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一、概述在收、发信机间的频率间隔很窄的情况下,即频率间隔是在信道间隔与1—2兆赫之间时,由于接收机的阻塞特性,要求采取必要的预防措施来避免信道上有用信号的减小。这类措施通常包括:收、发天线间必需有足够的空间间隔、馈线和设备和(或)采用适当的射频滤波器减小无用信号,但不要引起信噪比的下降(信噪比的下降是由于接收机前级的反作
I. Overview In the case of very narrow frequency separation between the transmitter and the receiver, that is, when the frequency separation is between 1 and 24 MHz, due to the blocking characteristics of the receiver, the necessary precautions are required to avoid The useful signal on the channel is reduced. Such measures typically include: adequate spacing between the receiving and transmitting antennas, feeders and equipment, and / or the use of appropriate RF filters to reduce unwanted signals, but without causing a degradation of the signal-to-noise ratio Is due to the reaction of the receiver before the level