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问:由分立元件组成的通话电路可分为几类? 答:按放大器级间耦合的方式分有两类:一类是阻容耦合式,另一类是直接耦合式。 问:阻容耦合式通话电路有何特点? 答:这类通话电路中的放大器,各级的直流工作点相互独立,调定方便。但是,由于音频信号需经电容耦合至下一级,其低频部分就会产生较大的容抗衰减。因此,现在的电话机通话电路采用阻容耦合方式的只是一少部分。 问:能否就一具体的阻容耦合式送话电路予以介绍? 答:如图1所示。送话电路由VT_4、CT_5两级放大器
Q: The circuit composed of discrete components can be divided into several categories? A: According to the way the amplifier stage coupling there are two types: one is RC-coupled, the other is direct coupling. Q: What are the characteristics of RC-type communication circuit? A: The amplifiers in this type of communication circuit, DC operating point at all levels are independent of each other, easy to set. However, since the audio signal needs to be capacitively coupled to the next stage, its low-frequency part will have a larger capacitance attenuation. Therefore, the present telephone communication circuit using RC coupling is only a small part. Q: Can I introduce a specific RC-coupled transmission circuit? A: As shown in Figure 1. Send circuit by VT_4, CT_5 two-stage amplifier