Home satellite TV and cable TV common cable transmission and remote control circuit

Families usually can only watch satellite TV on the TV set next to the satellite receiver, but it is more difficult to watch in other rooms. I used the original indoor cable TV lines to mix satellite TV signals and cable TV signals and transmit them on the same cable, realizing my wish that all TV sets in the whole family can watch satellite TV. The common cable transmission connection circuit is shown in Figure 1. The U-segment satellite TV signal output from the RF output end of the satellite receiver is first amplified by the transistor VT1, and the amplified signal is then mixed with the cable TV signal entering the home through the 75-3 feeder. C5, L4, and C6 form a simple high-pass filter to prevent cable TV signals below 470MHz from entering the 75-3 feeder and reduce signal loss. The function of L6 is also to reduce the cable TV U-segment signal loss. The mixed signal is amplified by the VT2 amplifier tube, and finally distributed and output to each indoor user box by the distribution core coil T2. The DC working power supply of the VT1 and VT2 signal amplification circuits is provided by the AC 220V mains power after being stepped down by the transformer T1, rectified by a bridge composed of diodes D1~D4, and filtered by the capacitors C1 and C2. Component selection: VT1, VT2 selects 2SC3355 ultra -high -frequency low noise magnifying triode; T1 selects small power transformers with a power of about 2VA and an output voltage of about 12V, L1 ～ L6 uses ∮ 0.51mm paint wiring on the bead pen, and the bits are densely reborn. L1, L2, L3, and L5 are wound with 10 turns, and L4 and L6 are wound with 3 turns; except for C1, which uses an electrolytic capacitor, the other capacitors use high-frequency ceramic capacitors; T2 uses the distribution core coil in the cable TV distributor, please note Don’t make mistakes with the input, output and ground wires. Generally, the output terminal is connected to both ends of the resistor R. Other component parameters are marked in the figure. The outer shell can be a distributor aluminum shell, one installed indoors and outdoors. The wiring connection of remote remote control is shown in Figure 2. Three lines (remote control signal, ground, +5V) are connected in parallel to the infrared receiver in the satellite receiver, and connected to the infrared receiver in a remote location through a two-core shielded wire. The normal operating voltage range of the infrared receiver is 4.5V ~ 5.5V, so the number of parallel connections should not exceed two, otherwise the operating voltage will be too low (less than 4.5V) and it will not work properly. In addition, the two-core shielded wire connecting the infrared receiver should not exceed 30 meters, otherwise the remote control signal will be attenuated too much and cause the satellite receiver to operate incorrectly or malfunction. The appearance and pin functions of two common sizes of infrared receivers are shown in Figure 3.