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:
Nov. 27, 2012
Filed:
Oct. 07, 2008
Shoji Kojima, Tokyo, JP;
Shoji Kojima, Tokyo, JP;
Advantest Corporation, Tokyo, JP;
Abstract
A quadrature amplitude modulator is provided. An oscillator generates an in-phase carrier signal having a rectangular wave, a trapezoidal wave or a waveform similar to these, and a quadrature carrier signal, the phase of which is shifted by ¼ cycle relative to the in-phase carrier signal. A multi-level driver generates an in-phase modulated signal by amplitude modulating the in-phase carrier signal with an analog in-phase baseband signal having a discrete voltage level or current level in accordance with the in-phase baseband data. Likewise, the multi-level driver generates a quadrature modulated signal by amplitude modulating the quadrature carrier signal with an analog quadrature baseband signal having a discrete voltage level or current level in accordance with the quadrature baseband data The multi-level driver generates a modulated signal, the amplitude of which takes a discrete level, by combining the modulated signals together.