Digital data transmission involving the position of and duration of data pulses within transfer periods

摘要

Methods and apparatus for transmission of multiple digital data streams, such as digital audio data over a single communications link such as a single wire. At least two data inputs receive digital data streams (PDM-R, PDM-L), of data bits, from which a pulse generator generates single data pulses (PLM) having a rising edge and falling edge occurring within each of a plurality of transfer periods defined by a first clock signal (TCLK). The timing of the rising and falling edge of each data pulse is dependent upon on a combination of the then current data bits from the plurality of data streams. The duration and position of the data pulse in the transfer window in effect defines a data symbol encoding the data. Circuitry for receiving and extracting the data is also disclosed. An interface receives the stream of data pulses (PLM) and data extraction circuitry (202) samples the data pulse to determine which of the possible data symbols the pulse represents and determines a data value for at least one received data stream. The invention can allow for low latency data transfer, which is advantageous for noise cancellation systems.