US3743940A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency measuring circuit
Assignee: COCO RES Inc
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Filing: 1971-11-02
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Granted: 1973-07-03
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Expires: 1991-11-02
Abstract
Abstract A frequency measuring circuit having a circuit for producing a sawtooth wave signal of a peak value corresponding to the pulse interval of an input pulse at every arrival thereof, an analog memory for storing the peak value of the sawtooth wave signal, a switching circuit for picking up the peak value of the sawtooth wave signal and supplying it to the analog memory to be memorized therein and an output circuit for deriving the content stored in the analog memory.
Inventors
- 👤 Y Yamagata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:05
CPC Classifications
G; G01; G01R; G01R23/00; G01R23/02; G01R23/06; G01R23/09; G01P; G01P3/00; G01P3/42; G01P3/44; G01P3/48; G01P3/4802
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
265 words
In a low speed tachometer wherein a pulse generator is provided in association with a rotary member whose speed is to be measured, and a pulse of a frequency proportional to the revolving speed of the rotary member is derived from the pulse generator and applied to a meter to indicate the revolving speed, the improvement therein comprising: a. pulse forming means 11,12,13 which produces a pulse signal of a pulse interval proportional to the rotational speed of the rotary member; b. a sawtooth wave generator 1 fed by said pulse forming means including a saw tooth forming capacitor 3 and a charging transistor 5 with a collector and positive and negative power source terminals; c. a field effect transistor 16 coupled to said generator 1, having a gate connected to said transistor collector, a drain connected to said positive terminal and a source coNnected to said negative terminal across a resistor 17; d. a blocking diode 19 connected to said source with a junction point, and an analog memory 18 connected to said source across said blocking diode 19 by being connected to said junction point; e. a switching transistor 20 connected to said junction point in opposite polarity to said blocking diode 19, including a base fed by said pulse forming means; and, f. a meter 25 in parallel between said field effect transisotr and said power source whereby the peak value of the generated sawtooth wave is stored in the analog memory which in turn feeds the meter 25 in response to pulse intervals corresponding to the speed of the rotary member.
Claim 2
Dependent Claim
265 words
In a low speed tachometer wherein a pulse generator is provided in association with a rotary member whose speed is to be measured, and a pulse of a frequency proportional to the revolving speed of the rotary member is derived from the pulse generator and applied to a meter to indicate the revolving speed, the improvement therein comprising: a. pulse forming means 11,12,13 which produces a pulse signal of a pulse interval proportional to the rotational speed of the rotary member; b. a sawtooth wave generator 1 fed by said pulse forming means including a saw tooth forming capacitor 3 and a charging transistor 5 with a collector and positive and negative power source terminals; c. a field effect transistor 16 coupled to said generator 1, having a gate connected to said transistor collector, a drain connected to said positive terminal and a source coNnected to said negative terminal across a resistor 17; d. a blocking diode 19 connected to said source with a junction point, and an analog memory 18 connected to said source across said blocking diode 19 by being connected to said junction point; e. a switching transistor 20 connected to said junction point in opposite polarity to said blocking diode 19, including a base fed by said pulse forming means; and, f. a meter 25 in parallel between said field effect transisotr and said power source whereby the peak value of the generated sawtooth wave is stored in the analog memory which in turn feeds the meter 25 in response to pulse intervals corresponding to the speed of the rotary member.
Claim 3
Dependent Claim
47 words
A frequency measuring circuit as claimed in claim 1, which further includes a delay circuit for delaying the input pulse and applying it as an control signal to the sawtooth wave signal generator circuit, the input pulse being applied as a control signal to the switching circuit.
Claim 4
Dependent Claim
46 words
A frequency measuring circuit as claimed in claim 2, wherein the sawtooth wave signal generator circuit includes components acting as an integration circuit for integrating a voltage with respect to time and a switching element for discharging or charging the integrated voltage with the control signal.
Claim 5
Dependent Claim
31 words
A frequency measuring circuit as claimed in claim 3, wherein the sawtooth wave signal generator circuit includes a high input impedance circuit for deriving the integrated voltage from the integration circuit.
Claim 6
Dependent Claim
25 words
A frequency measuring circuit as claimed in claim 2, wherein the analog memory is a capacitor and the output circuit is a high impedance circuit.
References Cited (Backward Citations)
US3553597A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-02 | 1977-01-01 | 1977-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-02 | 1981-01-01 | 1981-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-02 | 1985-01-01 | 1985-07-03 | $7700.00 | Window Closed / Lapsed |