Technique for encoding multi-level signals

Apparatus for encoding a series of samples of a multilevel communication signal each having one of at least three different values, including:

• means for generating a first series of run length code words which indicate the sequence of occurrence of (1) ones of said samples having a first one of said different values which occurs more frequently than any other of said different values, and (2) other ones of said samples having other ones of said values, and for generating a second series of code words indicating the values of said other ones of said samples, and
• means for combining said first and second series of code words.

Apparatus for encoding a series of samples of a multi-level error signal derived from a predictive encoder, including

• means for grouping said samples so as to form alternate runs of (1) samples having the most frequently occurring predetermined value and (2) samples having all remaining, less frequently occurring values, and
• means for encoding (a) the length of each of said runs, and (b) the values of only said samples having said remaining, less frequently occurring values.

A method of encoding samples of a multilevel communication signal, each sample having one of at least M (M.gtoreq.3) different values, wherein the statistical likelihood of a particular one of said values is much greater than the statistical likelihood of any other of said values, including the steps of:

• grouping said samples in runs of a first or a second type, wherein said first type runs include one or more consecutive samples of said particular value and said second type runs include one or more consecutive samples of said other values, and
• generating an output signal representing said multilevel signal by encoding the lengths of said runs and a representation of said other values.

The method of encoding a series of samples of a multilevel communication signal, each sample having one of at least three different values, including the steps of:

• generating a first series of run length code words which indicate the sequence of occurrence of (1) ones of said multilevel samples having a first one of said different values which occurs more frequently than any other of said different values, and (2) other ones of said samples, and generating a second series of code words indicating the values represented by said other ones of said samples, and
• generating an output signal by combining said first and second series of code words.

A method of encoding a series of words which represent samples of a multi-level signal representing pictorial information, including the steps of:

• grouping said words so as to form alternate runs of (1) words having the most frequently occurring predetermined value and (2) words having all remaining, less frequently occurring value, and
• generating an output signal which represents said pictorial information by encoding (a) the length of each of said runs, and (b) the values of only said words having said remaining, less frequently occurring values.