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:
Aug. 25, 2009
Filed:
Jan. 27, 2005
Ravi Kumar, Koramangla, IN;
Priyanka Agarwal, Indira Nagar, IN;
V. Pravin Kumar, Ulsoor, IN;
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A system and method is disclosed for demodulating RF amplitude modulated signals in a demodulator circuit of an EPC0 compliant RFID tag. One advantageous embodiment of the invention comprises first and second input ports, a +ve envelope detector circuit for each of the first and second input ports, a −ve envelope detector circuit for each of the first and second input ports, a +ve envelope differentiator circuit, a +ve low pass filter, a −ve envelope differentiator circuit, a −ve low pass filter, and a zero crossing detector. The zero crossing detector detects a transition in the RF input signal using a voltage difference between a +ve filtered differentiated envelope signal and a −ve filtered differentiated envelope signal.