Patent ID: 8090011
Filing Date: 2012-01-03
Classification: H04L

Abstract:
1. A measuring apparatus which measures a quadrature modulator for applying quadrature modulation to an I (in-phase) signal and a Q (quadrature phase) signal input thereto by a carrier signal having a carrier frequency, the measuring apparatus comprising: a supplying section which supplies the quadrature modulator with a reference I (in-phase) signal having a predetermined frequency and a reference Q (quadrature phase) signal whose phase is shifted by 90 degrees from the reference I (in-phase) signal; an extracting section which extracts, from a modulation signal output from the quadrature modulator as a result of applying quadrature modulation to the reference I (in-phase) signal and the reference Q (quadrature phase) signal, a main signal component which is a result of modulating the reference I (in-phase) signal and the reference Q (quadrature phase) signal, and an image signal component which occurs at a position symmetric to the modulated reference I (in-phase) signal and reference Q (quadrature phase) signal with respect to the carrier signal; and a measurement value calculating section comprising a processor which calculates at least one of a carrier phase error which occurs between an I (in-phase) signal side and a Q (quadrature phase) signal side of the quadrature modulator, an amplitude error between the I (in-phase) signal side and the Q (quadrature phase) signal side of the quadrature modulator, and a skew between an I (in-phase) signal and a Q (quadrature phase) signal of the quadrature modulator based on the main signal component and the image signal component, wherein the measurement value calculating section includes: