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. 27, 1997
Filed:
Aug. 03, 1995
Clinton C Powell, II, Lake Worth, FL (US);
Edward K Lee, Sunrise, FL (US);
Hyuck M Kwon, Wichita, KS (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A communication device with a synchronized zero-crossing demodulator is described. A synchronizer system (123, 223, 125, 227) and method derives symbol transition timing information from a zero-crossing detector output. The synchronizer (123, 223) is, in one embodiment, connected to the output of a zero-crossing detector (120, 220), to provide an edge clock signal to a phase angle estimator (122, 226), which is passed to a decision device 124, which provides a symbol estimate which is later decoded into an information message. In an alternative embodiment, a synchronizer is combined with the phase angle estimator (125, 227) to provide as an output, a phase angle estimate which is passed to a decision device (124) which provides a symbol estimate signal (127, 229), which is later decoded to obtain the information message. The alternative embodiment allows recovery of the second symbol which is typically lost in implementing the first embodiment of the system, to avoid second order error effects on recovered data.