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一、高频头的作用、组成及类别高频头是低噪声放大器和下变频器的合称,英文缩写为LNB,它的作用是对馈源收集送来的电磁波进行低噪声放大,并与本机振荡信号进行混频得到950~1750 MHz的降频信号,我们称此降频信号为笫一中频信号,该信号由高频头的前置中频放大器放大后,通过电缆线传送给室内单元。高频头的组成方框图如图1所示,它由波导微带转换头、低噪声场效应
First, the role of high-frequency head, composition and category Loudspeaker is a combination of low-noise amplifier and down-converter, the abbreviation for the LNB, its role is to feed the collected electromagnetic waves sent to low-noise amplification, and The local oscillation signal to be mixed to get the frequency of 950 ~ 1750 MHz signal, we call this down signal Zi Zi IF signal, the signal from the front of the tuner IF amplifier amplified by cable to the indoor unit . The composition of the high-frequency head block diagram shown in Figure 1, which consists of waveguide microstrip conversion head, low noise field effect