Band selection type feed forward amplifier

A band selection type feed forward amplifier, having a distortion detection circuit and a distortion elimination circuit,

• wherein
• said distortion detection circuit comprises:
• a first linear signal path constituted by a first delay means;
• a first vector adjustment path;
• a first dividing part distributing an input signal to said first linear signal path and said first vector adjustment path;
• n first vector adjusters provided in said first vector adjustment path and adjusting the phase and amplitude of signals in respectively different frequency bands;
• a first switching means selecting one from among said n first vector adjusters and inserting the same into said first vector adjustment path;
• a first multiple frequency band amplifier amplifying the output of said first vector adjusters;
• and
• a combiner/divider respectively outputting the additive component and the differential component of the output of said first linear signal path and the output of said first multiple frequency band amplifier;
• wherein
• said distortion elimination circuit comprises:
• a second linear signal path, constituted by a second delay means, into which said additive component is input;
• a second vector adjustment path into which said differential component is input;
• n second vector adjusters, provided in said second vector adjustment path and respectively adjusting the phase and amplitude of the signals in the same frequency bands as in said n first vector adjusters;
• a second switching means selecting one from among said n second vector adjusters and inserting the same into said second vector adjustment path;
• a second multiple frequency band amplifier amplifying the output of said second vector adjusters;
• and
• a second combining part combining and outputting the output of said second linear signal path and the output of said second multiple frequency band amplifier;
• N being an integer equal to or greater than 2;
• and comprising:
• a frequency controlling part switching and controlling said first switching means and said second switching means.