| 摘要 |
PURPOSE:To decrease the entire shape by connecting a coil for a band-pass filter between a DC power supply of an automobile and a heater wire so as to use the stray capacitance and the band-pass filter coil between the heater wire and ground as a part of an input band-pass filter to the compensation amplifier. CONSTITUTION:A band-pass filter coil La1 for AM wave, a cancel coil Lc canceling the DC magnetization by the coil La1 and a coil Lf1 for band-pass filter for FM wave are provided between the heater wire H and a battery B. A power noise rejection through-capacitor C is provided between the cancel coil Lc and the battery B. Moreover, a stray capacitor Cs is a capacitor between the heater wire H and ground. The band-pass filter coil Lf1 and the stray capacitor Cs are used as a part of the input band-pass filter of the compensation amplifier of FM wave band. Thus, the entire shape is decreased.
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