Method and apparatus for encoding a binary digital information signal

A method of encoding a binary digital information signal comprised of m-bit information words occurring within a frequency band to produce an encoded binary digital information signal comprised of n-bit channel words, each n-bit channel word being comprised of an n-bit information word where n.sub.1 >m and an n.sub.2 -bit separation word, and said encoded binary digital information signal having a format with substantially reduced components thereof in a predetermined frequency range of said frequency band, said method comprising the steps of:

• converting each m-bit information word into an n.sub.1 -bit information word;
• generating a set of possible n.sub.2 -bit separation words for use with each n.sub.1 -bit information word;
• separately adding each possible n.sub.2 -bit separation word to each n.sub.1 -bit information word, to provide at least one n-bit channel word corresponding to each n.sub.1 -bit information word;
• determining an integrating transfer function characteristic including information with respect to said predetermined frequency range;
• modifying each said n-bit channel word by said integrating transfer function characteristic to produce a step response;
• evaluating said step response at at least one predetermined evaluation time to obtain a parameter having an overall value including information with respect to said predetermined frequency range;
• selecting the one of said possible n.sub.2 -bit separation words for each of said n.sub.1 -bit information words that yields a value of said parameter which is closest to zero;
• and
• adding said selected ones of said possible n.sub.2 -bit separation words following each respective one of said n.sub.1 -bit information words to form said encoded binary digital information signal having said format with substantially reduced components thereof in said predetermined frequency range.

A method of encoding a binary digital information signal comprised of m-bit information words occurring within a frequency band to produce an encoded binary digital information signal comprised of n-bit channel words, each n-bit channel word being comprised of an n.sub.1 -bit information word where n.sub.1 >m and an n.sub.2 -bit separation word, and such that, in a continuous stream of said channel words, a d-constraint rule is satisfied in which a minimum of d consecutive bits of one type exist between bits of the other type and a k-constraint rule is satisfied in which a maximum of k consecutive bits of said one type exist between said bits of the other type, and said encoded binary digital information signal is produced with substantially reduced components thereof in a predetermined frequency range of said frequency band, said method comprising the steps of:

• converting each m-bit information word into an n.sub.1 -bit information word;
• generating a set of possible n.sub.2 -bit separation words for use with each n.sub.1 -bit information word so that said d-constraint rule and said k-constraint rule are satisfied;
• separately adding each possible n.sub.2 -bit separation word to each n.sub.1 -bit information word, to provide at least one n-bit channel word corresponding to each n.sub.1 -bit information word;
• determining an integrating transfer function characteristic including information with respect to said predetermined frequency range;
• modifying each said n-bit channel word by said integrating transfer function characteristic to produce a step repsonse;
• evaluating said step response at at least one predetermined evaluation time to obtain a parameter having an overall value including information with respect to said predetermined frequency range;
• selecting the one of said possible n.sub.2 -bit separation words for each of said n.sub.1 -bit information words that yields a value of said parameter which is closest to zero;
• and
• adding said selected ones of said possible n.sub.2 -bit separation words following each respective one of said n.sub.1 -bit information words to form said encoded binary digital information signal having said format with substantially reduced components thereof in said predetermined frequency range.

Apparatus for encoding a binary digital information signal comprised of m-bit information words occurring within a frequency band to produce an encoded binary digital information signal comprised of n-bit channel words, each n-bit channel word being comprised of an n.sub.1 -bit information word where n.sub.1 >m and an n.sub.2 -bit separation word, and said encoded binary digital information signal having a format with substantially reduced components thereof in a predetermined frequency range of said frequency band, said apparatus comprising:

• means for converting each m-bit information word into an n.sub.1 -bit information word;
• means for generating a set of possible n.sub.2 -bit separation words for use with each n.sub.1 -bit information word;
• means for generating an evaluation signal corresponding to at least one parameter of a step response produced by modifying each n.sub.2 -bit information word and each respective possible n.sub.2 -bit separation word by an integrating transfer function characteristic including information with respect to said predetermined frequency range;
• means for selecting one of said possible n.sub.2 -bit separation words for each respective n.sub.1 -bit information word in response to said evaluation signal;
• and
• means for adding each said selected one of said possible n.sub.2 -bit separation words following each respective one of said n.sub.1 -bit information words to form said encoded binary digital information signal having said format with substantially reduced components thereof in said predetermined frequency range.

A method of decoding an encoded binary digital information signal comprised of n-bit channel words, during reproduction, each n-bit channel word being comprised of an n.sub.1 -bit information word and an n.sub.2 -bit separation word, the encoded binary digital information signal having a synchronizing signal added thereto and having a format with substantially reduced components thereof in a predetermined frequency range, to form an original binary digital information signal comprised of m-bit information words where n.sub.1 >m, said method comprising the steps of:

• detecting said synchronizing signal;
• extracting said encoded binary digital information signal in response to said detection of said synchronizing signal;
• separating each of said n.sub.1 -bit information words from each of said n-bit channel words comprising said extracted encoded binary digital information signal;
• and
• converting each separated n.sub.1 -bit information word to a corresponding m-bit information word to form said original binary digital information signal.

Apparatus for decoding an encoded binary digital information signal comprised of n-bit channel words, during reproduction, each n-bit channel word being comprised of an n-.sub.1 -bit information word and an n.sub.2 -bit separation word, the encoded binary digital information signal having a synchronizing signal added thereto and having a format with substantially reduced components thereof in a predetermined frequency range, to form an original binary digital information signal comprised of m-bit information words where n.sub.1 >m, said apparatus comprising:

• means for detecting said synchronizing signal;
• means for extracting said encoded binary digital information signal in response to said detection of said synchronizing signal;
• means for separating each of said n.sub.1 -bit information words from each of said n-bit channel words comprising said extracted encoded binary digital information signal;
• and
• means for converting each separated n.sub.1 -bit information word to a corresponding m-bit information word to form said original binary digital information signal.