Patent US2074886A successfully refreshed from Google Patents.
US3727140A
Expired / Lapsed
US
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A uhf and vhf tuner for television
Assignee: Individual
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Filing: 1969-10-09
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Granted: 1973-04-10
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Expires: 1989-10-09
Abstract
Abstract UHF and VHF tuner for television. The tuner has a radioamplifier for all bands in which silicon transistors with amplifying elements are used. The transistor of the radioamplifier is used in common emitter for UHF and in common base for VHF, the commutation of bands being accomplished by means of diodes of commutation. The oscillator-mixer for the UHF is formed of a transistor in common base while the local oscillator of the UHF band uses as a variable capacity diode a variable tuning element. The VHF oscillator which uses a transistor in common emitter amplifies the intermediate frequency (I.F.) of the UHF.
Inventors
- 👤 C Nieto
- 👤 L Vera
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:53
CPC Classifications
H; H03; H03J; H03J5/00; H03J5/24; H03J5/242; H03J5/244
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
352 words
In a UHF and VHF tuner for television having a circuit having a radioamplifier transistor in a common emitter configuration for VHF and in a common base configuration for UHF, an improvement in means for changing the circuit configuration for the transistor, said improvement comprising a first diode having the anode grounded, a first condenser in the circuit between the first diode and the emitter of said transistor so that when the diode is conductive the high frequency currents are short-circuited to ground, whereby the transistor is connected in the circuit in a common emitter configuration for VHF, an admittance filter for the VHF band signals coupled to said base of said transistor for connecting the circuit in common base configuration for UHF and comprised of two filters in parallel, one for Band I signals and the other for the Band III signals, the filter for Band III VHF signals having one capacitor and a self-induction coil in series with said capacitor forming a series resonant circuit which resonates at the center of the Band III, a further capacitor coupled between the base and emitter of said transistor, and a further coil coupled between said self-induction coil and ground which is in parallel with the further capacitor, a second diode in series with said Band III filter, said Band I filter being an asymmetric type filter with reactAnce to ground having a T section configuration with two arms each having a capacitor and self-inductances which resonate at the center of the Band I at a frequency of 58 MHz, and further having a base composed of a capacitor and a coil connected to the junction between said legs and ground and resonating at a frequency of 36 MHz forming a doubly tuned circuit with a mutual coupling of said base, whereby the Band I filter operates when said second diode does not conduct and the Band III filter operates when said second diode conducts so that the signal at the frequency of Band III is conducted to the base of the transistor while the signals of the Band I filter are grounded.
Claim 2
Dependent Claim
352 words
In a UHF and VHF tuner for television having a circuit having a radioamplifier transistor in a common emitter configuration for VHF and in a common base configuration for UHF, an improvement in means for changing the circuit configuration for the transistor, said improvement comprising a first diode having the anode grounded, a first condenser in the circuit between the first diode and the emitter of said transistor so that when the diode is conductive the high frequency currents are short-circuited to ground, whereby the transistor is connected in the circuit in a common emitter configuration for VHF, an admittance filter for the VHF band signals coupled to said base of said transistor for connecting the circuit in common base configuration for UHF and comprised of two filters in parallel, one for Band I signals and the other for the Band III signals, the filter for Band III VHF signals having one capacitor and a self-induction coil in series with said capacitor forming a series resonant circuit which resonates at the center of the Band III, a further capacitor coupled between the base and emitter of said transistor, and a further coil coupled between said self-induction coil and ground which is in parallel with the further capacitor, a second diode in series with said Band III filter, said Band I filter being an asymmetric type filter with reactAnce to ground having a T section configuration with two arms each having a capacitor and self-inductances which resonate at the center of the Band I at a frequency of 58 MHz, and further having a base composed of a capacitor and a coil connected to the junction between said legs and ground and resonating at a frequency of 36 MHz forming a doubly tuned circuit with a mutual coupling of said base, whereby the Band I filter operates when said second diode does not conduct and the Band III filter operates when said second diode conducts so that the signal at the frequency of Band III is conducted to the base of the transistor while the signals of the Band I filter are grounded.
Claim 3
Dependent Claim
67 words
The improvement as claimed in claim 1 further comprising radiofrequency band filter of a doubly tuned type in the form of a transformer for very high frequency and having a resonant primary and secondary and having coils for Band I and Band III signals and a lambda /2 (Lambda/2) line for UHF signals being all in series in the primary and in the secondary of said filter.
Claim 4
Dependent Claim
44 words
The improvement as claimed in claim 2 in which the band filter for UHF signals comprises lambda /2 (Lambda/2) lines having characteristic impedances on the order of 110 at 140 ohms and having at the ends diodes and variable capacitors for tuning the diodes.
Claim 5
Dependent Claim
46 words
The improvement as claimed in claim 2 in which the band filter for UHF signals comprises lambda /2 (Lambda/2) and open circuits having characteristics impedances on the order of 110 at 140 ohms and having at the ends diodes and variable capacitors for tuning the diodes.
Claim 6
Dependent Claim
58 words
The improvement as claimed in claim 3 further comprising a mixer for the VHF signals having a transistor and a plurality of coils coupled thereto and magnetically coupled with the coil of the secondary of the filter for the Band III signals and having a capacitor coupled with the secondary of the filter for the Band I signals.
Claim 7
Dependent Claim
65 words
The improvement as claimed in claim 3 further comprising an oscillator-mixer for the UHF band signals comprising a transistor coupled in a common base configuration and having a tuning circuit coupled to the collector with a lambda /2 (Lambda/2) line and a diode having a variable capacitor coupled to the end thereof and having a characteristic impedance on the order of 110 to 140 ohms.
Claim 8
Dependent Claim
43 words
The improvement as claimed in claim 6 in which the lambda /2 (Lambda/2) lines of the primary and secondary of the radiofrequency band filter and the lambda /2 (Lambda/2) line of the oscillator have lengths on the order of 30 to 35 centimeters.
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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) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |