An apparatus includes a test signal generation unit supplying test signals to an orthogonal modulator and a control unit that based on a result of decision by comparison and decision of detection results of a detector detecting envelopes of modulated signals output from the orthogonal modulator responsive to the test signals, derives adjustment values and a compensation value. An estimation means estimates a DC offset and an IQ mismatch of the orthogonal modulator, based on the derived compensation value. The test signals includes a first set including a first test signal (I1, Q1) and a second test signal (I2, Q2) having a predetermined relationship with the first test signal, and a second set of which in-phase and quadrature components have predetermined relationships respectively with in-phase and quadrature components of the first set.