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CNN has been popular, but because of the limitations of its lines, so that some users are not always high-quality signal, so that TV image signal less than ideal. I use a small amount of components made of a small, easy to use cable TV amplifier. The amplifier has fewer components, circuit simplicity and high efficiency.
How it works: the circuit as shown above. The amplifier and power supply from the amplifier circuit composed of two parts. Amplifier is the core of a Japanese-UHF linear amplifier circuit, outside the production process is the use of microwave device packaging, small size, wide frequency band, amplified effect. Amplified signal from the input capacitor C1, due to the IC's frequency response is good, the gain up to 20dB, the output signal is better. Power supply by the transformer T and high-frequency choke L1 and filter capacitor C7 form. Through 75Ω coaxial cable added to the amplifier output, AC power through the secondary rectifier diode VD2, by C4, R1, C3, and the composition filter regulator circuit VD1, R2 and VD3 light indicator circuit components.
Production Description: circuit, IC model? PC1651. VD1 voltage regulator is 4.9V ~ 5.6V/0.5W, can also be used 2CW53, rectifier VD2 use 1N4001, 2CP16 and so on. VD3 use? 3mm LED can be. In addition to capacitor C3, C4, the remaining high frequency ceramic capacitors are used. Inductor L1 use? 0.5mm enameled wire in? 4mm drill bit dense, respectively, around 20 laps. T use a small power transformers (3W-4W), the secondary voltage of 6V can be. Socket X1, X2 are selected 75Ω coaxial cable outlet.
Amplification of the amplifier and power of two parts should be installed in a shielded box. Shielded box with 0.2-0.3mm thick, made of thin copper or iron shielding box access to a reliable ground should be to get a good shield. Amplifier output, the input impedance of 75Ω, with a high-frequency cable leads from the shielded box. High-frequency cable used SWY-75-5-1-or SS75-5-4 special-purpose cable. Not to use multi-strand wire shielded cable, because it's high-frequency loss, affect the results.
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