QUADRATURE MODULATOR, SIGNAL GENERATING DEVICE, AND QUADRATURE MODULATION METHOD

To provide a quadrature modulator, a signal generating device, and a quadrature modulation method capable of correcting a gain balance error, a zero offset error, and an orthogonality error that occur during quadrature modulation. The quadrature modulator 20 includes a quadrature modulation unit 22, a quadrature modulation error calculating unit 40 that calculates quadrature modulation errors on the basis of the power of a quadrature-modulated signal output from the quadrature modulation unit 22, and an error correcting unit 30 that corrects a baseband signal such that the quadrature modulation errors are removed. The quadrature modulation error calculating unit 40 includes a power measuring unit 41 that measures the power of the quadrature-modulated signal, a gain balance error calculating unit 42, a zero offset error calculating unit 43, and an orthogonality error calculating unit 44.