Abstract: A signal processing method and apparatus are described for demultiplexing selected components (especially audio signals) from a multiplexed data stream. Each of the desired channel components has a unique identification code detected by a processor parsing the contents of a received data buffer between the disc reader and the demultiplexer. The demultiplexer is set up to output received data channel streams having a specific identification code different from any of those assigned to the channel streams originally. Prior to demultiplexing, the identification code for a desired one of the channel streams is altered by the processor to the specific identification code as it passes through the buffer in order to avoid re-setting the demultiplexer.

Abstract: A music emulator for emulating guitar sounds uses non-guitar like devices, as for instance a piano style keyboard, for input. Input from the keyboard within a time window is defined as simultaneous and entered into a note list. A signal is derived from the note list indicative of the chord played on the keyboard. In addition, notes in the note list can be extended to form a full chord whereby as few as three notes constituting a chord input at the keyboard are extended to a greater number of notes as, for instance, the six strings of a guitar. This signal is then outputted at a time rate which is extended with respect to the input time window whereby the output emulates a guitar strum including an arpeggiation or strumming effect of a guitar like sound. Chord extension is achieved by analyzing the notes in the note list as to their pitch and generating further notes which are outside the typical one octave range of a keyboard chord and extend to the typical four octave window of a guitar.