n.前级扩大机；前置增幅器
It still is offerred dog the options such as generator and preamplifier. 它还供给跟踪发生器和前置放大器等选件。
The PA7:4 preamplifier is available for J16Quad and J10Quad detectors. 该pa7：4前置供j16quad和j10quad探测器。
The receiver has been designed and made, including preamplifier,amplifier, filter circuit, AGC, PLL, etc. 设计并制作了接收机电路,包括前放电路,放大电路,滤波电路,自动增益控制电路,锁相环电路,判决电路等。
This paper presents an up-to-date design of bioelectric preamplifier with low noise- high common-mode-rejection ratio (CMRR) and high impedance. 本文介绍一种利用负反馈原理由集成运算放大器构成的低噪声、高共模抑制比、高输入阻抚前置放大器。
The key to the design of feeble signal sampling system lies in the designing of ultra low noise preamplifier. 设计超低噪声前置放大器是设计微弱信号采集仪器时不可回避的技术问题。
Main amplifier is used for amplifying the output signal of preamplifier into digital voltage level. 主放大器把前置放大器的输出信号放大到数字逻辑电平,并且保持数字电平的恒定,以实现限幅的功能。
