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:
Aug. 02, 1988
Filed:
Oct. 30, 1985
John Y Ma, Milpitas, CA (US);
Capetronic (BSR) Ltd., Kowloon, HK;
Abstract
A method of reducing terrestrial interference is provided for a TVRO earth station receiver comprising a super-heterodyne circuit including a voltage-controlled oscillator (VCO), a mixer for combining incoming first IF signals with the output of the VCO to reduce the frequency of the first IF signals to a second IF range having a predetermined nominal center frequency, a pass band filter for filtering the second IF signals and having a pass band centered on the nominal second IF center frequency, and a microprocessor for controlling the input voltage to the VCO and for automatically setting the controlling input voltage at prescribed levels in response to a 'channel select' command signal, so that the VCO produces an output frequency which centers the received signal for a selected channel on the nominal second IF center frequency. The method includes offsetting the controlling input voltage from the prescribed level for a selected channel to offset the actual second IF center frequency relative to the center of the pass band of the filter, in a direction that removes at least a portion of the terrestrial interference from the pass band.