US 4,410,980 AGranted

Time division multiplexing system

AssigneeHitachi, Ltd.

InventorsYoshitaka Takasaki, Mitsuo Tanaka

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Abstract

In a time division multiplexing system for multiplexing a plurality of channels having mutually-independent bit rates, the improvement wherein the pulse signals of each channel are converted into codes so that the information "1" is represented by a pulse having a width of two consecutive transmission clock periods ("0,0" or "1,1") the information "0" is represented by a pluse having a width of a single transmission clock period ("0" or "1"), and polarities of adjacent pulses are always different from each other; the pulse signals are compressed time-wise in a frame unit; and a frame synchronizing signal and a channel synchronizing signal, each consisting of marks or spaces having a duration of at least three consecutive transmission clock periods, are added to the intervals between the time-compressed frames to thereby perform time division multiplexing.

Claims10

Dependent claims

A time division multiplexing system comprising:

a plurality of digital signal sources for providing a plurality of channels of digital data at mutually independent selected bit rates;
time compression means including a plurality of converter circuits for compressing in time the digital signals of each channel for a given frame period to produce respective compressed data channels;
time division multiplexing means for adding a frame synchronizing signal to the output of one of said converter circuits and a channel synchronizing signal to the outputs of the other ones of said converter circuits and for conducting time division multiplexing of the compressed data channels, including means for adding a stuff pulse to one of the multiplexed data channels so that the total duration time of said compressed data from all channels, said frame and channel synchronizing signals and the stuff pulse coincides with a transmission frame period;
said converter circuits each including coding means for coding the output of said time compression means to convert said input digital signals into coded signals in which a mark and a space are designated by different pulse intervals;
a transmission line for transmitting the output of said multiplexing means;
and decoding means for decoding the time division multiplexed signal transmitted by said transmission line.

3 more elements

A time division multiplexing system for multiplexing a plurality of input digital signals having mutually independent selected bit rates to produce a multiplexed output signal at a transmission bit rate which is higher than the bit rate of any of said input digital signals, comprising

clock generator means for generating clock signals at said transmission bit rate and frame signals;
a plurality of code converters, each connected to simultaneously receive a respective one of said input digital signals and including means for storage of said input digital signals during alternate periods between successive frame signals, means for reading-out the data stored in said storage means during the periods between said alternate periods at the rate of said clock signals and means for coding said data at the time of read-out from said storage means;
means for controlling the read-out of data in each code converter so that said code converts effect the read-out of data sequentially, including means responsive to the read-out of one frame of data in one code converter for generating a start signal initiating the operation of the reading-out means in another code converter;
and
means for combining the outputs of said code converters.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/289,106Filed 31 Jul 1981
Priority: JP 55-1049881 Aug 1980
Granted: 18 Oct 1983
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

H04J 3/16
Time-division multiplex systems: in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate…
H04J 3/073
Using pulse stuffing for systems with different or fluctuating information rates or bit rates: bit stuffing, e.g. PDH
H04L 5/24
Using time-division multiplexing: with start-stop synchronous converters
H04L 25/4912
Using 1B2B codes: using CMI or 2-HDB-3 code