| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable gain amplifier circuit the DC voltage of the output of which is unchanged even when a gain and a temperature are changed and to provide a transmission apparatus and a reception apparatus including such a variable gain amplifier circuit. SOLUTION: Current control sections 202A, 202B respectively change currents I1, I2 in accordance with a control voltage V1 to determine the gain. Current correction sections 204A, 204B respectively change currents I1A, I2A in accordance with the control voltage V1 in such a way that DC components of currents flowing through resistors R1, R2 are constant independently of the gain. The current control section 202A and the current correction section 204A respectively change the currents I1, I1A to cancel a temperature change in the resistor R1 and the current control section 202B and the current correction section 204B respectively change the currents I2, I2A to cancel a temperature change in the resistor R2. Thus, the DC component of the output voltage is made constant independently of the temperature. COPYRIGHT: (C)2006,JPO&NCIPI
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