Quadrature demodulator, quadrature demodulating method and recording medium thereof

Application Number: 00107771
Application Date: 2000.05.23
Publication Number: 1275012
Publication Date: 2000.11.29
Priority Information: 2000/3/14 JP 069703/2000; 2000/4/14 JP 113409/2000; 1999/5/24 JP 143512/1999
International: H04L27/00;H03D1/00
Applicant(s) Name: Advantest Corp.
Inventor(s) Name: Kato Takashi
Patent Agency Code: 11234
Patent Agent: wan huatang
Abstract A quadrature demodulator capable of calibrating an I (Q) signal conversion section without stopping the receiving operation performed by the quadrature demodulator. The quadrature demodulator comprises: an adder for generating a pseudo noise superimposed signal obtained by adding a user signal IF and a pseudo noise PN; a signal conversion section 100 for generating a converted signal obtained by mixing the pseudo noise superimposed signal with a local frequency signal L1 of a predetermined local frequency; a first multiplier 72 for generating a correlated signal obtained by multiplying the converted signal with the pseudo noise, a first integrator 82 for integrating the correlated signal to provide an output; and a succeeding circuit 90 for processing the converted signal in a desired way. While performing calibration by causing the first multiplier 72 to extract the pseudo noise, the quadrature demodulator allows the succeeding circuit 90 to process the converted signal in a desired way. Therefore, the quadrature demodulator can calibrate the signal conversion section 100 without stopping its own receiving operation.