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:
May. 06, 1986
Filed:
Mar. 07, 1984
Georges Bonnerot, Les Ulis, FR;
Michel Daout, Epinay sur Orge, FR;
Abstract
A circuit for recovering the carrier of an amplitude-and-phase-modulated input signal (in particular QAM signal) is provided with a frequency-controlled oscillator for producing the carrier, with a quadrature detector for supplying signals representing the amplitude of the input signal projected on two quadrature components P and Q of the carrier signal produced by the oscillator and for thus determining the modulation states of the input signal, and with correction means for forming a correction signal for the frequency control of the oscillator on the basis of output signals from a circuit which determines zones in the plane of the quadrature components P and Q. To provide for a satisfactory operation also in the presence of selective fading, the correction means comprises a weighting circuit connected to the zone-determining circuit for producing the correction signal in accordance with distinct weights allocated to the respective zones defined by the zone-determining circuit.