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一、概述: 光导摄象管前置放大器是用电视监视器把光导摄象管输出的微小图象信号放大到足够显象的地步,并且具有足够带宽的放大电路。因为输入信号很小(约0.2～0.3微安P—P),所以,图象信号的信噪比(s/N)就成为首要的问题,它主要由第一级所使用的元件的噪声指数来决定。为了构成这种前置放大器,在这里我们首先对几种不同类型的放大器进行一下比较,如表1所示。从表1可以看出,根据信噪比(s/N),传输特性(线性畸变)、及温度特性等主要评价指标,很明显,低输入阻抗形式,并附有噪声抑制电路的那种放大器为最好。关于这类放大器的元件参数计算,及整体电路的设计,
I. Overview: Light guide tube preamplifier is the TV monitor to the light guide tube output of the tiny image signal amplification enough to the point of imaging, and has enough bandwidth amplification circuit. Since the input signal is small (about 0.2 to 0.3 μA P-P), the signal-to-noise ratio (s / N) of the image signal becomes the primary issue which is mainly caused by the noise figure of the components used in the first stage To decide. In order to constitute this preamplifier, here we first compare several different types of amplifiers, as shown in Table 1. It can be seen from Table 1 that according to the main evaluation indexes such as signal to noise ratio (s / N), transmission characteristic (linear distortion) and temperature characteristic, it is clear that the low input impedance type amplifier with noise suppression circuit For the best. About this type of amplifier component parameter calculation, and the overall circuit design,