Distortion compensator

A predistortion type distortion-compensated amplifier having a distortion compensator that compensates for distortion arising in an amplifier that amplifies a signal, wherein:

• the predistortion type distortion-compensated amplifier comprises:
• signal change means that changes the amplitude or phase or both of the signal subject to amplification by the amplifier,
• signal level detection means that detects the level of the signal subject to amplification by the amplifier,
• signal level change direction detection means that detects whether the direction of change in the level of the signal subject to amplification by the amplifier is the positive direction or the negative direction, and
• signal change control means that stores the correspondence between the signal level and a mode of changing the signal for distortion compensation in the case that the direction of change in the signal level is the positive direction, and also stores the correspondence between the signal level and the mode of changing the signal for distortion compensation in the case that the direction of change in the signal level is the negative direction, and based on the content thus stored, controls the signal change means such that it changes the signal subject to amplification by the amplifier in the mode of changing the signal corresponding to the direction of change in the signal level detected by the signal level change direction detection means and the signal level detected by the signal level detection means.

A communication station unit of a mobile communications system having a distortion compensator that compensates for distortion arising in an amplifier that amplifies a signal to be sent, wherein:

• the communication station unit of the mobile communications system comprises:
• signal change means that changes the amplitude or phase or both of the signal subject to amplification by the amplifier,
• signal level detection means that detects the level of the signal subject to amplification by the amplifier,
• signal level change direction detection means that detects whether the direction of change in the level of the signal subject to amplification by the amplifier is the positive direction or the negative direction, and
• signal change control means that stores the correspondence between the signal level and a mode of changing the signal for distortion compensation in the case that the direction of change in the signal level is the positive direction, and also stores the correspondence between the signal level and the mode of changing the signal for distortion compensation in the case that the direction of change in the signal level is the negative direction, and based on the content thus stored, controls the signal change means such that it changes the signal subject to amplification by the amplifier in the mode of changing the signal corresponding to the direction of change in the signal level detected by the signal level change direction detection means and the signal level detected by the signal level detection means.

A distortion compensator that compensates for distortion arising in an amplifier that amplifies a signal, wherein:

• the distortion compensator comprises:
• signal change means that changes the amplitude or phase or both of the signal subject to amplification by the amplifier,
• signal level detection means that detects the level of the signal subject to amplification by the amplifier,
• signal change control means that stores the correspondence between the signal level and a mode of changing the signal for distortion compensation, and based on the content thus stored, controls the signal change means such that it changes the signal subject to amplification by the amplifier in a mode of changing the signal corresponding to the signal level detected by the signal level detection means, and
• a signal change control content updating means that updates the content of the correspondence between the signal level and mode of changing the signal for distortion compensation stored by the signal level change control means so that the distortion contained in the signal after being amplified by the amplifier is reduced, and where
• the timing of signals processed by the signal change means is asynchronous from the timing of controlling the signal change means based on the level of this signal by the signal change control means.

A predistortion type distortion-compensated amplifier having a distortion compensator that compensates for distortion arising in an amplifier that amplifies a signal, wherein:

• the predistortion type distortion-compensated amplifier comprises:
• signal change means that changes the amplitude or phase or both of the signal subject to amplification by the amplifier,
• signal level detection means that detects the level of the signal subject to amplification by the amplifier,
• signal change control means that stores the correspondence between the signal level and a mode of changing the signal for distortion compensation, and based on the content thus stored, controls the signal change means such that it changes the signal subject to amplification by the amplifier in the mode of changing the signal corresponding to the signal level detected by the signal level detection means, and
• a signal change control content updating means that updates the content of the correspondence between the signal level and mode of changing the signal for distortion compensation stored by the signal level change control means so that the distortion contained in the signal after being amplified by the amplifier is reduced, and where
• the timing of signals processed by the signal change means is asynchronous from the timing of controlling the signal change means based on the level of this signal by the signal change control means.

A communication station unit of a mobile communications system having a distortion compensator that compensates for distortion arising in an amplifier that amplifies a signal to be sent, wherein:

• the communication station unit of the mobile communications system comprises:
• signal change means that changes the amplitude or phase or both of the signal subject to amplification by the amplifier,
• signal level detection means that detects the level of the signal subject to amplification by the amplifier,
• signal change control means that stores the correspondence between the signal level and a mode of changing the signal for distortion compensation, and based on the content thus stored, controls the signal change means such that it changes the signal subject to amplification by the amplifier in the mode of changing the signal corresponding to the signal level detected by the signal level detection means, and
• a signal change control content updating means that updates the content of the correspondence between the signal level and mode of changing the signal for distortion compensation stored by the signal level change control means so that the distortion contained in the signal after being amplified by the amplifier is reduced, and where
• the timing of signals processed by the signal change means is asynchronous from the timing of controlling the signal change means based on the level of this signal by the signal change control means.