US3857048A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic equalizing amplifiers for the transmission of digital signals
Assignee: Lignes Telegraphiques et Telephoniques LTT SA
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Filing: 1973-10-15
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Granted: 1974-12-24
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Expires: 1993-10-15
Abstract
Abstract A device for equalizing the electrically equivalent lengths of line sections between successive amplifiers in a digital signal transmission system. It comprises the cascade combination of a plurality of amplifiers, fixed impedance networks and adjustable impedance networks controlled by variable resistances, and includes a feedback path delivering a current to said variable resistances, said current varying according to the average peak amplitude of the output signal of said device. The attenuation provided by the adjustable networks is higher when the equivalent length of the preceding line section is shorter. Means are provided for adjusting the variation ranges of the variable resistors.
Inventors
- 👤 Laage De Meux P De
- 👤 C Gourdon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:57
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03019
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
132 words
An equalizing amplifier for digital signals, comprising at least two partial amplifiers cascade-connected with at least two variable compensating linear networks, the attenuation and frequency distortion of which are controlled by a direct-current control signal proportional to the difference between the means value of the peak amplitude of the output signal of said equalizing amplifier and a fixed reference voltage, in which each one of said networks includes a variable resistor the value of which is controlled by said control signal, said equalizing amplifier being further characterized in that said control signal is applied to at least part of said networks through at least one semiconductor diode threshold device in the direct conduction direction having its threshold level individually selected for each one of the networks of said part of said networks.
Claim 2
Dependent Claim
132 words
An equalizing amplifier for digital signals, comprising at least two partial amplifiers cascade-connected with at least two variable compensating linear networks, the attenuation and frequency distortion of which are controlled by a direct-current control signal proportional to the difference between the means value of the peak amplitude of the output signal of said equalizing amplifier and a fixed reference voltage, in which each one of said networks includes a variable resistor the value of which is controlled by said control signal, said equalizing amplifier being further characterized in that said control signal is applied to at least part of said networks through at least one semiconductor diode threshold device in the direct conduction direction having its threshold level individually selected for each one of the networks of said part of said networks.
Claim 3
Dependent Claim
41 words
An equalizing amplifier as claimed in claim 1, in which said variable resistors each consist of an assembly of two series connected semiconductor diodes in direct conduction direction and through which there flows a control current proportional to said control signal.
Claim 4
Dependent Claim
24 words
An equalizing amplifier as claimed in claim 2, in which a decoupling capacitor is in parallel connection with the series assembly of said diodes.
Claim 5
Dependent Claim
20 words
An equalizing ampliFier as claimed in claim 1, in which said diodes are individually series connected to a fixed resistor.
Claim 6
Dependent Claim
20 words
An equalizing amplifier as claimed in claim 1, in which said fixed reference voltage is taken across a Zener diode.
Claim 7
Dependent Claim
23 words
An equalizing amplifier as claimed in claim 1, in which at least part of said linear networks are made of capacitors and resistors.
Claim 8
Dependent Claim
42 words
An equalizing amplifier as claimed in claim 1, in which said control signl is obtained from a circuit including a peak detector charging a capacitor, the voltage across which is amplified by a direct current amplifier whose output delivers said control signal.
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) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |