| 摘要 |
PURPOSE:To obtain a frequency output signal with excellent temperature characteristics, by providing a voltage controlled oscillator for reference frequency generation, summing the outputs of the voltage controlled oscillator and picking up the beat component. CONSTITUTION:A difference of oscillating frequencies of voltage controlled oscillators 2 and 4 when a control voltage on a signal line 11 is minimized, is taken so as to obtain the minimum frequency of a desired output of a signal line 17, and when this control voltage is maximum, the difference of said frequencies is taken as the maximum frequency. An output signal line 16 of an addition circuit 6 has frequency components of f1+f2 and ¦f1-f2¦, where f1 is a frequency on a signal line 13 and f2 is that on a signal line 15. The (f1+f2) is cut off at a rectifying circuit and an LPE7 and the ¦f1-f2¦ frequency component only is obtained on the line 17. That is, the frequency output controlled with the voltage can be obtained. Since components of similar characteristics are used for the oscillators 2 and 4, the effect of temperature change can be suppressed lower. |
