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:
Feb. 17, 2004
Filed:
Oct. 15, 2001
Jouko Vankka, Helsinki, FI;
Nokia Corporation, Espoo, FI;
Abstract
Known digital QAM modulators use sine/cosine memories and a plurality of multipliers. This can be avoided by replacing the circuitry which carries out the circular rotation of [I(n), Q(n)]T performed in all the QAM modulators, with a CORDIC algorithm. The invented QAM modulator is comprised of a plurality of digital rotation stages ( ) coupled in sequence. The first stage ( ) receives the I and Q data streams and the last stage ( ) outputs a vector comprising of the orthogonal I and Q components of a digital intermediate frequency signal. Each of the rotation stages rotates an input vector applied to the stage at a predetermined elementary rotation angle, said input vector being the output vector of the previous digital rotation stage. The modulator further includes an angle computation block ( ) for counting the elementary rotation angles for the rotation stages. The angle computation block is connected to the phase accumulator which receives a frequency control word (F ) and based on that word generates an input word (Z ) applied to the angle computation block.