| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve oscillation purity by connecting a coil and a capacitor in series to each other and inserting a circuit connected in series to a capacitor to a circuit connected in parallel to a coil between the collector and base terminals of a high frequency transistor. SOLUTION: A capacitor C5 is connected to the base terminal of an oscillation transistor Q1 via the serial connection capacity of a variable capacity diode D1 connected in parallel to the C5 and a capacitor C6, an inductor L1 connected in parallel to an inductor L2 connected in series to the serial connection capacity, and a capacitor C4 respectively. The D1 changes the oscillation frequency by the capacitance change due to the DC voltage applied to a terminal P2 via a resistor R5. Then a circuit consisting of two capacitors which show the inductance characteristic in only an extremely narrow frequency range and two coils is inserted and connected between the collector and base terminals. In such a constitution, an oscillation circuit is obtained with excellent frequency selection degree characteristic that is secured by the collector-emitter terminal capacitance.</p> |
