There are three development for the Middle Power Amplifier : the first stage power amplifier, the drive stage power amplifier and the last stage power amplifier .
本文对固态线性功率放大器的研制包括：前级放大器的研制、驱动级放大器的研制、末级放大器的研制。
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At last, we design an experimental system including signal source, power amplifier array and loudspeaker array. Some experiments of the directive property of loudspeaker array are completed.