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US3983494A
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Frequency insensitive sine wave-to-cosine wave converter
Assignee: General Electric Co
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Filing: 1975-03-24
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Granted: 1976-09-28
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Expires: 1995-03-24
Abstract
Abstract Variable frequency sine waves are converted to constant amplitude cosine waves using the relationship cos ωt = √1-sin 2 ωt. The converter has an almost instantaneous response characteristic and is suitable for a wide frequency range. An application is cosine timing waves for phase controlled converters and cycloconverters.
Inventors
- 👤 Bimal K. Bose
- 👤 Paul M. Espelage
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:23
CPC Classifications
G; G06; G06G; G06G7/00; G06G7/12; G06G7/22; H; H02; H02M; H02M5/00; H02M5/02; H02M5/04; H02M5/22; H02M5/25; H02M5/27; H02M5/271
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
177 words
A frequency insensitive sine wave-to-cosine wave converter based on the relationship cos ωt = √1-sin 2 ωt comprising first circuit means for continuously multiplying a variable frequency sine wave input signal by itself to generate a first signal representative of the square sin 2 ωt, second circuit means for effectively level shifting said first signal to generate a second signal representative of the difference 1-sin 2 ωt, and third circuit means for effectively taken the square root of said second signal to generate a cosine wave output signal with an amplitude proportional to the input signal amplitude, said second circuit means being comprised by a clamping circuit and a sign inverter circuit, and said third circuit means being comprised by a square rooter circuit for generating a full wave rectified cosine wave, a polarizer circuit for converting said full wave rectified cosine wave to the alternating voltage cosine wave output signal, and a polarizer control circuit for generating control signals for said polarizer circuit at intervals corresponding to the zero crossings of said cosine wave output signal.
Claim 2
Dependent Claim
177 words
A frequency insensitive sine wave-to-cosine wave converter based on the relationship cos ωt = √1-sin 2 ωt comprising first circuit means for continuously multiplying a variable frequency sine wave input signal by itself to generate a first signal representative of the square sin 2 ωt, second circuit means for effectively level shifting said first signal to generate a second signal representative of the difference 1-sin 2 ωt, and third circuit means for effectively taken the square root of said second signal to generate a cosine wave output signal with an amplitude proportional to the input signal amplitude, said second circuit means being comprised by a clamping circuit and a sign inverter circuit, and said third circuit means being comprised by a square rooter circuit for generating a full wave rectified cosine wave, a polarizer circuit for converting said full wave rectified cosine wave to the alternating voltage cosine wave output signal, and a polarizer control circuit for generating control signals for said polarizer circuit at intervals corresponding to the zero crossings of said cosine wave output signal.
Claim 3
Dependent Claim
154 words
A frequency insensitive sine wave-to-cosine wave converter based on the relationship cos ω t = √1-sin 2 ωt comprising an analog multiplier circuit for continuously multiplying by itself a variable frequency sine wave input signal to generate a first signal representative of the sine wave squared, a clamping circuit for effectively level shifting said first signal by an amount equal to the square of the peak amplitude of said first signal to thereby generate a second signal, a sign inverter circuit for instantaneously changing the polarity of said second signal and generating a third signal representative of the cosine wave squared, an analog square rooter circuit for taking the square root of said third signal and generating a full wave rectified cosine wave signal, and a polarizer circuit for converting said full wave rectified cosine wave signal to an alternating voltage cosine wave output signal having an amplitude proportional to the input signal amplitude.
Claim 4
Dependent Claim
154 words
A frequency insensitive sine wave-to-cosine wave converter based on the relationship cos ω t = √1-sin 2 ωt comprising an analog multiplier circuit for continuously multiplying by itself a variable frequency sine wave input signal to generate a first signal representative of the sine wave squared, a clamping circuit for effectively level shifting said first signal by an amount equal to the square of the peak amplitude of said first signal to thereby generate a second signal, a sign inverter circuit for instantaneously changing the polarity of said second signal and generating a third signal representative of the cosine wave squared, an analog square rooter circuit for taking the square root of said third signal and generating a full wave rectified cosine wave signal, and a polarizer circuit for converting said full wave rectified cosine wave signal to an alternating voltage cosine wave output signal having an amplitude proportional to the input signal amplitude.
Claim 5
Dependent Claim
48 words
A sine wave-to-cosine wave converter according to claim 2 wherein said clamping circuit is comprised by a capacitor connected in series between said analog multiplier circuit and said sign inverter circuit, and a diode effectively connected between the junction of said capacitor and sign inverter circuit and ground.
Claim 6
Dependent Claim
34 words
A sine wave-to-cosine wave converter according to claim 3 further including a voltage follower circuit connected between said analog multiplier circuit and said capacitor to present a low source impedance to said clamping circuit.
Claim 7
Dependent Claim
77 words
A sine wave-to-cosine wave converter according to claim 3 wherein said polarizer circuit is comprised by an inverting and noninverting amplifier, and a polarizer control circuit including a flip-flop connected to effectively control said inverting and noninverting amplifier, said polarizer control circuit further including means for actuating said flip-flop to change state and therefore cause said amplifier to alternately produce inverting and noninverting outputs at intervals corresponding to the zero crossings of said cosine wave output signal.
Claim 8
Dependent Claim
107 words
A sine wave-to-cosine wave converter according to claim 5 wherein said means for actuating said flip-flop to change state includes an integrator circuit for converting said sine wave input signal to a control circuit cosine wave, a pulse former circuit for producing a train of pulses corresponding to the zero crossings of said control circuit cosine wave that are coupled to a first input of said flip-flop, and a zero crossing detector circuit for converting said sine wave input signal to rectangular wave signals that are respectively coupled to a second input of said flip-flop an through an inverter circuit to a third input of said flip-flop.
Claim 9
Dependent Claim
25 words
A sine wave-to-cosine wave converter according to claim 6 further including a sign inverter circuit connected between said square rooter circuit and said polarizer circuit.
References Cited (Backward Citations)
US3639847A
Cited
US3675137A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-28 | 1980-03-29 | 1980-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-28 | 1984-03-29 | 1984-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-28 | 1988-03-29 | 1988-09-28 | $7700.00 | Window Closed / Lapsed |