Patent US3568034A successfully refreshed from Google Patents.
US3568034A
Expired / Lapsed
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Power line harmonic comb filter
Assignee: United States Department of the Navy
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Filing: 1969-10-22
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Granted: 1971-03-02
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Expires: 1989-10-22
Abstract
Abstract A low frequency comb filter having a 60 cycle stepdown transformer source input which is applied across a full-wave and a half-wave rectifier employing limiting diodes. The rectified outputs are then applied to a plurality of channels each having therein a constant impedance level control circuit, a band-pass filter, and a variable phase generator. The resultant channel outputs thereof are connected to a common line to provide an input for a component in which the interference is to be canceled via a decoupling element. Amplitude and phase are adjusted to provide positive cancellation.
Inventors
- 👤 Saul Shenfeld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 07:36
CPC Classifications
H; H02; H02M; H02M1/00; H02M1/14; H02M1/143
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
187 words
A harmonic comb filter for generating phase and amplitude controlled fundamental and harmonics thereof which comprises: a source of fundamental frequency; a limiting rectifier means having full-wave and half-wave outputs and connected to receive said source; a fundamental channel connected directly to said source and having connected in series therein; a fundamental variable amplitude control means; a fundamental phase control means; and a decoupling means; a plurality of harmonic channels each having connected in series therein; variable harmonic amplitude control means; a band-pass filter means for passing therethrough a single harmonic different from the other filters of said plurality of channels; a variable harmonic phase control means; a harmonic decoupling means; electrical means connecting said harmonic channels of even harmonics to said full-wave output of said rectifier means, and said odd harmonic channels to said half-wave output; and a common line have connected thereto said harmonic decoupling and said decoupling means; whereby the fundamental and harmonics thereof will be present simultaneously on said common line and may be individually adjusted in amplitude and phase so as to permit cancellation when coacted with undesirable signals of like frequencies.
Claim 2
Dependent Claim
187 words
A harmonic comb filter for generating phase and amplitude controlled fundamental and harmonics thereof which comprises: a source of fundamental frequency; a limiting rectifier means having full-wave and half-wave outputs and connected to receive said source; a fundamental channel connected directly to said source and having connected in series therein; a fundamental variable amplitude control means; a fundamental phase control means; and a decoupling means; a plurality of harmonic channels each having connected in series therein; variable harmonic amplitude control means; a band-pass filter means for passing therethrough a single harmonic different from the other filters of said plurality of channels; a variable harmonic phase control means; a harmonic decoupling means; electrical means connecting said harmonic channels of even harmonics to said full-wave output of said rectifier means, and said odd harmonic channels to said half-wave output; and a common line have connected thereto said harmonic decoupling and said decoupling means; whereby the fundamental and harmonics thereof will be present simultaneously on said common line and may be individually adjusted in amplitude and phase so as to permit cancellation when coacted with undesirable signals of like frequencies.
Claim 3
Dependent Claim
56 words
The comb filter according to claim 1 wherein said rectifier includes: a stepdown transformer whose secondary has a grounded center tap; a pair of limiting diodes connected across said secondary to provide a full-wave output therebetween and said center tap; and another limiting diode connected to one side of said secondary to provide a half-wave output.
Claim 4
Dependent Claim
31 words
The comb filter according to claim 2 further including a Zener diode connected to clip and limit said harmonic input to said harmonic channels of odd harmonics greater than the third.
Claim 5
Dependent Claim
18 words
The comb filter according to claim 3 wherein said variable fundamental and harmonic amplitude control means are potentiometers.
Claim 6
Dependent Claim
13 words
The comb filter according to claim 4 wherein said decoupling means are resistors.
Claim 7
Dependent Claim
78 words
The comb filter according to claim 5 further including; a variable filter means having an input and output; an oscilloscope having its input connected to said output of said variable filter means; and whereby when said undesirable signals and the comb filter output on said common line are coacted and simultaneously applied to said filter input, cancellation thereof may be accomplished by selective operation of said variable amplitude and phase while adjusting said filter and observing said oscilloscope.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |