Distortion compensating apparatus and method

A distortion compensating method for compensating for nonlinearity of an amplifier by quadrature-modulating an input signal before inputting the input signal to the amplifier and by adaptively updating a distortion compensation coefficient for the input signal based on a difference between the input signal and an output signal of the amplifier, said method comprising the steps of:

• (a) detecting the amount of distortion of an output signal of the amplifier;
• (b) correcting a parameter held in a parameter holding means, which is capable of varying the difference according to the parameter set therein, in such a manner that the distortion amount detected at said step (a) is improved;
• (c) detecting a noise component that can be caused in the output signal resulting from the quadrature-modulation;
• and
• (d) performing processing for removing the noise component detected on said step (c).

A distortion compensating method for compensating for nonlinearity of an amplifier by quadrature-modulating an input signal before inputting the input signal to the amplifier and by adaptively updating a distortion compensation coefficient for the input signal based on a difference between the input signal and an output signal of the amplifier, said distortion compensating method comprising:

• detecting the amount of distortion of an output signal of the amplifier;
• correcting a parameter held in a parameter holding part, which is capable of varying the difference according to the parameter set therein, in such a manner that the distortion amount is improved;
• detecting a noise component that can be caused in the output signal resulting from the quadrature-modulation;
• and
• performing processing for removing the noise component.