US4710705A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Noise removal circuit for use in a partial discharge measuring device of a high voltage apparatus
Assignee: Fuji Electric Co Ltd
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Filing: 1985-09-26
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Granted: 1987-12-01
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Expires: 2005-09-26
Abstract
Abstract A noise removal circuit for use in partial discharge measuring device of a high voltage apparatus. The circuit includes a first phase shift/reduction device responsive to an input signal for passing it directly while delaying it by a predetermined time and for reducing the delayed signal from the directly passed signal a second phase shift/reduction device for passing an output of the first phase shift/reduction device directly while delaying the output by the predetermined time and for reducing the delayed signal from the directly passes signal, and a phase shift/multiplying device for directly passing an output signal of the second phase shift/reduction device while delaying it by a time twice the predetermined time and multiplying the directly passed signal with the delayed signal.
Inventors
- 👤 Osamu Kawabata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 00:11
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/12; G01R31/1227; G01R31/1254
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
199 words
A noise removing circuit for use in a partial discharge measuring device for use with a high voltage apparatus responsive to an input signal composed of a partial discharge pulse signal having a pulse width in a predetermined time range and periodic noise having a period of time longer than said predetermined time range for removing the noise without deforming a waveform of the partial discharge pulse signal, said circuit comprising: first phase shift/reduction means, responsive to the input signal, for passing the input signal directly and delaying the input signal by a predetermined time, for reducing the delayed input signal with the directly passed input signal and producing an output, second phase shift/reduction means for passing the output of the first phase shift/reduction means directly and delaying the output by the predetermined time for reducing the delayed output with the directly passed output and producing an output signal, and phase shift/multiplying means for directly passing the output signal of the second phase shift/reduction means while delaying the output signal by a time twice as much as the predetermined time and for multiplying the directly passed output signal from the second phase shift/reduction means with the delayed output signal.
Claim 2
Dependent Claim
199 words
A noise removing circuit for use in a partial discharge measuring device for use with a high voltage apparatus responsive to an input signal composed of a partial discharge pulse signal having a pulse width in a predetermined time range and periodic noise having a period of time longer than said predetermined time range for removing the noise without deforming a waveform of the partial discharge pulse signal, said circuit comprising: first phase shift/reduction means, responsive to the input signal, for passing the input signal directly and delaying the input signal by a predetermined time, for reducing the delayed input signal with the directly passed input signal and producing an output, second phase shift/reduction means for passing the output of the first phase shift/reduction means directly and delaying the output by the predetermined time for reducing the delayed output with the directly passed output and producing an output signal, and phase shift/multiplying means for directly passing the output signal of the second phase shift/reduction means while delaying the output signal by a time twice as much as the predetermined time and for multiplying the directly passed output signal from the second phase shift/reduction means with the delayed output signal.
Claim 3
Dependent Claim
17 words
The circuit as claimed in claim 1, wherein said predetermined time is 2 nS to 4 nS.
Claim 4
Dependent Claim
17 words
The circuit as claimed in claim 1, wherein said predetermined time is 10 nS to 30 nS.
Claim 5
Dependent Claim
57 words
The circuit as claimed in any of claim 1 to 3, wherein each of said first and second phase shift/reduction means comprises a 180° distributor composed of a high frequency transformer and a mixer composed of one of a high frequency transformer and resistance means, said 180° distributor being connected through a delay circuit to said mixer.
Claim 6
Dependent Claim
34 words
The circuit as claimed in any of claim 1 to 3, wherein said predetermined time is variable according to a width of the partial discharge pulse signal dependent upon the kind of partial discharge.
Claim 7
Dependent Claim
37 words
The circuit as claimed in any of claim 1 to 3, wherein said input signal is supplied to said first phase shift/reduction means through a bandpass amplifier having a pass band of 50 MHz to 1000 MHz.
Claim 8
Dependent Claim
30 words
The circuit as claimed in claim 4, wherein said predetermined time is variable according to a width of the partial discharge pulse signal dependent upon the kind of partial discharge.
Claim 9
Dependent Claim
32 words
The circuit as claimed in claim 4, wherein said input signal is supplied to said first phase shift/reduction means through a bandpass amplifier having a passband of 50 MHz to 1000 MHz.
Claim 10
Dependent Claim
32 words
The circuit as claimed in claim 5, wherein said input signal is supplied to said first phase shift/reduction means through a bandpass amplifier having a passband of 50 MHz to 1000 MHz.
References Cited (Backward Citations)
US2799734A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-11-30 | 1991-06-01 | 1991-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-30 | 1995-06-01 | 1995-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-30 | 1999-06-01 | 1999-12-01 | $7700.00 | Window Closed / Lapsed |