| 摘要 |
PURPOSE:To change an oscillating frequency over a wide range stably, by forming a variable capacitor section with a pair of differentially connected transistor (TR) and attaining circuit integration easily. CONSTITUTION:An oscillating circuit consists of a positive feedback amplifier section 1, an oscillating element 9 and the variable capacitor section 10. The positive feedback amplifier section 1 is formed mainly with the differentially connected TRs 2, 3 and a constant current source 4. The section 10 is mainly formed with differentially connected TRs 11, 12, a current source 13, a capacitor 14 and a resistor 15. Since the positive feedback amplifier section and the variable capacitor section are formed in a single integrated circuit, the circuit integration is attained easily. Since the capacitance of the variable capacitor section is changed with the change in the current of the source 13, the oscillating frequency is changed over a wide range stably. |
