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. 16, 2001
Filed:
May. 13, 1997
Christian Guillemain, Sannois, FR;
Abdelkrim Ferrad, Puteaux, FR;
Alcatel Telspace, Nanterre Cedex, FR;
Abstract
The invention relates to a system for detecting the presence of a carrier wave in a digital signal that is available at a given frequency. The system delivers at least two baseband samples of the digital signal at each symbol time. The system comprises a timing estimator responsive to the baseband samples to deliver an error signal (&egr;) corresponding to the phase error between the clock frequency that is to be recovered and a local clock frequency, and a detector that generates a detection signal indicating that a carrier wave has been detected whenever a level representative of the variance of the error signal (&egr;) reaches a threshold value. The invention is particularly applicable to receivers of signals transmitted in DTMA mode.