| 摘要 |
PURPOSE:To regenerate a sound with less noise and less interference, by varying only the amplification band of a narrow-band antenna amplifier according to the turning frequency of a receiver. CONSTITUTION:An antenna amplifier 21 amplifies a radio wave received by a hot wire 2 fitted to rearwindow glass 1 or an FM antenna wire 5, and consists of a variable narrow-band filter circuit 22 and an amplifier 23. This circuit 22 has narrow-band frequency characteristics, and its frequency characteristics of the center frequency of the narrow band width vary with the tuning frequency of a receiver by a tuning signal supplied from the receiver 9 through a wire 24. Consequently, a signal having a frequency close to a reception frequency is not amplified by the antenna, so the receiver regenerates a sound with less noise and less interference. |
