| 摘要 |
PURPOSE:To obtain a frequency modulating circuit which has a wide range of frequency and a large modulation factor, by connecting an inductance between a crystal oscillator and a modulated input terminal for a series circuit of a crystal oscillator and a varicap diode. CONSTITUTION:A crystal oscillating circuit of FM modulation contains a crystal oscillator 1 connected with a varicap diode 2 which varies by voltage variations. An inductance 3 is connected between the oscillator 1 and a modulated signal input point A. Inductance 3 has a function to weaken the modulated signal of a rectangular wave supplied from a crime prevention center, etc. at the point A. Thus the distortion is reduced for the FM-modulated output, and at the same time the band of modulation is increased. |
