Keywords: satellite TV
The method of separating the different programs of the Satellite TV is not very complicated, but it is more professional. The following is from the < Electronic Newspaper. No. 49 3. No. 49 3. 1881. Satellite TV Branch Review Practice. Be
First, from several circuit diagrams of this article, the device connection is too complicated. Due to the more devices, and mostly passive devices, the insertion loss is large, and the white white has lowered the satellite TV. And this line signal is not unknown, so it is easy to cause a failure of the program. In the case of the satellite TV down signal, two satellite TV signal amplifiers are added. It is estimated that the output level of the first amplifier has been greatly higher than the threshold level of the second amplifier, causing such low noise high sensitivity. The amplifier is amplified, and the magnification is not enlarged, so the signal is not received. Several procedures can reach the purpose of the satellite TV. Be
First, 105.5 ° E ~ [176.5 ° E Satellite TV signal is received as an example, and the wiring diagram is shown in Figure 1. In Fig. 1, after the two antennas are collected by a 75-5 TV cable, a satellite television two-power dispenser is used as a mixer, and the signal received by the two antennas is mixed. The method is: the input and output port of the secondary divider, the output port as the input port of the two signal, and the input port as the output port of the mixed signal. In essence, the satellite TV power distributor is the same principle as the cable TV distributor, which is only the upper and lower limit frequencies are much higher than the cable TV distributor, and it is entirely possible as a satellite TV signal broadband mixer. This avoids switching signals with Satellite TV switches. After mixing Satellite TV signals, access a satellite TV two-shifter, all the way to the room, and enter the room 2, each connected the satellite television receiver, the satellite TV signal received by the satellite TV receiver is demodulated Output for video signal V and audio signal A, this AV signal is re-entered into the TV AV input port for television viewing. For cable sources, the cable TV signal is divided into two channels with a cable TV dies, and enter the room one and the room. Insert the TV RF signal RF entry for receiving cable television signals. In this way, the satellite television receiver can be used to view different satellite TV programs in different rooms, and there is also a cable TV program. Be
The disadvantage of this is: 1. With two satellite TV power, the insertion loss is large. If the TV signal is weak, you have to install a satellite TV antenna amplifier. In the figure, there are two antenna amplifiers that have a dashed frame in the figure, the strong installation of the response signal, and the installed place is also dependent on the situation (in a weak section of the signal). 2. When receiving two signals, the TV is to perform AV or RF conversion, cumbersome. 3. It is possible that the downlink signal received by the two-sided satellite TV antennas has a little interference with two signals adjacent to the two-way frequency, but this phenomenon is very small.
Second, with a satellite TV antenna as an example, introduce a method of television reception using a radio frequency signal RF mode.
As shown in Figure 2, the downlink signal received by the satellite TV antenna is divided into two channels via the second-actuer, and the room is entered into the satellite television receiver. In general, the satellite TV receiver has a radio RF output port. In this way, the radio frequency signal output from the satellite television receiver is mixed with a wired television dies as a mixer with a wired TV di-dispenser with a wired TV dies. Since the radio frequency frequency of the general satellite receiver is less than 22ch, it is impossible to cause interference to the cable TV signal, and the bandwidth of the cable TV dies is 5 MHz-1000 MHz, and the two signals can be mixed. If such a process is demodulated, there is interference, and there is a radio frequency modulation of the TV signal received by the satellite television receiver according to the method of FIG. The modulator should select the adjacent frequent frequency conversion, select cable TV vacant channel frequency output, and enter the television radio RF entry end for the television audio RF entry end after mixing cable television signals. If the adjacent frequency frequency conversion modulator cost is too high, it is possible to use a tuning recorder that is not aware of a tuning recorder, and the radio frequency output of the recorder is adjustable, and the mutual interference can be effectively avoided.
When connecting, the trace of the TV cable should be shortened to reduce the loss of the cable to the signal. And the cable should be well used to ensure the matching of 75Ω. The passive device is also 75Ω matching impedance, and the reflected loss should be greater than 16 dB to reduce the standing wave strength formed by the reflection wave to avoid the occurrence of ghosting.
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