Patent ID: 7561629
Filing Date: 2009-07-14
Classification: H04L

Abstract:
1. A transmitter with a delay correcting function, including a digital modulator which digital-modulates a plurality of input baseband signals and outputs signals of I and Q phases, a D/A converter which converts the signals of I and Q phases outputted from said digital modulator to analog signals, a frequency converter which quadrature-modulates the analog signals of I and Q phases outputted from said D/A converter and upconverts the same into signals lying in an RF band, and a power amplifier which power-amplifies output signals of said frequency converter, said transmitter performing transmission of plural channels, said transmitter comprising: a mixer which downconverts the output signals of said power amplifier; and A/D converter which converts the output signals of said mixer into digital signals; a digital quadrature detector which quadrature-detects the output signals of said A/D converter to output signals of I and Q phases; a delay detector which supplies the signals of I and Q phases outputted from said digital modulator as transmit signals and supplies the signals of I and Q phases outputted from said digital quadrature detector as feedback signals, respectively, and which detects, as shifts in timing between the transmit signals and the feedback signals, a coarse delay amount with an accuracy of a sample time unit for each of the transmit signals and feedback signals and a slight delay amount with an accuracy of a time unit shorter than the sample time unit for each of both signals; and a delay corrector which corrects shifts in timing between the transmit signals and the feedback signals on the basis of the coarse delay amount and the slight delay amount detected by said delay detector.