| 摘要 |
PURPOSE: A circuit for generating a control signal of a voltage controlled oscillator is provided, which prevent a mis-operation of the voltage controlled oscillator beforehand by supplying a voltage more accurately and stably at all periods of a sawtooth wave whose period is varied. CONSTITUTION: A D/A(Digital/Analog) converter(11) converts a digital signal into an analog voltage, and the first switch(12) adjusts the analog voltage from the D/A converter again. An integrator(13) integrates voltages from the first switch, and a comparator(14) compares an output of the integrator with a comparison voltage. And the second switch(15) bypasses a voltage inputted to an RC circuit by generating a control signal when the output voltage exceeds the comparison voltage in the comparator. A number of resistors(R1,R2,R3) are installed in the first switch and a control line is connected to the first switch. And a capacitor(C) is installed in the integrator and forms the RC circuit together with the resistors.
|
