US4143239A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal distortion correction circuit in teleprinter equipment
Assignee: US Philips Corp
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Filing: 1977-12-12
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Granted: 1979-03-06
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Expires: 1997-12-12
Abstract
Abstract A distortion correction circuit in teleprinter equipment which transmits messages between a station and a teleprinter apparatus by feeding DC-pulses through a line interconnecting the station and the teleprinter apparatus is disclosed. The line has a capacitance dependent upon the length of the line and a variable impedance element in series with the line path.
Inventors
- 👤 Hans E. Hultman
- 👤 Alexander Strid
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:59
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/12; H04L25/0264; H04L25/028; H04L25/0282
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
122 words
A method of transmitting dc pulses in a teleprinter communication system along a line which has a capacitance depending upon the length of the line and which includes a variable impedance element in series with the line comprising the steps of: producing a current flow during a time interval following the closing of the line path at the beginning of a current pulse; changing the value of the impedance element to a high first value immediately following the commencement of current flow; subsequently rapidly decreasing the value of the impedance element to a low second value so that the line current flowing is kept substantially constant; and maintaining the impedance element at said low second value to the end of the pulse.
Claim 2
Independent Claim
122 words
A method of transmitting dc pulses in a teleprinter communication system along a line which has a capacitance depending upon the length of the line and which includes a variable impedance element in series with the line comprising the steps of: producing a current flow during a time interval following the closing of the line path at the beginning of a current pulse; changing the value of the impedance element to a high first value immediately following the commencement of current flow; subsequently rapidly decreasing the value of the impedance element to a low second value so that the line current flowing is kept substantially constant; and maintaining the impedance element at said low second value to the end of the pulse.
Claim 3
Independent Claim
125 words
A method of transmitting dc pulses in a teleprinter communication system along a line which has a capacitance depending upon the length of the line and which includes a variable impedance element in series with the line comprising the steps of: producing a current flow during a time interval following the closing of the line path at the beginning of a current pulse; changing the value of the impedance element to a high first value immediately following the commencement of current flow; and subsequently rapidly decreasing the value of the impedance element so that the line current flowing as a function of time follows a smooth curve having a finite and equal slope at the beginning of the pulse and the end of the pulse.
Claim 4
Independent Claim
125 words
A method of transmitting dc pulses in a teleprinter communication system along a line which has a capacitance depending upon the length of the line and which includes a variable impedance element in series with the line comprising the steps of: producing a current flow during a time interval following the closing of the line path at the beginning of a current pulse; changing the value of the impedance element to a high first value immediately following the commencement of current flow; and subsequently rapidly decreasing the value of the impedance element so that the line current flowing as a function of time follows a smooth curve having a finite and equal slope at the beginning of the pulse and the end of the pulse.
Claim 5
Dependent Claim
87 words
An arrangement for teleprinter equipment in which dc pulses representing characters are transmitted along a line comprising: switch means in series with the line which generate the dc pulses; and a constant current generator in series with the line including a controllable semiconductive element which functions to limit the current flow in said line, during a time interval immediately following the commencement of current flow, to a predetermined value so that the value of the current flow is kept substantially constant during each of the dc pulses.
Claim 6
Dependent Claim
87 words
An arrangement for teleprinter equipment in which dc pulses representing characters are transmitted along a line comprising: switch means in series with the line which generate the dc pulses; and a constant current generator in series with the line including a controllable semiconductive element which functions to limit the current flow in said line, during a time interval immediately following the commencement of current flow, to a predetermined value so that the value of the current flow is kept substantially constant during each of the dc pulses.
Claim 7
Dependent Claim
32 words
An arrangement as defined in claim 3 wherein said constant current generator comprises first and second terminals, said generator functioning to maintain a substantially zero voltage across said first and second terminals.
Claim 8
Dependent Claim
36 words
An arrangement as defined in claim 4 further comprising variable resistance means functionally connected in series with the line which function to maintain said substantially zero voltage across said first and second terminals of said generator.
Claim 9
Dependent Claim
25 words
An arrangement as defined in claim 5, wherein said controllable semiconductive element functions as a switch which switches between a conducting and a non-conducting state.
Claim 10
Dependent Claim
115 words
An arrangement for teleprinter equipment in which dc pulses representing characters are transmitted along a line comprising: a pulse generator for forming a sequence of rectangular pulses representing binary coded characters in a message; a pulse shaper connected to said pulse generator which converts said pulses to substantially symmetric pulse signals having a finite slope on both the front and rear pulse edges; current regulation means connected to said pulse shaper and controlled by said pulse signals for instantaneously adjusting the current through the line, including a controllable semiconductive element which functions to act as a variable impedance element in the line and as a switch element for generating the dc pulses in the line.
Claim 11
Dependent Claim
115 words
An arrangement for teleprinter equipment in which dc pulses representing characters are transmitted along a line comprising: a pulse generator for forming a sequence of rectangular pulses representing binary coded characters in a message; a pulse shaper connected to said pulse generator which converts said pulses to substantially symmetric pulse signals having a finite slope on both the front and rear pulse edges; current regulation means connected to said pulse shaper and controlled by said pulse signals for instantaneously adjusting the current through the line, including a controllable semiconductive element which functions to act as a variable impedance element in the line and as a switch element for generating the dc pulses in the line.
Claim 12
Dependent Claim
23 words
An arrangement as defined in claim 7 further comprising a low pass filter connected between said pulse shaper and said current regulation means.
Claim 13
Dependent Claim
21 words
An arrangement as defined in claim 7 wherein said low pass filter is an active filter of at least second degree.
Claim 14
Dependent Claim
106 words
In a teleprinter communications system of the type in which dc pulses representing characters in a message transmitted along a line are generated by closing and opening a switch in series with the line, and including a constant current generator in the teleprinter connected in series with the line, the improvement comprising: a controllable semiconductive element in said constant current generator which functions to limit the current flow to a predetermined value equal to the value of the current flow during steady-state operation of the system during a time interval immediately following the commencement of current flow by assuming a high impedance value at that time.
Claim 15
Dependent Claim
106 words
In a teleprinter communications system of the type in which dc pulses representing characters in a message transmitted along a line are generated by closing and opening a switch in series with the line, and including a constant current generator in the teleprinter connected in series with the line, the improvement comprising: a controllable semiconductive element in said constant current generator which functions to limit the current flow to a predetermined value equal to the value of the current flow during steady-state operation of the system during a time interval immediately following the commencement of current flow by assuming a high impedance value at that time.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-03-05 | 1982-09-04 | 1983-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-05 | 1986-09-04 | 1987-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-05 | 1990-09-04 | 1991-03-06 | $7700.00 | Window Closed / Lapsed |