Methods and apparatus for encoding and constructing signals

A method of encoding an input signal having at least an alternating component comprising the steps of:

• generating a succession of first signals, each of said first signals being related to the duration of a corresponding sub-division of said input signal;
• generating a succession of second signals, each of said second signals being one of a set of predetermined signals and related to at least one characteristic of waveform shape of a corresponding said sub-division, said sub-divisions being defined by any predetermined characteristic of said input signal waveform so long as said input signal alternating component does not have more than three zero crossings in any of said sub-divisions, and the encoding being such that a useful reconstruction of a signal which has been encoded can be carried out from said first and second signals only.

Apparatus for encoding an input signal, comprising:

• means for generating a succession of first signals, each of said first signals being related to the duration of a corresponding sub-division of said input signal;
• means for generating a succession of second signals, each second signal being one of a set of predetermined signals and being related to at least one characteristic of waveform shape of a corresponding sub-division, each said sub-division being defined by any predetermined characteristic of said input signal waveform so long as said input signal alternating component does not have more than three zero crossings in any of said sub-divisions, and the apparatus being such that a useful reconstruction of a signal which has been encoded can be carried out from said first and second signals only.

A method of constructing an output signal having at least an alternating component from a succession of first signals related to the duration of sub-divisions of said output signal, and a succession of second signals related to at least one characteristic of shape of said output signal sub-divisions, the method comprising the step of generating an analogue signal having sub-divisions of durations related to said first signals, each said sub-division of said analogue signal having a shape related to a corresponding one of said second signals, said sub-divisions being defined by any predetermined characteristic of said output signal waveform so long as said output signal alternating component does not have more than three zero crossings in any of said sub-divisions.

Apparatus for constructing an output signal having at least an alternating component from a succession of first signals related to the duration of sub-divisions of said output signal, and a succession of second signals related to at least one characteristic of shape of said output signal sub-divisions, the apparatus comprising means for generating an analogue signal having subdivisions with durations related to said first signals, each said sub-division of said analogue signal having a shape related to a corresponding one of said second signals, each said sub-division being defined by any predetermined characteristic of said output signal waveform so long as said output signal alternating component does not have more than three zero crossings in any of said sub-divisions.

Apparatus for encoding varying signals comprising a computer programmed to encode said varying signals by generating a succession of first signals, each of which represents the duration of a sub-division of a signal to be encoded, and generating a succession of second signals, each second signal being one of a set of predetermined signals, each of which represents at least one characteristic of waveform shape of a said sub-division of the signal to be encoded, each said sub-division being any portion of the signal to be encoded which is defined in any systematic way which depends on a characteristic of the signal waveform and which results in sub-divisions having not more than three zero crossings in the alternating component of the signal to be encoded.

Apparatus for encoding varying signals comprising a computer programmed to construct a signal from a succession of first signals each representing the duration of a sub-division in a specific signal, and a succession of second signals, each representing at least one characteristic of shape of a said sub-division of the specific signal, the computer generating an analogue signal having sub-divisions of durations derived from durations as represented by the said first signals, each said sub-division of the analogue signal having a shape derived from a shape as represented by a second signal, the said sub-divisions in the specific signal and the analogue signal each being any portion of the signal which is defined in any systematic way which depends on a characteristic of the signal waveform and which results in sub-divisions having not more than three zero crossings in the alternating component of the signal.