The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 28, 1978
Filed:
Dec. 06, 1976
Melvin Carlyle Hendrickson, Elmhurst, IL (US);
Zenith Radio Corporation, Glenview, IL (US);
Abstract
A television tuner system includes a varactor diode as the frequency determining element and means lacking a fine tuning control for addressing the varactor. In the addressing means, a plurality of DC potentials, each defining the band edges of one of the 82 standard broadcast television channels, are selectively accessible for deriving a nominal tuning voltage defining a frequency near the center of a selected channel and a pair of control voltages defining a restricted range of frequencies about the channel center frequency. The nominal tuning voltage is initially supplied to the varactor for tuning to the channel center frequency and is subsequently decoupled therefrom wherein tuning is maintained within the restricted range of frequencies by confining the voltage supplied to the varactor between the pair of control voltages. Automatic frequency control means are used to tune the varactor to a received signal within the restricted range of frequencies.