GB1371615A

GB1371615A – Digital data transmission systems and apparatus therefore
– Google Patents

GB1371615A – Digital data transmission systems and apparatus therefore
– Google Patents
Digital data transmission systems and apparatus therefore

Info

Publication number
GB1371615A

GB1371615A
GB680072A
GB680072A
GB1371615A
GB 1371615 A
GB1371615 A
GB 1371615A
GB 680072 A
GB680072 A
GB 680072A
GB 680072 A
GB680072 A
GB 680072A
GB 1371615 A
GB1371615 A
GB 1371615A
Authority
GB
United Kingdom
Prior art keywords
disparity
digits
signal
words
excluded
Prior art date
1971-12-08
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)

Expired

Application number
GB680072A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)

General Electric Co PLC

Original Assignee
General Electric Co PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
1971-12-08
Filing date
1973-02-14
Publication date
1974-10-23

1971-12-08
Priority claimed from GB5828870A
external-priority
patent/GB1371614A/en

1973-02-14
Application filed by General Electric Co PLC
filed
Critical
General Electric Co PLC

1973-02-14
Priority to GB680072A
priority
Critical
patent/GB1371615A/en

1974-10-23
Publication of GB1371615A
publication
Critical
patent/GB1371615A/en

Status
Expired
legal-status
Critical
Current

Links

Espacenet

Global Dossier

Discuss

Classifications

H—ELECTRICITY

H04—ELECTRIC COMMUNICATION TECHNIQUE

H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION

H04L25/00—Baseband systems

H04L25/38—Synchronous or start-stop systems, e.g. for Baudot code

H04L25/40—Transmitting circuits; Receiving circuits

H04L25/49—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems

H04L25/4917—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems using multilevel codes

H04L25/4919—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems using multilevel codes using balanced multilevel codes

H—ELECTRICITY

H04—ELECTRIC COMMUNICATION TECHNIQUE

H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION

H04L25/00—Baseband systems

H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines

H04L25/12—Compensating for variations in line impedance

Abstract

1371615 Digital transmission; multi-level coding GENERAL ELECTRIC CO Ltd 14 Feb 1973 [8 Dec 1971 14 Feb 1972] 8307/72 and 6800/72 Heading H4P In an arrangement converting a binary signal to N= at least 4 levels, input words of A digits is represented by B digits where N B is greater than 2A and all output words have at least one digit, which may be the first, of maximum disparity. In one embodiment N = 4, A=6 and B=4. At the receiver an amplifier having automatic gain control corresponding to two signal levels of maximum disparity is provided. In an embodiment described transmission is at 4 levels with a centre «zero». Certain groups from an array of four digits giving large disparities are excluded from the coding table used and the description specifies that each group should include at least one digits of maximum disparity, i.e. 0 or 3 somewhere in the word. Words having the first two digits identical and the second two different are also excluded from the table leaving one array of zero net disparity and another of +/-1 disparity which are channelled respectively into matrices 1, 2, the latter being controlled by bistable circuit 3 so that alternate outputs have + 1, – 1 disparity. At the receiver the quaternary signal passes to decode matrix 5 reconstituting the original signal. Amplifier 4 has A.G.C. corresponding to digits 0, 3 and timing is effected by a local clock pulse generator 6 synchronized by detector circuits 7. Reception of excluded words is identified by an error detector and if there is a succession of these it is assumed that an «out of frame» condition exists hence a signal is passed to a unit 9 to restore correct operation. In another embodiment, Fig. 2 (not shown), the first digit of each quaternary word is a 0 or 3, four separate coding matrices being employed controlled so that D.C. component is zero and the 1.f. component is small. Bistable circuit (16) controls three circuits to ensure that when a disparity has accumulated, the next word has opposite disparity. Alternatively each matrix (12-14) may provide words of alternate disparity. An error detector responds to non- arrival of alternate 0s and 3s and gives an «out of frame» signal.

GB680072A
1971-12-08
1973-02-14
Digital data transmission systems and apparatus therefore

Expired

GB1371615A
(en)

Priority Applications (1)

Application Number
Priority Date
Filing Date
Title

GB680072A

GB1371615A
(en)

1971-12-08
1973-02-14
Digital data transmission systems and apparatus therefore

Applications Claiming Priority (3)

Application Number
Priority Date
Filing Date
Title

GB5828870A

GB1371614A
(en)

1971-12-08
1971-12-08
Digital data transmission systems and apparatus therefore

GB680072A

GB1371615A
(en)

1971-12-08
1973-02-14
Digital data transmission systems and apparatus therefore

GB830772

1973-02-14

Publications (1)

Publication Number
Publication Date

GB1371615A
true

GB1371615A
(en)

1974-10-23

Family
ID=27254895
Family Applications (1)

Application Number
Title
Priority Date
Filing Date

GB680072A
Expired

GB1371615A
(en)

1971-12-08
1973-02-14
Digital data transmission systems and apparatus therefore

Country Status (1)

Country
Link

GB
(1)

GB1371615A
(en)

1973

1973-02-14
GB
GB680072A
patent/GB1371615A/en
not_active
Expired

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Legal Events

Date
Code
Title
Description

1975-03-05
PS
Patent sealed

1979-10-24
PCNP
Patent ceased through non-payment of renewal fee

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