US3683367A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital automatic gain control
Assignee: CBHBC Corp LLC
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Filing: 1970-02-12
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Granted: 1972-08-08
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Expires: 1990-02-12
Abstract
Abstract An analog to digital signal converting amplifier with automatic gain control. Input analog signal levels are converted to digital form after passing through a variable gain amplifier device. The digital signals are reconverted to analog form and compared to the input analog levels to produce an error signal which is averaged and used to control the gain of the amplifier device. The analog to digital converted produces a maximum output data indication even through the input level may be excessive. A nonzero difference signal is generated even if the digital output is zero.
Inventors
- 👤 Kenneth E Monroe
- 👤 Samuel T Harmon Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:34
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3005; H03M; H03M1/00; H03M1/12; H03M1/18
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
340 words
An automatic gain control circuit for a data responsive amplifier comprising: variable gain input amplifier means responsive to an analog data signal of variable amplitude to produce a variable amplitude analog output signal the amplitudE of which varies between substantially zero and A where A is a finite maximum output level; analog-to-digital output converter means having an input connected to receive the analog output of the variable gain amplifier and a plurality of output terminals, the analog-to-digital converter being operative to produce on said output terminals the digital equivalent of the amplitude of the signal applied to said input terminal up to a finite maximum output signal level B where B is less than A; feedback means connected between the variable gain input amplifier and said output terminals and being operative to vary the gain of said input amplifier and including a digital-to-analog converter having a plurality of input terminals connected to the output terminals of the analog-to-digital converter and further having an output terminal on which an analog signal is produced which is the mathematical equivalent of the signal on said input terminals; a differential amplifier having two input terminals connected to receive the analog output of the input amplifier on one terminal and the analog output of the digital-to-analog converter on another terminal and to compare the signals on said terminals and to produce an error signal related to the difference therebetween; multiplier means connected to receive the output of the digital-to-analog converter as well as the error signal output of the differential amplifier means and being operative to produce a second error signal which varies in amplitude between C and B where C is a finite minimum amplitude signal greater than zero but less than A; integrator means connected to receive the second error signal and to integrate the signal with time to produce a slowly-increasing error signal component, said error signal component being connected to the input amplifier to vary the gain thereof in such a direction as to reduce the feedback error signal toward zero.
Claim 2
Dependent Claim
340 words
An automatic gain control circuit for a data responsive amplifier comprising: variable gain input amplifier means responsive to an analog data signal of variable amplitude to produce a variable amplitude analog output signal the amplitudE of which varies between substantially zero and A where A is a finite maximum output level; analog-to-digital output converter means having an input connected to receive the analog output of the variable gain amplifier and a plurality of output terminals, the analog-to-digital converter being operative to produce on said output terminals the digital equivalent of the amplitude of the signal applied to said input terminal up to a finite maximum output signal level B where B is less than A; feedback means connected between the variable gain input amplifier and said output terminals and being operative to vary the gain of said input amplifier and including a digital-to-analog converter having a plurality of input terminals connected to the output terminals of the analog-to-digital converter and further having an output terminal on which an analog signal is produced which is the mathematical equivalent of the signal on said input terminals; a differential amplifier having two input terminals connected to receive the analog output of the input amplifier on one terminal and the analog output of the digital-to-analog converter on another terminal and to compare the signals on said terminals and to produce an error signal related to the difference therebetween; multiplier means connected to receive the output of the digital-to-analog converter as well as the error signal output of the differential amplifier means and being operative to produce a second error signal which varies in amplitude between C and B where C is a finite minimum amplitude signal greater than zero but less than A; integrator means connected to receive the second error signal and to integrate the signal with time to produce a slowly-increasing error signal component, said error signal component being connected to the input amplifier to vary the gain thereof in such a direction as to reduce the feedback error signal toward zero.
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) | 1975-08-08 | 1976-02-07 | 1976-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-08 | 1980-02-07 | 1980-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-08 | 1984-02-07 | 1984-08-08 | $7700.00 | Window Closed / Lapsed |