| 摘要 |
<p>An antenna amplifier and an antenna device on the top of the car are provided. The antenna amplifier includes an AM frequency selection circuit, an AM signal amplifier circuit, a FM frequency selection circuit, a FM signal amplifier circuit and a power circuit. In which, said antenna amplifier also includes a wave trapper circuit, of which one end is connected to the ground end of the antenna amplifier and the other end is connected to the antenna metal mounting bottom board on the top of the car. The antenna device includes a shark fin type antenna shell, a metal mounting bottom board, an antenna support, and a radio receiving antenna. Saidantenna shell is mounted on the metal mounting bottom board to form an inside accommodation space. The antenna support, the radio receiving antenna and the circuit board with the antenna amplifier are arranged in the accommodation space. The ground electric potential of the antenna amplifier on the printed circuit board is raised as the height of the antenna amplifier with respect to the metal mounting bottom board is raised in the invention, so the absorption of the high frequency signal of the top of the car is reduced and the receiving effect of the amplifier is enhanced.</p> |
