Four band VHF varactor tuner
AssigneeZenith Radio Corporation
InventorFred H. Moon
Life of this patent
Estimating the term…
Abstract
A varactor controlled television receiver tuning system is operable for tuning all VHF and CATV television channels in four frequency bands including the low VHF band extending between 54-88 MHz, the mid/high VHF band extending between 120-216 MHz, the CATV superband extending between 216-300 MHz and a CATV hyperband extending between 300-400 MHz. The tuning system comprises a plurality of identically configured resonant circuits each responsive to a pair of band switching signals for assuming a total inductance for tuning each of the four different frequency bands, each of the resonant circuits being alignable by adjusting a different variable reactance element in each frequency band.
Claims7
In a television receiver of the type including a three-band varactor tuned resonant circuit comprising a varactor diode;
- first, second and third inductance means;
- and first and second switching means selectively operable for connecting three different combinations of said inductance means across said varactor diode for tuning three different television signal bands, the improvement comprising:
- means for selectively operating said first and second switching means for connecting four different combinations of said inductance means across said varactor diode to allow the tuning of four different VHF/CATV television signal bands;
- and
- tuning means connected in circuit with said inductance means and having a variable reactance adjustable for facilitating the alignment of said resonant circuit for tuning one of said four bands.
A resonant circuit for facilitating tuning a television receiver to a selected channel within one of four frequency bands comprising a low VHF band extending from 54 to 88 MHz, a mid/high VHF band extending from 120-216 MHz, a CATV superband extending from 216-300 MHz and a CATV hyperband extending from about 300 to about 400 MHz, said resonant circuit comprising:
- first, second and third variable inductance means;
- band switching means selectively operable for interconnecting said first, second and third inductance means in four different arrangements each characterized by a different value of total inductance and each adapted for tuning one of said four frequency bands;
- varactor diode means connected in circuit with said first, second and third inductance means and operable for, in association with said band switched first, second and third inductance means, tuning a selected channel in each of said four frequency bands;
- and
- manually adjustable variable reactance means connected in circuit with said inductance means, one of said first, second and third inductance means and said variable reactance means being manually adjustable for aligning said resonant circuit when operated for tuning each respective one of said four frequency bands.
Dependencies are inferred from the claim text.