| 摘要 |
<p>A temperature compensated oscillator comprises a voltage controlled oscillation circuit (28) for generating an oscillation output signal whose frequency changes according an applied control voltage (Vc1, Vc2); a temperature compensation circuit (21) for outputting a temperature compensation voltage (Vc1) for keeping said frequency constant irrespective of temperature changes; and filter means (23) for removing noise contained in the temperature compensation voltage (Vc1). Power control means (26) is provided for controlling the power supply to said voltage controlled oscillation circuit (28) and said temperature compensation circuit (21). Switching means is responsive to the power control means (26) starting to supply power to said voltage controlled oscillation circuit (28) for temporarily switching, for a specified period, from a first state to a second state, said switching means (SW1), in said second state, changing the characteristic of said filter means (23) such that the signal delay caused by said filter means is substantially smaller than it is in the first state of said switching means. In this way phase noise of the output signal from the oscillator can be reduced and the frequency of the output signal stabilizes within a short time without the response a frequency control becoming affected. <IMAGE></p> |
