| 摘要 |
PROBLEM TO BE SOLVED: To provide an amplification circuit capable of achieving high linearity without being affected by variance in manufacturing transistors. SOLUTION: DC voltages VinA, VinB at two points are given to an input of the amplification circuit, outputs VoutA, VoutB thereof are held by a sample/hold circuit SH1/SH2, and operation to derive a coefficient (q) based on the values is performed by an operational circuit AMP1, and operational results are compared with the last operational results held in a sample/hold circuit SH4 by a comparator circuit CMP1 and when the operational results of the operational circuit AMP1 are smaller than the last operational results, a bias control circuit BC1 reduces a bias current ratio (m). Thus, the coefficient (q) of the bias current ratio least reducing third-order distortion of the amplification circuit is determined by itself and high-linearity amplifying operation is performed by the optimum bias current. COPYRIGHT: (C)2008,JPO&INPIT
|
