Patent ID: 7509106
Filing Date: 2009-03-24
Classification: H04B

Abstract:
1. A test signal generation circuit comprising: a tuning circuit for picking up a reception signal having a predetermined frequency; a local oscillation circuit for forming a pair of orthogonal local oscillation signals; a pair of first mixer circuits for frequency-converting the reception signal into a pair of intermediate frequency signals by using the pair of orthogonal local oscillation signals; a pair of intermediate frequency filters for extracting the pair of intermediate frequency signals from output signals of the pair of first mixer circuits; a pair of phase shift circuits for shifting phases of the pair of intermediate frequency signals extracted by the pair of intermediate frequency filters; a first calculation circuit for outputting an intermediate frequency signal through addition or subtraction of output signals of the pair of phase shift circuits; a signal forming circuit for forming a pair of orthogonal alternate current signals having a frequency equal to an intermediate frequency of the pair of intermediate frequency signals; a pair of second mixer circuits for receiving the pair of orthogonal alternate current signals and the pair of orthogonal local oscillation signals; and a second calculation circuit for outputting a signal having a predetermined frequency of an image frequency by addition or subtraction of outputs of the pair of second mixer circuits, wherein an output signal of the second calculation circuit is supplied to the tuning circuit as a test signal.