| 摘要 |
PROBLEM TO BE SOLVED: To keep transmission quality high over a wide dynamic range, in relation to a transmission power controller that controls the level of a transmission wave at a transmitting end of a radio transmission system and to a transmitter in which the transmission power controller is loaded. SOLUTION: This transmission power controller comprises a first amplification means that amplifies a modulated wave and outputs an intermediate frequency signal, a frequency conversion means that converts the frequency of the intermediate frequency signal to generate a radio frequency signal, a second amplification means that amplifies the radio frequency signal to generate a transmission wave and feeds the transmission wave to an antenna system, and a control means that maintains the combination of the gains of the first amplification means and the second amplification means so that the level of the transmission wave that arrives at a receiving end which receives the transmission wave takes a specified value and that maintains the gain of the first amplification means so that the SN ratio of the intermediate frequency signal which is outputted from the first amplification means takes a value which is more than a desired lower-limit value under the level of the transmission wave.
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