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. 11, 1983
Filed:
Jan. 17, 1980
Applicant:
Inventors:
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04H / ; H04N / ;
U.S. Cl.
CPC ...
179 / ; 179 / ; 455 71 ; 328138 ; 358144 ;
Abstract
A discriminator apparatus for a television multivoice system comprises a mixer for mixing a program identifying signal with a reference signal thereby to produce a differential beat signal. A reference signal generator includes a signal source of an original frequency, and a frequency converter for converting the original frequency to the reference frequency which is close to the frequency of the program identifying signal and so selected that the frequency of the differential beat signal is lower than the lowest audible frequency. A low-pass filter is employed for extracting the differential beat signal. Need for expensive mechanical filters of a narrow fractional bandwidth is thereby eliminated.