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. 30, 2001
Filed:
Dec. 29, 1997
Christian Guillemain, Sannois, FR;
Abdelkrim Ferrad, Aubervilliers, FR;
Alcatel, Paris, FR;
Abstract
An apparatus estimates the frequency difference existing between the carrier frequency of a received digital signal and the frequency of a signal from a local oscillator contained in a receiver of the received signal. The receiver performs quadrature demodulation on the received signal. The apparatus includes a detector that detects the noise level received in the band of the receive filters, a processor for computing discrete Fourier transforms on the received signal transposed into baseband, a summer for summing the energy levels detected on either side of the center frequency of the receive filters, a subtractor for subtracting the noise level from the energy bands, and a comparator for comparing the resultant energy levels and delivering an estimate &egr; of the frequency difference.