| 摘要 |
PURPOSE:To smooth change in an output ranging from a low output to a high output, by providing a variable attenuator at the input stage of a unit power amplifier constituting a device, and also providing an output level detecting means at the output stage, and controlling the attenuator corresponding to a difference between the output level of the detecting means and the output of a reference voltage generator. CONSTITUTION:A high frequency output from a driving part 1 is sent to a power distributor 2, and it is distributed to uniform outputs, and they are sent to plural uniform power output parts 30 in a power parallel amplifier means 3 respectively. Also, a reference voltage from a reference voltage generating part 100 is impressed on the output part 30, and the outputs of the amplifier means 3 are synthesized at a power synthesizer 4, and it is outputted to a load 7 via an isolator 5, a directional coupler 6. In such a way, the output part 30 consists of a unit amplifier 31, a voltage variable attenuator 32 connected to the input stage of the amplifier, an output level detection monitoring circuit 33 connected to the output stage of the amplifier, and a loop control circuit 35, and the reference signal of the generator 100 is compared with the output signal of the circuit 33, and the attenuator 32 is controlled corresponding to the size of the difference.
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