Patent US3718874A successfully refreshed from Google Patents.
US3718874A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Etched inductance bandpass filter
Assignee: Individual
•
Filing: 1970-12-29
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Granted: 1973-02-27
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Expires: 1990-12-29
Abstract
Abstract A bandpass filter of one or more stages using etched inductors and designed for use in the VHF or UHF ranges is disclosed. Three etched inductors are used in each stage, and a variable capacitor is used to tune the stage. Alternatively, the variable capacitor may be replaced by a fixed capacitor, and a variable inductor may be substituted for one of the fixed inductors. Coaxial cable may be used to couple stages together. A modified filter stage is also disclosed to simplify tuning procedures when filters having three cascaded stages are assembled.
Inventors
- 👤 R Cooper
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 06:27
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/01; H03H7/0153; H03H7/0161; H03H7/17; H03H7/1716; H03H7/1725; H03H7/1741; H03H7/1775
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
141 words
A bandpass filter circuit comprising: input means, first capacitor means for matching the impedance of said bandpass filter circuit with that of an input circuit coupled in series with said input means, second capacitor means for trimming said bandpass filter coupled in series with said first capacitor means, third capacitor means for matching the impedance of coupled in series with said capacitor means, said bandpass filter circuit with that of an output circuit, output means coupled in series with said third capacitor means, first etched inductor means coupled to the juncture of said first and second capacitor means, second etched inductor means identical to said first inductor means coupled to the juncture of said second and third capacitor means and to said first etched inductor means; and third inductor means coupled to the juncture of said first and second inductor means.
Claim 2
Dependent Claim
141 words
A bandpass filter circuit comprising: input means, first capacitor means for matching the impedance of said bandpass filter circuit with that of an input circuit coupled in series with said input means, second capacitor means for trimming said bandpass filter coupled in series with said first capacitor means, third capacitor means for matching the impedance of coupled in series with said capacitor means, said bandpass filter circuit with that of an output circuit, output means coupled in series with said third capacitor means, first etched inductor means coupled to the juncture of said first and second capacitor means, second etched inductor means identical to said first inductor means coupled to the juncture of said second and third capacitor means and to said first etched inductor means; and third inductor means coupled to the juncture of said first and second inductor means.
Claim 3
Dependent Claim
26 words
A bandpass filter circuit as in claim 1, wherein said second capacitor means comprises a variable capacitor and said third inductor means comprises an etched inductor.
Claim 4
Dependent Claim
26 words
A bandpass filter circuit as in claim 1, wherein said second capacitor means comprises a fixed capacitor and said third inductor means comprises a variable inductor.
Claim 5
Dependent Claim
116 words
A bandpass filter circuit comprising: input means, first capacitor means coupled to said input means, second capacitor means coupled to said first capacitor means, third capacitor means coupled to said second capacitor means, output means coupled to said third capacitor means, first etched inductor means coupled to the juncture of said first and second capacitor means, second etched inductor means coupled to the juncture of said second and third capacitor means and to said first etched inductor means, and, third inductor means coupled to the juncture of said first and second inductor means, a short length of non-resonant, low-impedance coaxial cable coupled to said output means, and, second bandpass filter means coupled to said coaxial cable.
Claim 6
Dependent Claim
116 words
A bandpass filter circuit comprising: input means, first capacitor means coupled to said input means, second capacitor means coupled to said first capacitor means, third capacitor means coupled to said second capacitor means, output means coupled to said third capacitor means, first etched inductor means coupled to the juncture of said first and second capacitor means, second etched inductor means coupled to the juncture of said second and third capacitor means and to said first etched inductor means, and, third inductor means coupled to the juncture of said first and second inductor means, a short length of non-resonant, low-impedance coaxial cable coupled to said output means, and, second bandpass filter means coupled to said coaxial cable.
Claim 7
Dependent Claim
51 words
A bandpass filter circuit as in claim 4, wherein said second bandpass filter means comprises: first, second, and third capacitors connected in series, first inductor connected between first and second capacitors, second inductor coupled between said second and third capacitors, and, third inductor coupled between said first and second inductor means.
Claim 8
Dependent Claim
17 words
A bandpass filter circuit as in claim 5, wherein: said first and second inductors are etched inductors.
Claim 9
Dependent Claim
17 words
A bandpass filter circuit as in claim 6, wherein: said etched inductors are of rectangular spiral configuration.
Claim 10
Dependent Claim
24 words
A bandpass filter circuit as in claim 6, wherein: said second capacitor is a variable capacitor, and said third inductor is an etched inductor.
Claim 11
Dependent Claim
24 words
A bandpass filter circuit as in claim 6, wherein: said second capacitor is a fixed capacitor and said third inductor is a variable inductor.
Claim 12
Dependent Claim
25 words
A bandpass filter circuit as in claim 6, further comprising: third bandpass filter means coupled to said third capacitor of said second bandpass filter means.
Claim 13
Dependent Claim
57 words
A bandpass filter circuit as in claim 10, wherein said third filter stage means comprises: first substage means, fixed capacitor means coupled to said first substage means, second substage means coupled to said first capacitor means, second fixed capacitor means coupled to said second substage means, and, third substage means coupled to said second fixed capacitor means.
Claim 14
Dependent Claim
27 words
A bandpass filter as in claim 11, wherein said first, second, and third substage means each compRise a variable capacitor connected in parallel to an etched inductor.
Claim 15
Dependent Claim
66 words
A bandpass filter circuit as in claim 4, further comprising: first, second and third substage means coupled to said second bandpass filter means, each substage means comprising an etched inductor and a variable capacitor connected in parallel, first fixed capacitor means coupling said first substage means to said second substage means; and, second fixed capacitor means coupling said second substage means to said third substage means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-27 | 1976-08-28 | 1977-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-27 | 1980-08-28 | 1981-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-27 | 1984-08-28 | 1985-02-27 | $7700.00 | Window Closed / Lapsed |