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:
Jan. 27, 1976
Filed:
Nov. 15, 1972
David E Lewis, Orange, CA (US);
Thomas F Gossard, Studio City, CA (US);
Columbia Pictures Industries, Inc., New York, NY (US);
Abstract
An individually addressable converter-tuner station for use in a cable television distribution system for selectively enabling the reception by conversion of at least one secure channel signal on a conventional television receiver. The converter-tuner utilizes a crystal-controlled local oscillator to provide the frequencies for converting the received secure channel carriers to a carrier receivable by the receiver. Initial filtration of the incoming secure channel carriers is accomplished in part by means of a tunable pass band filter, controlled by a variable capacitance diodes. A double balanced mixer is employed to cancel unwanted signals remaining in the filtered input to the mixer. The secure channel carriers are in the television midband range, and the local oscillator frequencies are below that range. Extensive use is made of diode switching of the crystal controlled oscillator and other components.