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There is something inside the tuner

Text:[Big][medium][small] time:2018/12/12 10:54:57    Views:    

       What is there in the tuner? The simplest idea is to treat it as a radio receiver. Most of the receiving circuit inside the tuner is arranged in a jog form, and all components are surface mounted.

       The use of micro-motion design is due to its relatively high efficiency in the microwave frequency. The width and length of the fretting are directly related to the frequency of use. The basic function of the tuner is to pick up the weak signal reflected by the dish antenna, and then pass the signal to the receiver. The problem encountered here is that the dish antenna and the receiver are usually separated by a distance, and the loss at the microwave frequency is quite high, in order to overcome the difficulties, the tuner from the dish antenna UHF SHF signal conversion Into a lower IF IF band, and then through the cable to send signals to the receiver, this efficiency is relatively high.

       There are many types of tunes, but their basic designs are similar. The difference is mainly the choice of horizontal or vertical polarization of the signal. The signal is picked up by a micro sensor, and there are three ways to select a horizontal or vertical polarized transmission signal. The easiest way to do this is to install two 90 ° sensors, and to switch back and forth between the output signals they produce, which is the easiest and most widely used method known as horizontal and vertical conversion. Feeder speakers directly connected to the tuner, polarizer installed in the feed speaker and the tuner between the mechanical polarizer has a sensor installed in a waveguide, the waveguide can be rotated, so that the sensor orientation Can be matched with the direction of polarization of the signal, the servo motor controlled by the receiver moves the polarizer as needed, which is the earliest method, but is not reliable.

       Magnetic polarizers are cheaper and more reliable in another way, and there is no moving part. Its role is to change the direction of polarization of the signal before the input signal arrives at a separate sensor. It contains a coil wound around the ferrite core, the coil is driven by the current, the amount of current supplied to determine the curvature of the waveform.


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