| 摘要 |
PURPOSE:To obtain an oscillation and modulation circuit having flat frequency characteristics in modulation sensitivity, by connecting an element of a minute capacitance between input terminals of a varactor element and an active element as a part of an oscillation element connected to a modulation signal source and a bias source. CONSTITUTION:A circuit taking a transistor (TR)3, and a crystal oscillator 4 as major elements is oscillated in a radio frequency. A modulation signal is applied from an input terminal 1 via a coupling capacitor (C)5. A bias voltage is applied to a varactor diode 2 via a bias resistor (R)18 from a bias power supply terminal 17. A C16 having a minute capacitance is connected between a connecting point A with the C5, the R18 and the diode 2 and an input terminal 20 of the TR3. In this case, the C16 and the input resistor of the TR3 form a pass region for radio frequencies and a block region for the modulation frequency. Thus, a crystal oscillation modulation circuit having a flat frequency characteristic in the modulation sensitivity is obtained and used for high speed data transmission also. |
