To provide an amplifier which attains high gain by preventing a gain from being deteriorated by the distribution loss of an input distributor in a high-efficiency Doherty amplifier, and is capable of reducing high-order distortion by suppressing an increase in the high-order distortion.
Outputs from a carrier amplifier circuit 4 which operates in a class-AB and a peak amplifier circuit 5 which operates in a class-B or C class are combined at a node 62 and output. The length of a transmission line 33 is adjusted for a signal distributed by a distributor 2, a reflection coefficient in low input is changed, impedance conversion is applied to a signal from the carrier amplifier circuit 4 by an impedance converter 64 and regarding a signal from the peak amplifier circuit 5, impedance in low input is made large so as not to cause a loss on a transmission line 65. During the low input, input impedance at a side of the peak amplifier circuit 5 from the distributor 2 is made closer to infinity, so that the amplifier increases a gain during low input.
| JPH06152279 | TRANSMISSION POWER AMPLIFIER |
| JPH06204765 | POWER SYNTHESIS DEVICE |
TAKEDA YASUHIRO
NAKAMURA MANABU
MOTOE NAOKI
Kiyotaka Sakamoto
Next Patent: TRANSMISSION METHOD, RECEPTION METHOD AND TRANSMITTER AND RECEIVER UTILIZING THEM