US3691473A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Voltage ratio apparatus with logarithmic output
Assignee: Northeast Electronics Corp
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Filing: 1968-08-19
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Granted: 1972-09-12
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Expires: 1988-08-19
Abstract
Abstract Both an input voltage signal and an adjustable reference voltage signal are compared with an exponential wave for providing, through a logic circuit, an output pulse whose width is proportional to the logarithm, either to the base 10 or to the natural base, of the ratio of the input signal to the reference signal. The output pulse controls a gate supplied with clock pulses for providing a digital output.
Inventors
- 👤 John T Boatwright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:10
CPC Classifications
G; G06; G06G; G06G7/00; G06G7/12; G06G7/24; H; H03; H03M; H03M1/00; H03M1/12; H03M1/50; H03M1/58
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
343 words
Apparatus for providing an output signal having a parameter proportional to the logarithm of the ratio of an input voltage signal to a reference voltage signal comprising in combination: a source of exponentially varying voltage; first means for comparing the voltage from said source with said input voltage signal to provide a first signal manifestation at the instant in time when the absolute values of the last two voltages are equal; second means for comparing the voltage from said source with said reference voltage signal to provide a second Signal manifestation at the instant in time when the absolute values of the last two voltages are equal; and means coupled to said first and second means and responsive to said first and second signal manifestations for providing an output signal having a parameter proportional to the time interval between the occurrence of said two signal manifestations, said first means comprising a first very high gain amplifier circuit whose voltage output is alterable between two extreme limits in response to variation in its input signal above and below a given datum, and means for adding a voltage from said source having positive polarity relative to said datum to an input voltage signal of negative polarity relative to said datum and feeding the sum voltage to said first amplifier circuit to change the output voltage of said first amplifier circuit from one of said limits to the other when said sum voltage passes through said datum; and said second means comprising a second very high gain amplifier circuit whose voltage output is alterable between two extreme limits in response to variation in its input signal above and below a given datum, and means for adding a voltage from said source having positive polarity relative to said datum to a reference voltage signal of negative polarity relative to said datum and feeding the sum voltage to said second amplifier circuit to change the output voltage of said second amplifier circuit from one of said limits to the other when said sum voltage passes through said datum.
Claim 2
Dependent Claim
343 words
Apparatus for providing an output signal having a parameter proportional to the logarithm of the ratio of an input voltage signal to a reference voltage signal comprising in combination: a source of exponentially varying voltage; first means for comparing the voltage from said source with said input voltage signal to provide a first signal manifestation at the instant in time when the absolute values of the last two voltages are equal; second means for comparing the voltage from said source with said reference voltage signal to provide a second Signal manifestation at the instant in time when the absolute values of the last two voltages are equal; and means coupled to said first and second means and responsive to said first and second signal manifestations for providing an output signal having a parameter proportional to the time interval between the occurrence of said two signal manifestations, said first means comprising a first very high gain amplifier circuit whose voltage output is alterable between two extreme limits in response to variation in its input signal above and below a given datum, and means for adding a voltage from said source having positive polarity relative to said datum to an input voltage signal of negative polarity relative to said datum and feeding the sum voltage to said first amplifier circuit to change the output voltage of said first amplifier circuit from one of said limits to the other when said sum voltage passes through said datum; and said second means comprising a second very high gain amplifier circuit whose voltage output is alterable between two extreme limits in response to variation in its input signal above and below a given datum, and means for adding a voltage from said source having positive polarity relative to said datum to a reference voltage signal of negative polarity relative to said datum and feeding the sum voltage to said second amplifier circuit to change the output voltage of said second amplifier circuit from one of said limits to the other when said sum voltage passes through said datum.
Claim 3
Dependent Claim
47 words
Apparatus according to claim 1, wherein said first and second amplifier circuits each consist of an operational amplifier with one operational amplifier providing an output of the same polarity as its input and the other operational amplifier providing an output of inverted polarity relative to its input.
Claim 4
Dependent Claim
243 words
Apparatus for providing an output signal having a parameter proportional to the logarithm of the ratio of an input voltage signal to a reference voltage signal comprising in combination: a source of exponentially varying voltage; first means for comparing the voltage from said source with said input voltage signal to provide a first signal manifestation at the instant in time when the absolute values of the last two voltages are equal; second means for comparing the voltage from said source with said reference voltage signal to provide a second signal manifestation at the instant in time when the absolute values of the last two voltages are equal; and means coupled to said first and second means and responsive to said first and second signal manifestations for providing an output signal having a parameter proportional to the time interval between the occurrence of said two signal manifestations, said first signal manifestation being represented by a change in signal from said first means from a representation of a logical 1 to a logical 0, and said second signal manifestation being represented by a change in signal from said second means from a representation of a logical 0 to a logical 1; and said means for providing an output signal comprising a logical operator circuit for providing a logical 1 output signal only when said signals from said first and second means represent simultaneously the same logical condition and otherwise providing a logical 0 output signal.
Claim 5
Dependent Claim
243 words
Apparatus for providing an output signal having a parameter proportional to the logarithm of the ratio of an input voltage signal to a reference voltage signal comprising in combination: a source of exponentially varying voltage; first means for comparing the voltage from said source with said input voltage signal to provide a first signal manifestation at the instant in time when the absolute values of the last two voltages are equal; second means for comparing the voltage from said source with said reference voltage signal to provide a second signal manifestation at the instant in time when the absolute values of the last two voltages are equal; and means coupled to said first and second means and responsive to said first and second signal manifestations for providing an output signal having a parameter proportional to the time interval between the occurrence of said two signal manifestations, said first signal manifestation being represented by a change in signal from said first means from a representation of a logical 1 to a logical 0, and said second signal manifestation being represented by a change in signal from said second means from a representation of a logical 0 to a logical 1; and said means for providing an output signal comprising a logical operator circuit for providing a logical 1 output signal only when said signals from said first and second means represent simultaneously the same logical condition and otherwise providing a logical 0 output signal.
Claim 6
Dependent Claim
46 words
Apparatus according to claim 3, wherein a summing amplifier circuit is provided having its input coupled to said first and second means responsive to said signals therefrom for providing a signal indicative of the sign of said input voltage signal relative to said reference voltage signal.
Claim 7
Dependent Claim
179 words
Apparatus for providing an output signal having a parameter proportional to the logarithm of the ratio of an input voltage signal to a reference voltage signal comprising in combination: a source of exponentially varying voltage; first means for comparing the voltage from said source with said input voltage signal to provide a first signal manifestation at the instant in timE when the absolute values of the last two voltages are equal; second means for comparing the voltage from said source with said reference voltage signal to provide a second signal manifestation at the instant in time when the absolute values of the last two voltages are equal; and means coupled to said first and second means and responsive to said first and second signal manifestations for providing an output signal having a parameter proportional to the time interval between the occurrence of said two signal manifestations, and means coupled to said first and second means responsive to the signals therefrom for providing a signal indicative of the sign of said input voltage signal relative to said reference voltage signal.
Claim 8
Dependent Claim
179 words
Apparatus for providing an output signal having a parameter proportional to the logarithm of the ratio of an input voltage signal to a reference voltage signal comprising in combination: a source of exponentially varying voltage; first means for comparing the voltage from said source with said input voltage signal to provide a first signal manifestation at the instant in timE when the absolute values of the last two voltages are equal; second means for comparing the voltage from said source with said reference voltage signal to provide a second signal manifestation at the instant in time when the absolute values of the last two voltages are equal; and means coupled to said first and second means and responsive to said first and second signal manifestations for providing an output signal having a parameter proportional to the time interval between the occurrence of said two signal manifestations, and means coupled to said first and second means responsive to the signals therefrom for providing a signal indicative of the sign of said input voltage signal relative to said reference voltage signal.
Claim 9
Dependent Claim
243 words
Apparatus for providing an output signal having a parameter proportional to the logarithm of the ratio of an input voltage signal to a reference voltage signal comprising in combination: a source of exponentially varying voltage; keying means coupled to said source for determining the initiation of each exponential voltage wave produced by said source; first means for comparing the voltage from said source with said input voltage signal to provide a first signal manifestation at the instant in time when the absolute values of the last two voltages are equal; second means for comparing the voltage from said source with said reference voltage signal to provide a second signal manifestation at the instant in time when the absolute values of the last two voltages are equal; means coupled to said first and second means and responsive to said first and second signal manifestations for providing a gating pulse signal having a duration proportional to the time interval between the occurrence of said two signal manifestations; means for providing pulses of relatively short duration with substantially constant periodicity; a gating circuit coupled to both said last mentioned means and to said means for providing a gating pulse signal for passing a train of said pulses in the presence of said gating pulse signal, the number of pulses in said train representing said parameter; and means coupling the pulses from said pulse providing means to said keying means for synchronizing the operation of the latter.
Claim 10
Dependent Claim
243 words
Apparatus for providing an output signal having a parameter proportional to the logarithm of the ratio of an input voltage signal to a reference voltage signal comprising in combination: a source of exponentially varying voltage; keying means coupled to said source for determining the initiation of each exponential voltage wave produced by said source; first means for comparing the voltage from said source with said input voltage signal to provide a first signal manifestation at the instant in time when the absolute values of the last two voltages are equal; second means for comparing the voltage from said source with said reference voltage signal to provide a second signal manifestation at the instant in time when the absolute values of the last two voltages are equal; means coupled to said first and second means and responsive to said first and second signal manifestations for providing a gating pulse signal having a duration proportional to the time interval between the occurrence of said two signal manifestations; means for providing pulses of relatively short duration with substantially constant periodicity; a gating circuit coupled to both said last mentioned means and to said means for providing a gating pulse signal for passing a train of said pulses in the presence of said gating pulse signal, the number of pulses in said train representing said parameter; and means coupling the pulses from said pulse providing means to said keying means for synchronizing the operation of the latter.
Claim 11
Dependent Claim
111 words
Apparatus according to claim 6, wherein said first signal manifestation is represented by a change in signal from said first means from a representation of a logical 1 to a logical 0, and said second signal manifestation is represented by a change in signal from said second means from a representation of a logical 0 to a logical 1; and wherein said means for providing a gating pulse signal comprises a logical operator circuit for providing a logical 1 output signal representing said gating pulse when said signals from said first and second means represent simultaneously the same logical condition, and at all other times providing a logical 0 output signal.
Claim 12
Dependent Claim
46 words
Apparatus according to claim 7, wherein a summing amplifier circuit is provided having its input coupled to said first and second means responsive to said signals therefrom for providing a signal indicative of the sign of said input voltage signal relative to said reference voltage signal.
Claim 13
Dependent Claim
40 words
Apparatus according to claim 6, wherein means are provided coupled to said first and second means responsive to the signals therefrom for providing a signal indicative of the sign of said input voltage signal relative to said reference voltage 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) | 1975-09-12 | 1976-03-13 | 1976-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-12 | 1980-03-13 | 1980-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-12 | 1984-03-13 | 1984-09-12 | $7700.00 | Window Closed / Lapsed |