Operational amplifier is the most versatile signal conditioning block in any portable system. It can be a filter, an amplifier, an voltage detector, a level shifter, a buffer or even a switch.

对于便携式电子产品来说，运算放大器可算是万能的信号调节电路，因为它可以执行滤波器、放大器、电压感测器、电平移位器、缓冲器、甚至开关等多种不同功能。

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The amplifier proposed in this thesis is designed for portable equipment.

该放大器主要应用在便携式移动设备领域。

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Case in point: the Icon iDo integrated digital-to-analog converter (also called a DAC) and integrated amplifier is geared specifically toward Apple portable devices like the iPhone and iPad.

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