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:
Jul. 25, 1995
Filed:
Aug. 25, 1994
Applicant:
Inventors:
J M Simard, Hull, CA;
William T Ross, Dunrobin, CA;
Assignee:
Northern Telecom Limited, Montreal, CA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03C / ; H04L / ;
U.S. Cl.
CPC ...
329303 ; 375317 ; 375334 ;
Abstract
A digital FSK demodulator used in e.g. a telephone loop produces unequal amplitudes in detected mark and space tones. The inequality or offset must be cancelled so that a proper timing signal can be recovered from the FSK signal. The demodulator includes a digital compensation circuit for offset cancellation in which peak amplitudes of digital 0 and digital 1 signals are continuously monitored. The peak amplitudes are then averaged to obtain an offset estimation which is subtracted from the output of the demodulator for offset compensation.