To prevent spurious radiation of a pilot signal by changing setting of a frequency of a pilot signal, in response to a control state of a distortion eliminating loop and to relax a required characteristic of a band block filter and an auxiliary amplifier which is the requirement of the prevention above.

When the control by the distortion-eliminating loop does not converge, the frequency of the pilot signal is set to a frequency apart from a frequency band of an input signal. When the control of the distortion eliminating loop converges, the frequency of the pilot signal is set to a frequency in the vicinity of the frequency band of the input signal.