Think about buying an aerial with a built-in signal amplifier, especially if the television set is more than 20 feet (six metres) away.
特别是如果电视机与天线距离超过超过20英寸(6米)，就得考虑买一个内置信号放大器的天线。
2
In the television system, the head amplifier, whose low noise being put the first place in all the features, is one of the most important element circuits, which determines the image quality.