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US4491809A
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US
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Matching circuit for a pre-amplifier of SHF band television signal receiver
Assignee: Hitachi Ltd
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Filing: 1982-08-09
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Granted: 1985-01-01
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Expires: 2002-08-09
Abstract
Abstract A matching circuit for a pre-amplifier of an SHF band television signal receiver is disclosed. The matching circuit comprises a stub line arranged near a gate terminal of an FET, and a pair of stub lines connected to a transmission line, one being a stub line exhibiting a short circuit impedance at a lower frequency than operating frequencies of the matching circuit and the other being a stub line arranged oppositely to the stub line and exhibiting a short circuit at a higher frequency than the operating frequencies. A distance between the stub line and the pair of stub lines is selected to be approximately equal to 1/4 wavelength of a center frequency of the desired signal band.
Inventors
- 👤 Masaki Noda
- 👤 Keiro Shinkawa
- 👤 Chuichi Sodeyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:17
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/60; H03F3/601; H01; H01P; H01P5/00; H01P5/02; H01P5/022; H01P5/028; H03F1/00; H03F1/56
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
229 words
A matching circuit for a pre-amplifier of an SHF band television signal receiver, the operating frequency band of said matching circuit including a first, a second, and a third frequency, said first frequency being lower than said third frequency, said second frequency being substantially the center between said first and third frequencies, said matching circuit comprising: (a) impedance matching means connected to a terminal of an amplifying device of said pre-amplifier; (b) a transmission line connected to said impedance matching means, said transmission line being arranged oppositely to said amplifying device; and (c) a first and a second stub line connected to said transmission line and spaced from said impedance matching means by a distance approximately equal to (2n-1)/4 wavelength (n=1,2,3, . . . ) of a wave of said second frequency, said first and second stub lines being arranged oppositely to each other with respect to said transmission line, said first stub line having a length selected so as to present an inductive impedance in said operating frequency band of said matching circuit and present substantially a short circuit at an image frequency of said second frequency, said second stub line having a length selected so as to present a capacitive impedance in said operating frequency band of said matching circuit and present an admittance which cancels an admittance of said first stub line at said second frequency.
Claim 2
Dependent Claim
229 words
A matching circuit for a pre-amplifier of an SHF band television signal receiver, the operating frequency band of said matching circuit including a first, a second, and a third frequency, said first frequency being lower than said third frequency, said second frequency being substantially the center between said first and third frequencies, said matching circuit comprising: (a) impedance matching means connected to a terminal of an amplifying device of said pre-amplifier; (b) a transmission line connected to said impedance matching means, said transmission line being arranged oppositely to said amplifying device; and (c) a first and a second stub line connected to said transmission line and spaced from said impedance matching means by a distance approximately equal to (2n-1)/4 wavelength (n=1,2,3, . . . ) of a wave of said second frequency, said first and second stub lines being arranged oppositely to each other with respect to said transmission line, said first stub line having a length selected so as to present an inductive impedance in said operating frequency band of said matching circuit and present substantially a short circuit at an image frequency of said second frequency, said second stub line having a length selected so as to present a capacitive impedance in said operating frequency band of said matching circuit and present an admittance which cancels an admittance of said first stub line at said second frequency.
Claim 3
Dependent Claim
29 words
A matching circuit according to claim 1, in which said impedance matching means is constituted by a transformer of a 1/4 wavelength of the wave of said second frequency.
Claim 4
Dependent Claim
37 words
A matching circuit according to claim 1, in which said impedance matching means is constituted by a connecting line connected to said terminal of said amplifying device and a third stub line connected to said connecting line.
Claim 5
Dependent Claim
23 words
A matching circuit according to claim 1, in which said impedance matching means is connected to an input terminal of said amplifying device.
Claim 6
Dependent Claim
23 words
A matching circuit according to claim 1, in which said impedance matching means is connected to an output terminal of said amplifying device.
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) | 1988-01-01 | 1988-07-02 | 1989-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-01 | 1992-07-02 | 1993-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-01 | 1996-07-02 | 1997-01-01 | $7700.00 | Window Closed / Lapsed |