PULSE CODE MODULATION SYSTEM FOR HYBRID MULTIPLEX TRANSMISSION OF AUDIO AND DATA SIGNALS

• US 3,720,791 A
• Filed: 03/29/1968
• Issued: 03/13/1973
• Est. Priority Date: 03/31/1967
• Status: Expired due to Term

• Current Assignee: Shinichi Mitsui, Tsukumo Higeta, Yutaka Yada
• Original Assignee: Shinichi Mitsui, Tsukumo Higeta, Yutaka Yada
• Inventors: Yada, Yutaka, Higeta, Tsukumo, Mitsui, Shinichi
• Primary Examiner(s): Blakeslee, Ralph D.
• Application Number:
  US04/717,176
• Time in Patent Office: 1,810 Days
• Field of Search: 179/15A,15BA,15BY,2DP,15BS,15BW 340/347 325/38A 178/6BW
• US Class Current: 370/301
• CPC Class Codes: H04L 25/493 by transition coding, i.e. the time-position or direction of a transition being encoded before transmission
• CPC Class Codes: H04L 5/225 combined with the use of transition coding transition coding H04L25/493

Abstract

Clock signals divide asynchronous signals of two levels into equal time slots. The condition of the asynchronous signal is detected at a determined instant in a time slot so that it also determines a change in condition of the signal. The condition of the signal is indicated in a specific code indication depicting such condition and a change in condition of the signal is indicated in a different code indication depicting the instant of change of condition in a time slot. The code indications are transmitted mixed with PCM signals.

Claims

1. A digital communications system for converting and transmitting asynchronous signals of two levels by synchronous digital transmission, comprising clock means for dividing asynchronous signals of two levels into equal time slots;

detecting means for detecting the condition of said asynchronous signal at a determined instant in a time slot thereby also determining a change in condition of said signal;

encoding means connected to said detecting means for indicating the condition of said signal in a specific code indication consisting of plural binary digits and depicting said condition and for indicating a change in condition of said signal in a different code indication consisting of plural binary digits and depicting the insTant of change of condition in a time slot, said encoding means comprising converter means for converting the asynchronous signals in equal time slots into synchronizing pulses of n bits;

transmitting means connected to said encoding means for transmitting said code indications; and

further clock means for subdividing the time slots into 2n - 2 subdivisions each, the code indication depicting the instant of change of condition being placed in said subdivisions.

2. In a pulse code modulation system for hybrid multiplex transmission of audio and data signals clock means for dividing asynchronous data signals of two levels into equal time slots;

detecting means for detecting the condition of said asynchronous signal at a determined instant in a time slot thereby also determining a change in condition of said signal;

encoding means connected to said detecting means for indicating the condition of said signal in a specific code indication consisting of plural binary digits and depicting said condition and for indicating a change in condition of said signal in a different code indication consisting of plural binary digits and depicting the instant of change of condition in a time slot, said encoding means comprising converter means for converting the asynchronous signals in equal time slots into synchronizing pulses of n bits;

multiplexing means connected to said encoding means for time division multiplexing said code indications;

transmitting means connected to said multiplexing means for transmitting the time division multiplexed signals; and

further clock means for subdividing the time slots into 2n - 2 subdivisions each, the code indication depicting the instant of change of condition being placed in said subdivisions.