Fundamental frequency and period detector
First Claim
1. A process for detecting the fundamental frequency of each cycle of a series of contiguous cycles of an alternating current input wave from an alternating current source, wherein each sequential cycle in the series is treated as the current cycle, and the following contiguous cycle is treated as the succeeding cycle, comprising the steps of:
- (A) starting to integrate the amplitudes of the current cycle of the input wave when the amplitude of the input wave exceeds a given amplitude in a given polarity;
(B) continuing to integrate the amplitudes of the current cycle of the input wave for a first given period of time which is less than the shortest expected wave period being detected and during said first period of time ignoring the value of the integral;
(C) continuing to integrate the amplitudes of the current cycle of the input wave for a second period of time until the value of the integral reaches a threshold voltage set above the highest expected end of cycle value of the integral;
(D) resetting and maintaining the value of the integral at said starting value prior to the input wave again reaching said given amplitude in said given polarity; and
(E) again starting to integrate the amplitudes of the input wave when the amplitude of the succeeding cycle of the input wave exceeds said given amplitude in said given polarity;
(F) measuring the time between any given event in the steps (A) through (D) for the current cycle and the corresponding event in the steps (A) through (D) for the succeeding cycle, whereby said measured time represents the period of the fundamental frequency; and
(G) dividing one by the period of the fundamental frequency to obtain the fundamental frequency.
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Abstract
Fundamental frequency and period detector processes and systems which determine the end of a cycle of an ac waveform by using the characteristic of the integral of a single cycle of an ac waveform that the value of the integral at the end of the cycle is the same as at the cycle start despite cycle noise, multiple zero crossings and other cycle obscuration. These processes and systems use the cycle integral to self-synchronize with each cycle of an ac waveform. Formation of the cycle integral of each processed cycle is a useful by-product of the frequency and period detection processes and systems.
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Citations
95 Claims
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1. A process for detecting the fundamental frequency of each cycle of a series of contiguous cycles of an alternating current input wave from an alternating current source, wherein each sequential cycle in the series is treated as the current cycle, and the following contiguous cycle is treated as the succeeding cycle, comprising the steps of:
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(A) starting to integrate the amplitudes of the current cycle of the input wave when the amplitude of the input wave exceeds a given amplitude in a given polarity; (B) continuing to integrate the amplitudes of the current cycle of the input wave for a first given period of time which is less than the shortest expected wave period being detected and during said first period of time ignoring the value of the integral; (C) continuing to integrate the amplitudes of the current cycle of the input wave for a second period of time until the value of the integral reaches a threshold voltage set above the highest expected end of cycle value of the integral; (D) resetting and maintaining the value of the integral at said starting value prior to the input wave again reaching said given amplitude in said given polarity; and (E) again starting to integrate the amplitudes of the input wave when the amplitude of the succeeding cycle of the input wave exceeds said given amplitude in said given polarity; (F) measuring the time between any given event in the steps (A) through (D) for the current cycle and the corresponding event in the steps (A) through (D) for the succeeding cycle, whereby said measured time represents the period of the fundamental frequency; and (G) dividing one by the period of the fundamental frequency to obtain the fundamental frequency. - View Dependent Claims (65, 66, 67)
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2. A system for detecting the fundamental frequency of each cycle of a series of cycles of an alternating current input wave from an alternating current source, wherein each sequential cycle in the series is treated in what follows as the current cycle, and the following contiguous cycle is treated as the succeeding cycle, comprising:
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(A) threshold sensing means responsive to the beginning of a current cycle of the input wave for sensing when the input wave exceeds a given amplitude in a given polarity; (B) integrator means responsive to said threshold sensing means during said current cycle of the input wave for (1) starting to integrate the amplitudes of the current cycle of the input wave when the amplitude of the input wave exceeds said given amplitude in a given polarity, said integration thereby starting from a predetermined integrator means reset value, and (2) continuing to integrate the amplitudes of the current cycle of the input wave for a first given period of time which is less than the shortest expected input wave period and during said first period of time ignoring the value of the integral until at least it departs from said predetermined integrator means reset value; (C) comparator means for comparing the value of the integral with a reference value above the highest expected end of cycle value of the integral; (D) said integrator means continuing to integrate the amplitudes of the current cycle of the input wave during said current cycle of the input wave for a second period of time until said comparator means determines that the value of the integral is insubstantially different from said reference value; (E) reset means responsive to said comparator means during the current cycle of the input wave for resetting said integrator means to said predetermined integrator means reset value prior to the input wave again reaching said given amplitude in said given polarity; (F) measuring means for measuring the time between a given event in the system during a current cycle of the input wave and the corresponding event in the system during the succeeding cycle to determine the period of the fundamental frequency of a cycle of the input wave; and (G) dividing means for dividing one by the period of the fundamental frequency to obtain the fundamental frequency.
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3. A system for detecting the fundamental frequency of each cycle of a series of cycles of an alternating current input wave from an alternating current source, wherein each sequential cycle in the series is treated as the current cycle, and the following contiguous cycle is treated as the succeeding cycle, comprising:
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(A) threshold sensing means responsive to the beginning of a current cycle of the input wave for sensing when the input wave exceeds a given amplitude in a given polarity; (B) integrator means responsive to said threshold sensing means during said current cycle of the input wave for (1) starting to integrate the amplitudes of the current cycle of the input wave when the amplitude of the input wave exceeds said given amplitude in a given polarity, said integration thereby starting from a predetermined integrator means reset value, and (2) continuing to integrate the amplitudes of the current cycle of the input wave for a first given period of time which is less than the shortest expected input wave period and during said first period of time ignoring the value of the integral until at least it departs from said predetermined integrator means reset value; (C) comparator means for comparing the value of the integral with said predetermined integrator means reset value during said current cycle of the input wave; (D) said integrator means continuing to integrate the amplitudes of the current cycle of the input wave during said current cycle of the input wave for a second period of time until said comparator means determines that the value of the integral is insubstantially different from said predetermined integrator means reset value; (E) reset means responsive to said comparator means during the current cycle of the input wave for resetting said integrator means to said predetermined integrator means reset value prior to the input wave again reaching said given amplitude in said given polarity; (F) measuring means for measuring the time between a given event in the system during a current cycle of the input wave and the corresponding event in the system during the succeeding cycle to determine the period of the fundamental frequency of a cycle of the input wave; and (G) dividing means for dividing one by the period of the fundamental frequency to obtain the fundamental frequency. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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46. A process for detecting the period of the fundamental frequency of a single cycle of an alternating current waveform from an alternating current source comprising the steps of:
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(A) changing the value of an output variable upon detection of a departure from a zero value of the alternating current waveform, and thereafter ignoring further departures from subsequent zero values of the alternating current waveform; (B) starting to integrate the amplitudes of the alternating current waveform cycle when the amplitude of the alternating current waveform exceeds a given amplitude; (C) continuing thereafter to integrate the amplitudes of the alternating current waveform for a first given period of time which is less than the shortest expected alternating current waveform cycle and during said first given period of time ignoring the value of the integral; (D) continuing thereafter to integrate the amplitudes of the alternating current waveform cycle until the value of the integral is insubstantially different from its value when the integration started; (E) waiting thereafter until occurrence of a zero value of the alternating current waveform, and thereupon changing the value of an output variable; (F) whereby the period of the output variable changes represents the detected period of the input cycle of an alternating current waveform from an alternating current source. - View Dependent Claims (47, 48)
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49. A process for detecting the fundamental frequency of each cycle of a series of contiguous cycles of an alternating current input wave from an alternating current source, wherein each sequential cycle in the series is treated as the current cycle, and the following contiguous cycle is treated as the succeeding cycle, comprising the steps of:
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(A) starting to integrate the amplitudes of the current cycle of the input wave when the amplitude of the input wave exceeds a given amplitude in a given polarity; (B) continuing to integrate the amplitudes of the current cycle of the input wave for a first given period of time which is less than the shortest expected wave period being detected and during said first period of time ignoring the value of the integral; (C) continuing to integrate the amplitudes of the current cycle of the input wave for a second period of time until the value of the integral is insubstantially different from its value when the integration started in step (A); (D) maintaining the value of the integral at said starting value prior to the input wave again reaching said given amplitude in said given polarity; and (E) repeating steps (A) through (D) for the succeeding cycle of the input wave; (F) measuring the time between any given event in the steps (A) through (D) for the current cycle and the corresponding event in the step (A) through (D) for the succeeding cycle, whereby said measured time represents the period of the fundamental frequency; and (G) dividing one by the period of the fundamental frequency to obtain the fundamental frequency. - View Dependent Claims (50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64)
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68. A process for determining the period of the fundamental frequency of a signal having an amplitude variation with respect to a predetermined variable for a portion of the signal having a waveform for which the integral of the amplitude of the waveform relative a predetermined reference level is substantially zero, said process comprising the steps of:
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(A) integrating the amplitude of said waveform with respect to said predetermined variable to produce a related integration value, said integration starting from a first value of said predetermined variable at which said waveform has an amplitude substantially equal to a predetermined amplitude; (B) selecting a second value of said predetermined variable using said first value, said second value functioning as a reference value for establishing a full cycle of the fundamental frequency; (C) comparing said related integration value of the integral obtained in step (A) to a predetermined integration value; and (D) using the information in step (C) to obtain a third value of said variable corresponding to a point on said waveform spaced apart from said second value by an amount approximately equal to the full cycle of the fundamental frequency; whereby the period of the fundamental frequency of said waveform is determined. - View Dependent Claims (69, 70, 71, 72, 73, 74, 75, 76, 77)
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78. A system for determining the period of the fundamental frequency of a signal having an amplitude variation with respect to a predetermined variable for a portion of the signal having a waveform for which the integral of the amplitude of the waveform relative a predetermined reference level is substantially zero, said system comprising:
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(A) integrating means operable for integrating the amplitude of said waveform with respect to said predetermined variable to produce a related integration value, said integration starting from a first value of said predetermined variable at which said waveform has an amplitude substantially equal to a predetermined amplitude; (B) selecting means operable for selecting a second value of said predetermined variable using said first value, said second value functioning as a reference value for establishing a full cycle of the fundamental frequency; (C) comparing means operable for comparing said related integration value of the integral obtained with said integrating means to a predetermined integration value; and (D) processing means operable for using the information obtained from said comparing means to obtain a third value of said variable corresponding to a point on said waveform spaced apart from said second value by an amount approximately equal to the full cycle of the fundamental frequency; whereby the period of the fundamental frequency of said waveform is determined. - View Dependent Claims (79, 80, 81, 82, 83, 84, 85, 86, 87)
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88. A process for detecting the period of the fundamental frequency of each cycle of a series of contiguous cycles of an alternating current input wave from an alternating current source, wherein each sequential cycle in the series is treated as the current cycle, and the following contiguous cycle is treated as the succeeding cycle, comprising the steps of:
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(A) starting to integrate the amplitudes of the current cycle of the input wave when the amplitude of the input wave exceeds a given amplitude in a given polarity; (B) continuing to integrate the amplitudes of the current cycle of the input wave for a first given period of time which is less than the shortest expected wave period being detected and during said first period of time ignoring the value of the integral; (C) continuing to integrate the amplitudes of the current cycle of the input wave for a second period of time until the value of the integral is insubstantially different from its value when the integration started in step (A); (D) maintaining the value of the integral at said starting value prior to the input wave again reaching said given amplitude in said given polarity; (E) repeating steps (A) through (D) for the succeeding cycle of the input wave; and (F) measuring the time between any given event in the steps (A) through (D) for the current cycle and the corresponding event in the steps (A) through (D) for the succeeding cycle, whereby said measured time represents the period of the fundamental frequency.
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89. A process for detecting the period of the fundamental frequency of each cycle of a series of contiguous cycles of an alternating current input wave from an alternating current source, wherein each sequential cycle in the series is treated as the current cycle, and the following contiguous cycle is treated as the succeeding cycle, comprising the steps of:
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(A) starting to integrate the amplitudes of the current cycle of the input wave when the amplitude of the input wave exceeds a given amplitude in a given polarity; (B) continuing to integrate the amplitudes of the current cycle of the input wave for a first given period of time which is less than the shortest expected wave period being detected and during said first period of time ignoring the value of the integral; (C) continuing to integrate the amplitudes of the current cycle of the input wave for a second period of time until the value of the integral reaches a threshold voltage set above the highest expected end of cycle value of the integral; (D) resetting and maintaining the value of the integral at said starting value prior to the input wave again reaching said given amplitude in said given polarity; and (E) again starting to integrate the amplitudes of the input wave when the amplitude of the succeeding cycle of the input wave exceeds said given amplitude in said given polarity; and (F) measuring the time between any given event in the steps (A) through (D) for the current cycle and the corresponding event in the steps (A) through (D) for the succeeding cycle, whereby said measured time represents the period of the fundamental frequency.
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90. A system for detecting the period of the fundamental frequency of each cycle of a series of cycles of an alternating current input wave from an alternating current source, wherein each sequential cycle in the series is treated as the current cycle, and the following contiguous cycle is treated as the succeeding cycle, comprising:
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(A) threshold sensing means responsive to the beginning of a current cycle of the input wave for sensing when the input wave exceeds a given amplitude in a given polarity; (B) integrator means responsive to said threshold sensing means during said current cycle of the input wave for (1) starting to integrate the amplitudes of the current cycle of the input wave when the amplitude of the input wave exceeds said given amplitude in a given polarity, said integration thereby starting from a predetermined integrator means reset value, and (2) continuing to integrate the amplitudes of the current cycle of the input wave for a first given period of time which is less than the shortest expected input wave period and during said first period of time ignoring the value of the integral until at least it departs from said predetermined integrator means reset value; (C) comparator means for comparing the value of the integral with said predetermined integrator means reset value during said current cycle of the input wave; (D) said integrator means continuing to integrate the amplitudes of the current cycle of the input wave during said current cycle of the input wave for a second period of time until said comparator means determines that the value of the integral is insubstantially different from said predetermined integrator means reset value; (E) reset means responsive to said comparator means during the current cycle of the input wave for resetting said integrator means to said predetermined integrator means reset value prior to the input wave again reaching said given amplitude in said given polarity; and (F) measuring means for measuring the time between a given event in the system during a current cycle of the input wave and the corresponding event in the system during the succeeding cycle to determine the period of the fundamental frequency of a cycle of the input wave.
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91. A system for detecting the fundamental frequency of each cycle of a series of cycles of an alternating current input wave from an alternating current source, wherein each sequential cycle in the series is treated in what follows as the current cycle, and the following contiguous cycle is treated as the succeeding cycle, comprising:
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(A) threshold sensing means responsive to the beginning of a current cycle of the input wave for sensing when the input wave exceeds a given amplitude in a given polarity; (B) integrator means responsive to said threshold sensing means during said current cycle of the input wave for (1) starting to integrate the amplitudes of the current cycle of the input wave when the amplitude of the input wave exceeds said given amplitude in a given polarity, said integration thereby starting from a predetermined integrator means reset value, and (2) continuing to integrate the amplitudes of the current cycle of the input wave for a first given period of time which is less than the shortest expected input wave period and during said first period of time ignoring the value of the integral until at least it departs from said predetermined integrator means reset value; (C) comparator means for comparing the value of the integral with a reference value above the highest expected end of cycle value of the integral; (D) said integrator means continuing to integrate the amplitudes of the current cycle of the input wave during said current cycle of the input wave for a second period of time until said comparator means determines that the value of the integral is insubstantially different from said reference value; (E) reset means responsive to said comparator means during the current cycle of the input wave for resetting said integrator means to said predetermined integrator means reset value prior to the input wave again reaching said given amplitude in said given polarity; and (F) measuring means for measuring the time between a given event in the system during a current cycle of the input wave and the corresponding event in the system during the succeeding cycle to determine the period of the fundamental frequency of a cycle of the input wave.
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92. A process for detecting the period of the fundamental frequency of each cycle of a series of contiguous cycles of an alternating current input wave from an alternating current source, wherein each sequential cycle in the series is treated as the current cycle, and the following contiguous cycle is treated as the succeeding cycle, comprising the steps of:
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(A) starting to integrate the amplitudes of the current cycle of the input wave when the amplitude of the input wave exceeds a given amplitude in a given polarity; (B) continuing to integrate the amplitudes of the current cycle of the input wave for a first given period of time which is less than the shortest expected wave period being detected and during said first period of time ignoring the value of the integral; (C) continuing to integrate the amplitudes of the current cycle of the input wave for a second period of time until the value of the integral is insubstantially different from its value when the integration started in step (A); (D) repeating steps (A) through (C) for the succeeding cycle of the input wave; (E) whereby the period of repetition of the process (A) through (C) is synchronized with the period of the fundamental frequency of the current cycle of the input wave, said period of repetition being the detected period of the fundamental frequency of the input wave.
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93. A process for detecting the period of the fundamental frequency of each cycle of a series of contiguous cycles of an alternating current input wave from an alternating current source, wherein each sequential cycle in the series is treated as the current cycle, and the following contiguous cycle is treated as the succeeding cycle, comprising the steps of:
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(A) starting to integrate the amplitudes of the current cycle of the input wave when the amplitude of the input wave exceeds a given amplitude in a given polarity; (B) continuing to integrate the amplitudes of the current cycle of the input wave for a first given period of time which is less than the shortest expected wave period being detected and during said first period of time ignoring the value of the integral; (C) continuing to integrate the amplitudes of the current cycle of the input wave for a second period of time until the value of the integral reaches a threshold voltage set above the highest expected end of cycle value of the integral; (D) again starting to integrate the amplitudes of the input wave when the amplitude of the succeeding cycle of the input wave exceeds said given amplitude in said given polarity; (E) whereby the period of repetition of the process (A) through (C) is synchronized with the period of the fundamental frequency of the current cycle of the input wave, said period of repetition being the detected period of the fundamental frequency of the input wave.
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94. A system for detecting the period of the fundamental frequency of each cycle of a series of cycles of an alternating current input wave from an alternating current source, wherein each sequential cycle in the series is treated as the current cycle, and the following contiguous cycle is treated as the succeeding cycle, comprising:
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(A) threshold sensing means responsive to the beginning of a current cycle of the input wave for sensing when the input wave exceeds a given amplitude in a given polarity; (B) integrator means responsive to said threshold sensing means during said current cycle of the input wave for (1) starting to integrate the amplitudes of the current cycle of the input wave when the amplitude of the input wave exceeds said given amplitude in a given polarity, said integration thereby starting from a predetermined integrator means reset value, and (2) continuing to integrate the amplitudes of the current cycle of the input wave for a first given period of time which is less than the shortest expected input wave period and during said first period of time ignoring the value of the integral until at least it departs from said predetermined integrator means reset value; (C) comparator means for comparing the value of the integral with said predetermined integrator means reset value during said current cycle of the input wave; (D) said integrator means continuing to integrate the amplitudes of the current cycle of the input wave during said current cycle of the input wave for a second period of time until said comparator means determines that the value of the integral is insubstantially different from said predetermined integrator means reset value; (E) whereby the period of repetition of system actions (A) through (D) is synchronized with the period of the fundamental frequency of the current cycle of the input wave, said period of repetition being the detected period of the fundamental frequency of the input wave.
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95. A system for detecting the fundamental frequency of each cycle of a series of cycles of an alternating current input wave from an alternating current source, wherein each sequential cycle in the series is treated in what follows as the current cycle, and the following contiguous cycle is treated as the succeeding cycle, comprising:
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(A) threshold sensing means responsive to the beginning of a current cycle of the input wave for sensing when the input wave exceeds a given amplitude in a given polarity; (B) integrator means responsive to said threshold sensing means during said current cycle of the input wave for (1) starting to integrate the amplitudes of the current cycle of the input wave when the amplitude of the input wave exceeds said given amplitude in a given polarity, said integration thereby starting from a predetermined integrator means reset value, and (2) continuing to integrate the amplitudes of the current cycle of the input wave for a first given period of time which is less than the shortest expected input wave period and during said first period of time ignoring the value of the integral until at least it departs from said predetermined integrator means reset value; (C) comparator means for comparing the value of the integral with a reference value above the highest expected end of cycle value of the integral; (D) said integrator means continuing to integrate the amplitudes of the current cycle of the input wave during said current cycle of the input wave for a second period of time until said comparator means determines that the value of the integral is substantially different from said reference value; (E) whereby the period of repetition of system actions (A) through (D) is synchronized with the period of the fundamental frequency of the current cycle of the input wave, said period of repetition being the detected period of the fundamental frequency of the input wave.
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Specification