA and a Bluetooth peripheral device. The Bluetooth peripheral device is connected to the PDA by a data channel. The Bluetooth peripheral device enables the PDA to communicate with remote data networks using the Bluetooth wireless protocol. The system is configured to operate according to an algorithm that enables the Bluetooth peripheral device to enter an ultra-low power mode in which a receiver associated with data transfer can be disabled when no data is required to be transmitted. Data loss is prevented through the use of a hardware handshake mechanism that stops the PDA from sending data while the Bluetooth peripheral device is in the low power mode. Latency in the PDA responding to a change in handshake signals is provided.

Abstract: A data processing system is disclosed including a data processor for operating on data samples received from a data source, a digital to analog converter arranged to receive the data samples from the data processor and to convert the received data samples into an analog signal, and a controller arranged to monitor the magnitude of the data samples received from the data source and disable one or both of the data processor means and the digital to analog converter when the magnitude of one or more received data samples falls within a predetermined magnitude range. Such a system is able to operate in a low-power mode that may be advantageous for battery-powered device or other applications where power conservation is important.

Abstract: Apparatus and method for transmitting and reproducing stereophonic audio signals are disclosed. The method comprises splitting first and second channels into two frequency bands, combining the lower frequency band signals of the two channels, and transmitting the combined signals of the two channels or signals representative thereof. The apparatus comprises: a splitter for splitting each of the two channels into two frequency bands, a combiner, for combining the lower frequency band signals of the two channels, and a transmitter for transmitting the combined signals, or signals representative thereof, and the higher frequency band signals of the two channels, or signals representative thereof.