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Patent US3568179A successfully refreshed from Google Patents.
US3568179A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Analogue-to-digital converter
Assignee: General Electric Co
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Filing: 1967-09-20
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Granted: 1971-03-02
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Expires: 1987-09-20
Abstract
Abstract A continuously tracking analogue to digital converter including a switching comparison amplifier, a pulse source, a reversible binary counter, and a gating circuit which allows pulses to be applied to the counter only under certain conditions of current imbalance at the amplifier. A negative analogue signal is balanced at the amplifier by a positive D to A converter current and by a deadband current, the polarity of which is changed by the pulse source. The D to A current magnitude is a function of the counter contents and of the supply voltage for the D to A converter. The deadband current is a function of the supply voltage and of the state of a bistable multivibrator connected to the pulse source. When only slight current imbalance exists at the amplifier, the amplifier is continuously switched by the changing deadband current, a condition which inhibits the application of pulses to the counter.
Inventors
- 👤 John O Lampkin Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:55
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/50
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
275 words
An analogue to digital converter for converting an analogue signal having a first polarity and provided by an analogue sensor to its digital equivalent, said converter including: a. a reversible digital counter having direction-controlling input terminals and a count-changing pulse input terminal; b. pulse providing means connected to the direction-controlling input terminals of said counter for alternately enabling said counter to count in a forward direction and in a reverse direction; c. a source of balancing current of a second polarity including; 1. a digital to analogue converter connected to the output of said counter for producing an analogue current proportional to the count in said counter, and 2. a deadband current source connected to said pulse providing means for producing a second polarity current while said counter is enabled to count in a forward direction and a first polarity current while said counter is enabled to count in a reverse direction; d. a comparison amplifier having inputs from the analogue sensor and said source of balancing current, said amplifier producing a first output signal when its total analogue input is of a first polarity and a second output signal when its total analogue input is of a second polarity; and e. a gating means having inputs from said comparison amplifier and said pulse providing means and an output to the countchanging pulse input terminal of said counter, said gating means providing count-changing pulses when said counter is enabled to count in a forward direction and said amplifier is producing the first output signal or when said counter is enabled to count in a reverse direction and said amplifier is producing the second output signal.
Claim 2
Dependent Claim
275 words
An analogue to digital converter for converting an analogue signal having a first polarity and provided by an analogue sensor to its digital equivalent, said converter including: a. a reversible digital counter having direction-controlling input terminals and a count-changing pulse input terminal; b. pulse providing means connected to the direction-controlling input terminals of said counter for alternately enabling said counter to count in a forward direction and in a reverse direction; c. a source of balancing current of a second polarity including; 1. a digital to analogue converter connected to the output of said counter for producing an analogue current proportional to the count in said counter, and 2. a deadband current source connected to said pulse providing means for producing a second polarity current while said counter is enabled to count in a forward direction and a first polarity current while said counter is enabled to count in a reverse direction; d. a comparison amplifier having inputs from the analogue sensor and said source of balancing current, said amplifier producing a first output signal when its total analogue input is of a first polarity and a second output signal when its total analogue input is of a second polarity; and e. a gating means having inputs from said comparison amplifier and said pulse providing means and an output to the countchanging pulse input terminal of said counter, said gating means providing count-changing pulses when said counter is enabled to count in a forward direction and said amplifier is producing the first output signal or when said counter is enabled to count in a reverse direction and said amplifier is producing the second output signal.
Claim 3
Dependent Claim
166 words
a deadband current source connected to said pulse providing means for producing a second polarity current while said counter is enabled to count in a forward direction and a first polarity current while said counter is enabled to count in a reverse direction; d. a comparison amplifier having inputs from the analogue sensor and said source of balancing current, said amplifier producing a first output signal when its total analogue input is of a first polarity and a second output signal when its total analogue input is of a second polarity; and e. a gating means having inputs from said comparison amplifier and said pulse providing means and an output to the count-changing pulse input terminal of said counter, said gating means providing count-changing pulses when said counter is enabled to count in a forward direction and said amplifier is producing the first output signal or when said counter is enabled to count in a reverse direction and said amplifier is producing the second output signal.
Claim 4
Dependent Claim
166 words
a deadband current source connected to said pulse providing means for producing a second polarity current while said counter is enabled to count in a forward direction and a first polarity current while said counter is enabled to count in a reverse direction; d. a comparison amplifier having inputs from the analogue sensor and said source of balancing current, said amplifier producing a first output signal when its total analogue input is of a first polarity and a second output signal when its total analogue input is of a second polarity; and e. a gating means having inputs from said comparison amplifier and said pulse providing means and an output to the count-changing pulse input terminal of said counter, said gating means providing count-changing pulses when said counter is enabled to count in a forward direction and said amplifier is producing the first output signal or when said counter is enabled to count in a reverse direction and said amplifier is producing the second output signal.
Claim 5
Dependent Claim
84 words
An analogue to digital converter as recited in claim 1 wherein the digital to analogue converter in said source of balancing current includes parallel branches connected between an input to said comparison amplifier and a source of voltage at the second polarity, each of said branches including a switching circuit connected to and controlled by a bit in said reversible counter and a serially connected resistor having a magnitude inversely proportional to the weight of the bit to which the switching circuit is connected.
Claim 6
Dependent Claim
108 words
An analogue to digital converter as recited in claim 2 wherein said deadband current source includes: a. a first resistor connected between said source of voltage at the second polarity and an input to said comparison amplifier; b. a second resistor connected at one end to an input to said comparison amplifier to apply current thereto in subtractive relation to the current supplied through said first resistor; and c. a switching circuit for selectively connecting said second resistor to said voltage source, said switching circuit being repetitively energized by said pulse-providing means in synchronism with changes in the direction in which said reversible counter is enabled to count.
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) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |