US3704414A
Expired / Lapsed
US
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Frequency meter
Assignee: BOGUE ELECTRIC Manufacturing Co
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Filing: 1971-01-18
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Granted: 1972-11-28
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Expires: 1991-01-18
Abstract
Abstract A frequency monitor for giving a meter indication of the frequency of a signal utilizes a zero-crossing detector to control the counting of clock pulses to a pair of cascaded binary counters. The first counter covers the bulk of the period between zero crossings and the second counter covers the remainder thereof. The count in the second counter is periodically stored and fed to a digital-to-analog converter which includes means for performing an analog linearization of currents which energize a meter; such meter being calibrated in Hertz per unit current.
Inventors
- 👤 John A Herbst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:16
CPC Classifications
G; G01; G01R; G01R23/00; G01R23/02; G01R23/10
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
218 words
Apparatus for measuring the frequency of a periodically recurring signal comprising means for indicating the start of each cycle of the periodically recurring signal, a source of pulses having a frequency much higher than the frequency of the periodically recurring signal, first and second pulse counters, switching means for controllably connecting said source of pulses alternately to said first and second pulse counter, said switching means including first means responsive to said start of cycle indicating means to control said switching means to connect said source of pulses to the input of said first counter at the start of each cycle, and second means responsive to said first counter to connect said source of pulses to the input of said second counter whenever the pulse count in said first counter reaches a predetermined value, a count memory means connected to the output of said second counter for controllably storing the pulse count in said second counter, means connected to said indicating means for controlling said count memory means to store the count in said second counter at the start of each cycle of the periodically recurring signal, and means connected to said count memory means for converting the stored pulse count of said second counter to a linear analog representation of the frequency of the periodically recurring signal.
Claim 2
Dependent Claim
218 words
Apparatus for measuring the frequency of a periodically recurring signal comprising means for indicating the start of each cycle of the periodically recurring signal, a source of pulses having a frequency much higher than the frequency of the periodically recurring signal, first and second pulse counters, switching means for controllably connecting said source of pulses alternately to said first and second pulse counter, said switching means including first means responsive to said start of cycle indicating means to control said switching means to connect said source of pulses to the input of said first counter at the start of each cycle, and second means responsive to said first counter to connect said source of pulses to the input of said second counter whenever the pulse count in said first counter reaches a predetermined value, a count memory means connected to the output of said second counter for controllably storing the pulse count in said second counter, means connected to said indicating means for controlling said count memory means to store the count in said second counter at the start of each cycle of the periodically recurring signal, and means connected to said count memory means for converting the stored pulse count of said second counter to a linear analog representation of the frequency of the periodically recurring signal.
Claim 3
Dependent Claim
157 words
Apparatus as in claim 1 wherein said switching means comprises: a latch having a set input, a reset input, a set output, and a reset output; a first two-input AND-gate; and a second two-input AND-gate, means for connecting the output of said indicating means to the set input of said latch, means for connecting a particular output of said first counter to the reset input of said latch, means for connecting the set output of said latch to one input of said first two-input AND-gate, means for connecting the reset output of said latch to one input of said second two-input AND-gate, means for connecting the output of said source of pulses to the second input of each of said two-input AND-gates, means for connecting the output of said first two-input AND-gate to the input of said first counter and means for connecting the output of said second two-input AND-gate to the input of said second counter.
Claim 4
Dependent Claim
74 words
Apparatus as in claim 2 wherein each of said counters has a clearing input and further comprising means connected to the clearing input of said first counter for clearing said first counter whenever the count therein reaches said predetermined value and means connected to the clearing input of said second counter for clearing said second counter whenever the count in said first counter reaches a particular value which is less than said predetermined value.
Claim 5
Dependent Claim
106 words
Apparatus as in claim 2 wherein said means for connecting the output of said second two-input AND-gate to said second counter comprises a third two-input AND-gate and a multi-input NAND-gate, means for connecting the output of said second two-input AND-gate to one input of said third two-input AND-gate, means for connecting the output of said third two-input AND-gate to the input of said second counter, means for connecting the output of said multi-input NAND-gate to the second input of said third two-input AND-gate, and means for connecting each of the inputs of said multi-input NAND-gate to a different one of the outputs of said second counter.
Claim 6
Dependent Claim
74 words
The apparatus of claim 4 wherein each of said counters has a clearing input and further comprises means connected to said clearing input of said first counter for clearing said first counter whenever the count therein reaches said predetermined value and means connected to the clearing input of said second counter for clearing said second counter whenever the count in said first counter reaches a particular value which is less than said predetermined value.
Claim 7
Dependent Claim
99 words
The apparatus of claim 1 wherein said means for converting the stored count to an analog representation comprises an input amplifier for generating an input Current, a digital-to-analog converting means for scaling said input current to values inversely related to the digital representation of the stored pulse count, an output amplifier having an input for receiving the scaled current and an output transmitting a signal proportional to the received scaled current and means connected to the output of said output amplifier for converting the signal therefrom to a linear visual representation of the frequency of a period recurring signal.
Claim 8
Dependent Claim
36 words
The apparatus of claim 6 wherein said input amplifier is an operational amplifier having an input and further comprising feedback means for connecting the output of said output amplifier to the input of said input amplifier.
Claim 9
Dependent Claim
46 words
The apparatus of claim 7, further comprising an inverting current amplifier connecting the output of said input amplifier to the input of said output amplifier in parallel with said digital-to-analog converting means for zero adjusting the scaled current received at the input of said output amplifier.
Claim 10
Dependent Claim
89 words
The apparatus of claim 4 wherein said means for converting the stored count to an analog representation comprises an input amplifier for generating an input current, a digital-to-analog converting means for scaling said input current to values related to the digital representation of the stored pulse count, an output amplifier having an input for receiving the scaled current and an output transmitting a signal proportional to the received scaled current and means connected to the output of said output amplifier for converting the signal therefrom to a visual representation.
Claim 11
Dependent Claim
76 words
The apparatus of claim 9 wherein said input amplifier is an operational amplifier having an input and further comprising feedback means for connecting the output of said output amplifier to the input of said input amplifier, and an inverting current amplifier connecting the output of said input amplifier to the input of said output amplifier in parallel with said digital-to-analog converting means for zero adjusting the scaled current received at the input of said output amplifier.
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) | 1975-11-28 | 1976-05-29 | 1976-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-28 | 1980-05-29 | 1980-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-28 | 1984-05-29 | 1984-11-28 | $7700.00 | Window Closed / Lapsed |