Patent US3882330A successfully refreshed from Google Patents.
US3882330A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit arrangements
Assignee: Telent Technologies Services Ltd
•
Filing: 1973-04-11
•
Granted: 1975-05-06
•
Expires: 1993-04-11
Abstract
Abstract A variety of linear variable gain elements are described for use in adaptive equalisers, the elements comprising an integrator for controlling the conductance of a field-effect transistor connected in the output thereof in dependence upon a signal/error voltage applied to the integrator, and a voltage source, the voltage of which is variable in dependence upon an applied electrical signal connected to the field-effect transistor and to a further impedance, the outputs from each of which is selectively combined to afford the required output.
Inventors
- 👤 Robert Keith Portway Galpin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:21
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/02; H04B3/04; H04B3/14; H04B3/142
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
262 words
A variable gain circuit arrangement for use in or with an adaptive equaliser comprises integrator means having an input for the application thereto of an applied electrical signal and an output, field effect transistor means connected in the output of said integrator means, a constant voltage source connected directly to the junction of the field effect transistor means and the electrical impedance, and combining means for selectively combining outputs from the field effect traNsistor means and electrical impedance to afford a required output, modulator means to which the signal is applied, the output of the modulator means being fed to the integrator means, the output of the modulator means being applied to the integrator means via a charge resistance, the modulator means taking the form of a balanced modulator which is operated in dependence upon the output of the voltage source and a derived error signal, and the balanced modulator comprising differential amplifier means having two inputs one of which is earthed and an output, first resistor means connected in series with the other of said inputs and to the output of the voltage source, second resistor means connected between the output of the differential amplifier means and the other input, second field effect transistor means for applying the output of said differential amplifier means to the charge resistance in dependence upon the polarity of an error signal and third field effect transistor means for applying the output of the voltage source to the charge resistance in dependence upon the inverse of the polarity applied to said second field effect transistor means.
Claim 2
Dependent Claim
262 words
A variable gain circuit arrangement for use in or with an adaptive equaliser comprises integrator means having an input for the application thereto of an applied electrical signal and an output, field effect transistor means connected in the output of said integrator means, a constant voltage source connected directly to the junction of the field effect transistor means and the electrical impedance, and combining means for selectively combining outputs from the field effect traNsistor means and electrical impedance to afford a required output, modulator means to which the signal is applied, the output of the modulator means being fed to the integrator means, the output of the modulator means being applied to the integrator means via a charge resistance, the modulator means taking the form of a balanced modulator which is operated in dependence upon the output of the voltage source and a derived error signal, and the balanced modulator comprising differential amplifier means having two inputs one of which is earthed and an output, first resistor means connected in series with the other of said inputs and to the output of the voltage source, second resistor means connected between the output of the differential amplifier means and the other input, second field effect transistor means for applying the output of said differential amplifier means to the charge resistance in dependence upon the polarity of an error signal and third field effect transistor means for applying the output of the voltage source to the charge resistance in dependence upon the inverse of the polarity applied to said second field effect transistor means.
Claim 3
Dependent Claim
223 words
A variable gain circuit arrangement for use in or with an adaptive equaliser comprises integrator means having an input for the application thereto of an applied electrical signal and an output, field effect transistor means connected in the output of said integrator means, a constant voltage source connected directly to the junction of the field effect transistor means and the electrical impedance, and combining means for selectively combining outputs from the field effect transistor means and electrical impedance to afford a required output, modulator means to which the signal is applied, the output of the modulator means being fed to the integrator means, the output of the modulator means being applied to the integrator means via a charge resistance, the modulator means taking the form of a balanced modulator which is operated in dependence upon the output of the voltage source and a derived error signal, and in which the balanced modulator comprises differential amplifier means having two inputs and an output, first and second resistor means connected respectively between one of said inputs and the output of the voltage source, third resistor means connected between the output of the differential amplifier means and one of said inputs and second field effect transistor means for causing the other of said inputs to be earthed in dependence upon the polarity of an error signal.
Claim 4
Dependent Claim
223 words
A variable gain circuit arrangement for use in or with an adaptive equaliser comprises integrator means having an input for the application thereto of an applied electrical signal and an output, field effect transistor means connected in the output of said integrator means, a constant voltage source connected directly to the junction of the field effect transistor means and the electrical impedance, and combining means for selectively combining outputs from the field effect transistor means and electrical impedance to afford a required output, modulator means to which the signal is applied, the output of the modulator means being fed to the integrator means, the output of the modulator means being applied to the integrator means via a charge resistance, the modulator means taking the form of a balanced modulator which is operated in dependence upon the output of the voltage source and a derived error signal, and in which the balanced modulator comprises differential amplifier means having two inputs and an output, first and second resistor means connected respectively between one of said inputs and the output of the voltage source, third resistor means connected between the output of the differential amplifier means and one of said inputs and second field effect transistor means for causing the other of said inputs to be earthed in dependence upon the polarity of an error signal.
Claim 5
Dependent Claim
177 words
A variable gain circuit arrangement for use in or with an adaptive equaliser comprises integrator means having an input for the application thereto of an applied electrical signal and an output, field effect transistor means connected in the output of said integrator means, a constant voltage source connected directly to the junction of the field effect transistor means and the electrical impedance, and combining means for selectively combining outputs from the field effect transistor means and electrical impedance to afford a required output, modulator means to which the signal is applied, the output of the modulator means being fed to the integrator means, the output of the modulator means being applied to the integrator means via a charge resistance, and in which the modulator means is of unbalanced form, and in which the integrator means comprises differential amplifier means having two inputs and an output, the charge resistance being connected between the output of the differential amplifier means and the said one input, the other of said inputs being connected to a tap of the electrical impedance.
Claim 6
Dependent Claim
177 words
A variable gain circuit arrangement for use in or with an adaptive equaliser comprises integrator means having an input for the application thereto of an applied electrical signal and an output, field effect transistor means connected in the output of said integrator means, a constant voltage source connected directly to the junction of the field effect transistor means and the electrical impedance, and combining means for selectively combining outputs from the field effect transistor means and electrical impedance to afford a required output, modulator means to which the signal is applied, the output of the modulator means being fed to the integrator means, the output of the modulator means being applied to the integrator means via a charge resistance, and in which the modulator means is of unbalanced form, and in which the integrator means comprises differential amplifier means having two inputs and an output, the charge resistance being connected between the output of the differential amplifier means and the said one input, the other of said inputs being connected to a tap of the electrical impedance.
Claim 7
Dependent Claim
68 words
An arrangement as claimed in claim 3, in which the modulator means comprises second field effect transistor means for connecting the output of the voltage source to the charge resistance in dependence upon the polarity of an error signal and third effect transistor means for connecting the charge resistance to earth in dependence upon the inverse of the polarity applied to the said second field effect transistor means.
Claim 8
Dependent Claim
110 words
An arrangement as claimed in claim 3, in which the modulator means comprises second field effect transistor means for connecting the output of the voltage source to the input of the integrator means, and third field effect transistor means for connecting the input of the integrator means to earth, the second and third field effect transistor means being operated in dependence upon the magnitude and polarity of an error signal in combination with a signal dependent upon the threshold voltage of said transistor means, the arrangement being such that the resistance of the second and third transistor means affords the charge resistance connected in the input of the integrator means.
Claim 9
Dependent Claim
138 words
An arrangement as claimed in claim 3, in which the modulator means comprises differential amplifier means having two inputs and an output, first resistor means connected in series with one of said inputs, second resistor means connected between the output of the differential amplifier means and the said one input, the other input of said differential amplifier means being connected to a further tap of the electrical impedance, second field effect transistor means for applying an error signal to the free end of said first resistor means in dependence upon the polarity of the output of the voltage source, and third field effect transistor means for applying the inverse of said error signal to the said free end of the first resistor means in dependence upon the inverse of the polarity of the output of the voltage source.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-05 | 1978-11-04 | 1979-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-05 | 1982-11-04 | 1983-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-05 | 1986-11-04 | 1987-05-06 | $7700.00 | Window Closed / Lapsed |