US3852670A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tuner with integral input filter
Assignee: Zenith Electronics LLC
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Filing: 1973-10-29
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Granted: 1974-12-03
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Expires: 1993-10-29
Abstract
Abstract A television tuner has a UHF section comprising a stamped metal subchassis having a plurality of resonant circuit elements whose electrical characteristics are adjustable by deforming portions thereof and a thick film integrated circuit VHF section. A metal housing supports the stamped metal subchassis and thick film integrated circuit and a metal shield encloses the stamped chassis and integrated circuit. The thick film integrated circuit includes an RF amplifier, mixer, local oscillatr, and an input filter network which attenuates signals between 88 and 108 MHz as well as those at or near the IF frequency of 45.75 MHz. The input filter network can be aligned while coupled to the RF amplifier input network.
Inventors
- 👤 J Ma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:25
CPC Classifications
H; H03; H03H; H03H2/00; H03H2/005; H03H2/008; H03J; H03J3/00; H03J3/02; H03J3/16; H03J3/18; H03J3/185; H03J5/00; H03J5/24; H03J5/242; H03J5/244
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
133 words
A television tuner for converting the frequency of a received signal to an intermediate frequency, said tuner comprising: a shielded housing; an RF amplifier, a mixer and a local oscillator stage in said shielded housing each including tuned circuit components having variable reactance, for adjusting the resonant frequencies of said stages; an input filter network in said shielded housing, coupling the received signal to said RF amplifier, and reducing the levels of signal frequencies within a predetermined band of frequencies; and means, including an RF amplifier input network, permitting alignment of said input filter network while coupled to said RF amplifier stage by altering the impedance of said RF amplifier input network to terminate said filter network, for signals within said band of frequencies, in an impedance suitable for alignment of said filter.
Claim 2
Dependent Claim
133 words
A television tuner for converting the frequency of a received signal to an intermediate frequency, said tuner comprising: a shielded housing; an RF amplifier, a mixer and a local oscillator stage in said shielded housing each including tuned circuit components having variable reactance, for adjusting the resonant frequencies of said stages; an input filter network in said shielded housing, coupling the received signal to said RF amplifier, and reducing the levels of signal frequencies within a predetermined band of frequencies; and means, including an RF amplifier input network, permitting alignment of said input filter network while coupled to said RF amplifier stage by altering the impedance of said RF amplifier input network to terminate said filter network, for signals within said band of frequencies, in an impedance suitable for alignment of said filter.
Claim 3
Dependent Claim
41 words
A television tuner as set forth in claim 1, wherein said RF amplifier input network includes: a transformer coupling the output of said filter network to said RF amplifier stage; and means for resonating said transformer to provide said suitable impedance.
Claim 4
Dependent Claim
35 words
A television tuner as set forth in claim 2, wherein said means for resonating includes: a varactor diode, coupled to said transformer, having a capacitive reactance which varies as a function of applied DC voltage.
Claim 5
Dependent Claim
57 words
A television tuner as set forth in claim 3, wherein said input filter network includes: an FM filter having a plurality of adjustable resonant circuit elements reducing the levels of signals between 88 and 108 MHz; and an IF filter having a plurality of adjustable resonant circuit elements reducing the levels of signals at said intermediate frequency.
Claim 6
Dependent Claim
35 words
A television tuner as set forth in claim 3 wherein said RF amplifier, mixer and local oscillator stages together with said input filter network and said means for aligning are combined on an insulating base.
Claim 7
Dependent Claim
17 words
A television tuner as set forth in claim 5 wherein said insulating base comprises an alumina substrate.
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) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |