Patent US3930252A successfully refreshed from Google Patents.
US3930252A
Expired / Lapsed
US
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Bipolar dual-slope analog-to-digital converter
Assignee: SYCON Corp A CORP OF DE
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Filing: 1973-12-26
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Granted: 1975-12-30
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Expires: 1993-12-26
Abstract
Abstract A bipolar analog-to-digital converter system is disclosed which is particularly suited as a digital volt meter or digital multimeter. The system includes an integrator and a solid state switching circuit alternately connecting to and is directly proportional to the integrator either an analog input signal of unknown magnitude and of either polarity or an analog reference signal of preselected magnitude and fixed polarity. A pulse generator supplies pulses at a constant rate to a digital counter. Provision is included for resetting the counter to a predetermined first count and for causing the switching means to apply the input signal to the integrator so that its output signal increases linearly from a reset value while the counter advances from the first count to a predetermined second count. Circuitry responsive to the second count causes the switching circuit to apply the reference signal to the integrator so that its output signal decreases linearly toward the reset value while the counter advances from the second count toward a predetermined third count. The reset value is reached prior to the third count for an analog input signal of a first polarity but after the third count if of an opposite polarity. A digital display and associated digital circuitry cause display of a decimal number corresponding to the complement of the count in the counter when the output signal from the integrator reaches the reset value prior to the third count but are responsive to the counter reaching the third count for causing a display of a decimal number corresponding to the true count in the counter when the integrator output signal then reaches the reset value. The decimal number displayed thus digitally corresponds to the true magnitude of the analog input signal.
Inventors
- 👤 Robert C Storar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:15
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/50; H03M1/52
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
450 words
A bipolar dual-slope analog-to-digital converter system for converting an analog input signal of unknown polarity to a decimal number which is directly proportional to said analog input signal, said system comprising: a. an integrator for providing an output signal which is proportional to the time integral of the magnitude with respect to a single analog reference of preselected magnitude and polarity of signal applied to the input thereof; b. solid state switching means for alternately connecting to the input of said integrator either a first signal corresponding to an analog input signal of unknown magnitude and of either positive or negative polarity or a second signal constituting said single analog reference; c. a pulse generator for supplying pulses at a substantially constant pulse repetition rate; d. a digital counter for counting said pulses; e. automatic means for effecting determination of the polarity of said analog input signal without polarity sensing of said analog input signal and for effecting display of a decimal number which is directly proportional to said analog input signal regardless of the polarity thereof, said automatic means comprising: 1. means for resetting said counter to a predetermined first count and for causing said switching means to apply one of said first and second signals to the input of said integrator whereby the output signal from said integrator increases linearly with respect to time from a reset value while said counter advances from said first count to a predetermined second count; 2. means responsive to said second count for causing said switching means to apply the other of said first and second signals to the input of said integrator whereby the output signal from said integrator decreases linearly with respect to time toward said reset value while said counter advances from said second count toward a predetermined third count, said reset value being reached prior to said third count if said first signal is of a first polarity and said reset value being reached after said third count if said first signal is of opposite polarity; 3. digital display means; 4. complement count means for causing said digital display means to display a decimal number corresponding to the complement of the count in said counter upon the output signal from said integrator reaching said reset value prior to said third count; and 5. true count means responsive to said counter reaching said third count for causing said digital display means to display a decimal number corresponding to the true count in said counter upon the output signal from said integrator reaching said reset value, whereby the decimal number displayed by said display means digitally represents the true magnitude of said analog input signal regardless of the polarity thereof.
Claim 2
Dependent Claim
450 words
A bipolar dual-slope analog-to-digital converter system for converting an analog input signal of unknown polarity to a decimal number which is directly proportional to said analog input signal, said system comprising: a. an integrator for providing an output signal which is proportional to the time integral of the magnitude with respect to a single analog reference of preselected magnitude and polarity of signal applied to the input thereof; b. solid state switching means for alternately connecting to the input of said integrator either a first signal corresponding to an analog input signal of unknown magnitude and of either positive or negative polarity or a second signal constituting said single analog reference; c. a pulse generator for supplying pulses at a substantially constant pulse repetition rate; d. a digital counter for counting said pulses; e. automatic means for effecting determination of the polarity of said analog input signal without polarity sensing of said analog input signal and for effecting display of a decimal number which is directly proportional to said analog input signal regardless of the polarity thereof, said automatic means comprising: 1. means for resetting said counter to a predetermined first count and for causing said switching means to apply one of said first and second signals to the input of said integrator whereby the output signal from said integrator increases linearly with respect to time from a reset value while said counter advances from said first count to a predetermined second count; 2. means responsive to said second count for causing said switching means to apply the other of said first and second signals to the input of said integrator whereby the output signal from said integrator decreases linearly with respect to time toward said reset value while said counter advances from said second count toward a predetermined third count, said reset value being reached prior to said third count if said first signal is of a first polarity and said reset value being reached after said third count if said first signal is of opposite polarity; 3. digital display means; 4. complement count means for causing said digital display means to display a decimal number corresponding to the complement of the count in said counter upon the output signal from said integrator reaching said reset value prior to said third count; and 5. true count means responsive to said counter reaching said third count for causing said digital display means to display a decimal number corresponding to the true count in said counter upon the output signal from said integrator reaching said reset value, whereby the decimal number displayed by said display means digitally represents the true magnitude of said analog input signal regardless of the polarity thereof.
Claim 3
Dependent Claim
84 words
means responsive to said second count for causing switching means to apply said second signal to the input of said integrator whereby the output signal from said integrator decreases linearly with respect to time toward said reset value while said counter advances from said second count toward a predetermined third count, said reset value being reached prior to said third count for a first polarity analog input signal said reset value being reached after said third count for an opposite polarity analog input signal;
Claim 4
Dependent Claim
84 words
means responsive to said second count for causing switching means to apply said second signal to the input of said integrator whereby the output signal from said integrator decreases linearly with respect to time toward said reset value while said counter advances from said second count toward a predetermined third count, said reset value being reached prior to said third count for a first polarity analog input signal said reset value being reached after said third count for an opposite polarity analog input signal;
Claim 5
Dependent Claim
94 words
means responsive to said second count for causing said switching means to apply the other of said first and second signals to the input of said integrator whereby the output signal from said integrator decreases linearly with respect to time toward said reset value while said counter advances from said second count toward a predetermined third count, said reset value being reached prior to said third count if said first signal is of a first polarity and said reset value being reached after said third count if said first signal is of opposite polarity;
Claim 6
Dependent Claim
94 words
means responsive to said second count for causing said switching means to apply the other of said first and second signals to the input of said integrator whereby the output signal from said integrator decreases linearly with respect to time toward said reset value while said counter advances from said second count toward a predetermined third count, said reset value being reached prior to said third count if said first signal is of a first polarity and said reset value being reached after said third count if said first signal is of opposite polarity;
Claim 7
Dependent Claim
52 words
A bipolar analog-to-digital converter system as set forth in claim 1 further comprising means for maintaining said reset value of the integrator output signal substantially precisely in a steady state condition following decrease of the integrator output signal to said reset value until said counter is reset to said predetermined first count.
Claim 8
Dependent Claim
32 words
A bipolar analog-to-digital converter system as set forth in claim 1 wherein said means for resetting said counter comprises pulse generating means for supplying reset pulses to said solid state switching means.
Claim 9
Dependent Claim
3 words
digital display means;
Claim 10
Dependent Claim
3 words
digital display means;
Claim 11
Dependent Claim
4 words
digital display means; and
Claim 12
Dependent Claim
4 words
digital display means; and
Claim 13
Dependent Claim
41 words
complement count means for causing said digital display means to display a decimal number corresponding to the complement of the count in said counter upon the output signal from said integrator reaching said reset value prior to said third count; and
Claim 14
Dependent Claim
41 words
complement count means for causing said digital display means to display a decimal number corresponding to the complement of the count in said counter upon the output signal from said integrator reaching said reset value prior to said third count; and
Claim 15
Dependent Claim
46 words
A bipolar analog-to-digital converter system as set forth in claim 1 further comprising overrange detecting means for causing said digital display means to provide overrange indication when said analog input signal is of an overrange magnitude greater than can be represented by said digital display means.
Claim 16
Dependent Claim
123 words
count responsive means including complement count means for causing said digital display to display a decimal number corresponding to the complement of the count in said counter upon the output signal from said integrator reaching said reset value; and true count means for causing said digital display means to display a decimal number corresponding to the true count in said counter upon the output signal from said integral reaching said reset value; and means responsive to said counter reaching said thirD count for disabling said complement count means and enabling said true count means; whereby the decimal number displayed by said display means digitally represents and is directly proprotional to the true magnitude of said analog input signal regardless of the polarity thereof.
Claim 17
Dependent Claim
123 words
count responsive means including complement count means for causing said digital display to display a decimal number corresponding to the complement of the count in said counter upon the output signal from said integrator reaching said reset value; and true count means for causing said digital display means to display a decimal number corresponding to the true count in said counter upon the output signal from said integral reaching said reset value; and means responsive to said counter reaching said thirD count for disabling said complement count means and enabling said true count means; whereby the decimal number displayed by said display means digitally represents and is directly proprotional to the true magnitude of said analog input signal regardless of the polarity thereof.
Claim 18
Dependent Claim
65 words
true count means responsive to said counter reaching said third count for causing said digital display means to display a decimal number corresponding to the true count in said counter upon the output signal from said integrator reaching said reset value, whereby the decimal number displayed by said display means digitally represents the true magnitude of said analog input signal regardless of the polarity thereof.
Claim 19
Dependent Claim
65 words
true count means responsive to said counter reaching said third count for causing said digital display means to display a decimal number corresponding to the true count in said counter upon the output signal from said integrator reaching said reset value, whereby the decimal number displayed by said display means digitally represents the true magnitude of said analog input signal regardless of the polarity thereof.
Claim 20
Dependent Claim
20 words
A bipolar analog-to-digital converter system as set forth in claim 1 wherein said counter is a binary coded decimal counter.
Claim 21
Dependent Claim
31 words
A bipolar analog-to-digital converter system As set forth in claim 5 wherein said true count means comprises latch means for transferring a count in said counter to said digital display means.
Claim 22
Dependent Claim
39 words
A bipolar analog-to-digital converter system as set forth in claim 6 wherein said complement count means comprises nines-complement circuitry interconnected with said latch means for causing transferring of a complemented count in said counter to said digital display means.
Claim 23
Dependent Claim
52 words
A bipolar analog-to-digital converter system as set forth in claim 7 including multiplex means selectively responsive to binary coded signals from either said latch means or said nines-complement circuitry, and means interconnected with said counter and said multiplex means causing selective operation of said multiplex means in response to said third count.
Claim 24
Dependent Claim
52 words
A bipolar analog-to-digital converter system as set forth in claim 1 further comprising polarity detecting means for causing display of a first polarity sign by said digital display means in response to a predetermined count in said counter and an opposite polarity sign in response to another predetermined count in said counter.
Claim 25
Dependent Claim
27 words
A bipolar analog-to-digital converter system as set forth in claim 1 wherein said digital display means comprises a numeric readout having a plurality of electroluminescent numeric indicators.
Claim 26
Dependent Claim
21 words
A bipolar analog-to-digital converter system as set forth in claim 10 wherein said numeric indicators comprise respective multi-segment LED display devices.
Claim 27
Dependent Claim
163 words
A bipolar dual-slope analog-to-digital converter system for converting an analog input signal of unknown polarity to a decimal number which is directly proportional to said analog input signal, said system comprising: a. an integrator for providing an output signal which is proportional to the time integral of the magnitude, with respect to a single analog reference of preselected magnitude and polarity, of a signal applied to the input thereof; b. solid state switching means for alternately connecting to the input of said integrator either a first signal corresponding to an analog input signal of unknown magnitude and of either positive or negative polarity or a second signal constituting said single analog reference; c. a pulse generator for supplying pulses at a substantially constant pulse repetition rate; d. a digital counter for counting said pulses; e. automatic means for effecting the display of a decimal number which is directly proportional to said analog input signal regardless of the polarity thereof, said automatic means comprising:
Claim 28
Dependent Claim
163 words
A bipolar dual-slope analog-to-digital converter system for converting an analog input signal of unknown polarity to a decimal number which is directly proportional to said analog input signal, said system comprising: a. an integrator for providing an output signal which is proportional to the time integral of the magnitude, with respect to a single analog reference of preselected magnitude and polarity, of a signal applied to the input thereof; b. solid state switching means for alternately connecting to the input of said integrator either a first signal corresponding to an analog input signal of unknown magnitude and of either positive or negative polarity or a second signal constituting said single analog reference; c. a pulse generator for supplying pulses at a substantially constant pulse repetition rate; d. a digital counter for counting said pulses; e. automatic means for effecting the display of a decimal number which is directly proportional to said analog input signal regardless of the polarity thereof, said automatic means comprising:
Claim 29
Dependent Claim
65 words
A bipolar analog-to-digital converter system as set forth in claim 12 further comprising: means for detecting said reset value of the integrator output signal; and clamp means for causing said reset value to be maintained substantially precisely in a steady state condition after said reset value is reached following decrease of the integrator output signal until said counter is reset to said predetermined first count.
Claim 30
Dependent Claim
54 words
A bipolar analog-to-digital converter system as set forth in claim 13 wherein: said means for detecting said reset value comprises a voltage comparator connected to the output of said integrator; and said clamp means comprises a feedback circuit including a diode interconnected between an output of said comparator and an input of said integrator.
Claim 31
Dependent Claim
63 words
A bipolar analog-to-digital converter system as set forth in claim 14 wherein: said voltage comparator is connected for providing a pulse waveform output signal upon said integrator output signal reading said reset value, and said feedback circuit includes a damping network for critical damping of the feedback signal provided by said feedback circuitry whereby said pulse waveform output signal constitutes a single pulse.
Claim 32
Dependent Claim
48 words
a bipolar analog-to-digital converter system as set forth in claim 12 wherein said means for resetting said counter comprises pulse generating means interconnected with said switching means and said counter and adapted for periodically supplying reset pulses at a rate much less than said constant pulse repetition rate.
Claim 33
Dependent Claim
42 words
A bipolar analog-to-digital converter system as set forth in claim 12 further comprising overrange detecting means for providing indication of said analog input signal of an overrange magnitude greater than a preselected value which can be represented by said digital display means.
Claim 34
Dependent Claim
36 words
A bipolar analog-to-digital converter system as set forth in claim 17 wherein said overrange detecting means causes blanking of digits of said digital display means thereby to indicate that said input signal is of overrange magnitude.
Claim 35
Dependent Claim
105 words
A bipolar analog-to-digital converter system as set forth in claim 18 wherein said overrange detecting means comprises: a flip-flop having a first state permitting display by said digital display means and a second state causing said blanking of digits; and means interconnected with said counter for causing said flip-flop to assume said first state in response to a predetermined fourth count in said counter and to assume said second state in response to a predetermined fifth count in said counter, said blanking of digits occurring if the reset value of said integrator is not reached after said fourth count and prior to said fifth count.
Claim 36
Dependent Claim
34 words
A bipolar analog-to-digital converter system as set forth in claim 12 wherein said digital counter comprises a binary coded decimal counter having a plurality of decades corresponding to respective digits of said decimal number.
Claim 37
Dependent Claim
63 words
A bipolar analog-to-digital converter system as set forth in claim 20 wherein said count-responsive means comprises a plurality of latch circuits corresponding to respective ones of said decades, said latch circuits being concomitantly operable upon the output signal from said integrator reaching said reset value to transfer the count in said counter to either said complement count means or said true count means.
Claim 38
Dependent Claim
30 words
A bipolar analog-to-digital converter system as set forth in claim 21 wherein said complement count means comprises a plurality of nines-complement circuits interconnected with respective ones of said latch circuits.
Claim 39
Dependent Claim
72 words
A bipolar analog-to-digital converter system as set forth in claim 22 wherein said means responsive to Said counter reaching said third count comprises: a plurality of multiplex circuits having inputs interconnected with respective ones of said latch circuits and said nines-complement circuits and outputs interconnected with said digital display means; and multiplex control means interconnected with said counter for causing concomitant operation of said multiplex circuits in response to said third count.
Claim 40
Dependent Claim
92 words
A bipolar analog-to-digital converter system as set forth in claim 12 further comprising polarity detecting means comprising: a flip-flop having a first state causing display by said digital display means of a first polarity sign and a second state causing display by said digital display means of an opposite polarity sign; and means interconnected with said counter for causing said flip-flop to assume said first state in response to a predetermined first count in said counter and to assume said second state in response to said predetermined third count in said counter.
Claim 41
Dependent Claim
67 words
A bipolar analog-to-digital converter system as set forth in claim 12 wherein said integrator comprises: an operational amplifier having inverting and non-inverting inputs, said first and second signals being supplied alternatively to said inverting input; a capacitor connected in a circuit between the output of said operational amplifier and the inverting input thereof; and means for supplying to said non-inverting input a reference potential of preselected magnitude.
Claim 42
Dependent Claim
42 words
A bipolar analog-to-digital converter system as set forth in claim 25 wherein said preselected magnitude of the reference potential is greater than said first signal for any value of said analog input signal which is to be represented by said display means.
Claim 43
Dependent Claim
112 words
A bipolar analog-to-digital converter system as set forth in claim 26 wherein said second signal constituting an analog reference signal has a magnitude Vr, said reference potential has a magnitude KVR where K is a constant, said first signal has a magnitude Ei, K being chosen so that Ei has an absolute value less than KVr within the operating range of Ei and wherein said integrator integrates in a positive sense current proportional to KVR - Ei when said first signal is applied to said inverting input and said integrator integrates in a negative sense current proportional to VR (1 - K) when said second signal is applied to said inverting input.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-29 | 1979-06-30 | 1979-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-29 | 1983-06-30 | 1983-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-29 | 1987-06-30 | 1987-12-30 | $7700.00 | Window Closed / Lapsed |