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. 29, 1994
Filed:
Dec. 23, 1992
Didier Martineau, Andresy, FR;
Thomson-LGT Laboratoire General des Telecommunications, Conflans Sainte Honorine, FR;
Abstract
The disclosure relates to the changing of frequencies. The mixing of a signal at a frequency Fe and of the signal of a local oscillator gives a resultant signal that comprises a first component at the useful frequency, a second component at the frequency of the oscillator and a third component which is an image of the first component with respect to the second one. A filtering highly attenuates the third component. A servo-control makes a part of the signal from the oscillator undergo variations in amplitude and phase before adding it to the resultant signal to be filtered; the variations are made so as to obtain a minimum energy from the second component before filtering. Application to the changing of frequencies with suppression of the component at the frequency of the local oscillator.