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. 06, 2009
Filed:
Sep. 13, 2005
Gopinath Patra, Bangalore, IN;
Gopinath Patra, Bangalore, IN;
Ittiam Systems (P) Ltd., Bangalore, Karnataka, IN;
Abstract
A method and apparatus for a frequency shift keying (FSK) demodulator use a configuration to improve the autocorrelation for better receiver performance. The demodulator uses parallel first and second lines connected to the same input signal, the first line having a delay element to provide an integer-delay of M, the second parallel line having a filter for causing a group delay of τ+M where τ is fractional, and a multiplier for receiving the signals from said first and second lines and generating a resultant signal from which a base band signal can be recovered. The resultant signal is passed through a low pass base band filter to recover the base band signal. τ may have a value of 3.25 and M may be 6. The demodulator may selectively be implemented in caller ID service and in low end modems chosen from a group comprising V.21, Bell 103, V.23 and Bell 202A modems.