Homemade TV Antenna Amplifier, Antenna Amplifier
Keywords: TV antenna amplifier production, UPC1651 antenna amplifier
The antenna amplifier plays a very important role in the wireless TV reception. The weak signal can significantly improve the output level, thereby improving the transaction ratio, making the received TV image more ideal. Antenna amplifier processing method for receiving signals Yes: After zooming in mixing and mixing with mixing and mixing, there is no difference from the word, but only the position of these words is changed. In fact, the antenna amplifier of these two circuits is quite different. In a large number of TV signals and a strong signal, the antenna amplifier mixed after the amplification is significantly better than the antenna amplifier enlarged after mixing. The reason is that the antenna amplifier after mixing is mixed, its amplification integrated circuit is too wide and strong due to working frequency band The weak signal is too large, and it is easy to enter nonlinear state, resulting in a strong signal to interfere with the weak signal. This article gives a circuit diagram of the two amplifiers. The reader can choose one of the circuits according to the channel signal in the region. Work principle: 1. A circuit diagram of an antenna amplifier amplifying the mixed method is shown in Figure 1. The 1 to 12 channel television signal is input in the VHF input, and the L1, C1, L2 form a simple low-pass filter, filter out the TV after the 12 channel. The signal is sent to the IC1 signal input, and the amplification of the amplification of about 20 dB is output, and the amplified television signal is outputted via the capacitance C3. After the L3, C4, the L4 low pass filter is mixed with the UHF signal phase, and transported to the television signal output. Another UHF The 13 ~ 57 channel television signal input is entered, and the simple high-pass filter is composed of C5, L5, and C6, only the 13 channel of the UHF band and the signal of the rear channel, and then add to the IC2 signal input to increase the zoom of about 20 dB, After outputting the high-pass filter (C7, L6, C8) with the VHF television signal. The power supply of the circuit is supplied by the transformer T buck, U1 rectification, C14 filter, IC3 regulating, the amplifier is supplied .LED1, R1 is the power supply indication circuit.
2. Figure 2 is an antenna amplifier circuit diagram of a mixed-amplification method. The principle of working and amplification - the mixed type is similar, and it will not be described here. Component selection: IC1, IC2 Select the wideband TV signal amplification of Japan NEC1651 When the soldering IC1, IC2 requires electric soldering iron to ground or unplug the electric soldering iron power supply to prevent electrostatic damage integrated circuits. Compators for C9, C11, C14 electrolytic capacitance In addition, the remaining use of high-frequency porcelain capacitors. TT selected 220V input, 9V output 3W small power power transformer. U1 1A / 50V circular rectifier bridge, or 4 1 n4001 welding into a bridge rectifier circuit .L1 ~ L4, L7, L8 are used with a ∮ 0.51mm enameled wire around 6 3mm round rod around 2, L9, L10 around 21. The remaining elements can be flexibly selected according to the specification parameters labeled in Figure 1. Due to the work of the antenna amplifier circuit in very high frequency and special high frequency, it is easy to cause high frequency self-excite, so the element pins are shortest possible, especially the pins of IC1, IC2. Circuit board requires high frequency good ring Oxygen resin plate. The circuit should be largely grounded. After the production is good, it can be put into normal use. The component selection shown in Figure 2 is in principle, as in principle, as shown in the antenna amplifier shown in Figure 1. Figure 3 is a high frequency amplification integrated circuit Each foot function and a profile of μPC1651
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