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EP0337762A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Communication system equipped with an AC coupling receiver circuit

Assignee: Furukawa Electric Co Ltd
•
Filing: 1989-04-12
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Granted: —
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Expires: 2009-04-12
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Abstract

Abstract An AC coupling receiver circuit for use in a communication system comprises a comparator(1) connected to transmission lines forming a twisted pair wire, through AC coupling capacitors(C1,C2),and a non-linear element(N)connected between the transmission lines at a position close to the comparator with respect to the capacitors. When positive and negative pulses are respectively applied to the transmission lines, the voltages of the transmission lines are respectively increased and decreased to bring the non-linear element to a substantially cut-off state, thus causing the comparator output to be inverted. As the positive and negative pulses decay, the comparator output is again inverted, thus effecting signal transmission. During the application of pulses, the change stored in the capacitors is quickly discharged through the non-linear element, whereby fluctuation of the received threshold voltage resulting from the stored charge can be eliminated even if pulse inputs are continuous. A high-reliability communication system can be realized by incorporating circuits which enable signal transmission even in the event of a short circuit or disconnection of the transmission lines.

Inventors

  • 👤 Takamichi Ichie

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-06 12:43
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/0264; H04L25/0292; H04L25/0272

Claims Analysis

Total Claims: 11
Claim 1
Independent Claim 88 words
A communication system including a pair of transmission lines as a balanced transmission line, and at least one transmitter circuit and at least one AC coupling receiver circuit both connected to the transmission lines, said AC coupling receiver circuit comprising: AC coupling capacitors connected to said pair of transmission lines, respectively; voltage comparator means connected to said pair of transmission lines through said AC coupling capacitors; and a non-linear element connected between said pair of transmission lines at a position between said capacitors and said voltage comparator means.
Claim 2
Dependent Claim 88 words
A communication system including a pair of transmission lines as a balanced transmission line, and at least one transmitter circuit and at least one AC coupling receiver circuit both connected to the transmission lines, said AC coupling receiver circuit comprising: AC coupling capacitors connected to said pair of transmission lines, respectively; voltage comparator means connected to said pair of transmission lines through said AC coupling capacitors; and a non-linear element connected between said pair of transmission lines at a position between said capacitors and said voltage comparator means.
Claim 3
Dependent Claim 16 words
The communication system according to claim 1, wherein said non-linear element comprises at least one diode.
Claim 4
Dependent Claim 17 words
The communication system according to claim 1, wherein said non-linear element comprises at least one Zener diode.
Claim 5
Dependent Claim 23 words
The communication system according to claim 1,2 or 3 wherein said voltage comparator means of said AC coupling receiver circuit comprises a comparator.
Claim 6
Dependent Claim 98 words
The communication system according to any preceding claim further comprising short-circuit detection means for detecting a short circuit occurring between said pair of transmission lines, and a bias circuit for changing a bias condition of said pair of transmission lines when said short-circuit detection means detects a short circuit, and wherein said AC coupling receiver circuit includes input potential fixing means for fixing the voltage of a transmission line-side portion of the AC coupling capacitor connected to the transmission line whose bias condition is changed, at a predetermined potential when said short-circuit detection means detects a short circuit.
Claim 7
Dependent Claim 71 words
The communication system according to any preceding claim further comprising impedance altering means arranged at input sides of said AC coupling capacitors, respectively, for altering impedances of the input sides of said AC coupling capacitors, and wherein when one of said pair of transmission lines is opened, said impedance altering means brings the input side of the AC coupling capacitor corresponding to the open transmission line to a low impedance state.
Claim 8
Dependent Claim 16 words
The communication system according to claim 6, wherein said impedance altering means comprises a switch circuit.
Claim 9
Dependent Claim 24 words
The communication system according to claim 6, wherein said impedance altering means comprises a series circuit including a switch circuit and a second capacitor.
Claim 10
Dependent Claim 17 words
The communication system according to claim 6, wherein said impedance altering means comprises an emitter follower circuit.
Claim 11
Dependent Claim 27 words
The communication system according to claim 9 , further comprising an element inserted at a base side of said emitter follower circuit, for causing a voltage drop.

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