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:
Oct. 20, 1992
Filed:
Apr. 01, 1991
Donald B Lemersal, Jr, Park Ridge, IL (US);
Thomas J Walczak, Woodstock, IL (US);
Robert J Greene, Streamwood, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A modulator circuit for generating a modulated, DQPSK signal. The modulator circuit includes an encoder for receiving a binary bit stream comprised of bit pairs defining differential phase changes. An encoder receives a bit stream of which bit pairs thereof define differential phase changes. The encoder encodes the bit pairs into codewords which are stored and then supplied to an I-accumulator, a Q-accumulator, and a memory element. The memory element contains pre-multiplied values which are supplied to the I- and the Q-accumulators which add terms of the pre-multiplied values to form I-portions and Q-portions of a DQPSK-modulated signal. The I- and Q-portions may then be supplied to a quadrature modulator.