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:
Nov. 12, 1985
Filed:
Sep. 19, 1983
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
In a double superheterodyne tuner, the first local oscillator frequency is set to a value higher than the first intermediate frequency, which is set to a value between three and five times the upper limit of the receiving frequency range. With this arrangement spurious signals of at least third or less order can be prevented from occuring in the first intermediate frequency range. The tuner comprises an input filter which attenuates interference signals whose harmonics equal a desired frequency. The second intermediate frequency may be selected such that it is obtained by subtracting the second local oscillator frequency from the first intermediate frequency which is higher than the second local oscillator frequency. As a bandpass filter for passing the first intermediate frequency may be used a coaxial dielectric filter so as to reduce interferences by undesired channel signals.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile