| 摘要 |
PURPOSE: To generate the stable frequency almost free from fluctuation and to make possible high-speed lock by switching a correcting voltage to a voltage increasing/decreasing means corresponding to the change of frequency data and the lock state of a frequency concerning a control part. CONSTITUTION: An MPU 61 calculates the voltage to be impressed to a D/A voltages as the correcting voltage, and the calculated voltage is converted into an analog voltage by a D/A converter 63 and inputted to a voltage adder/ subtracter 50. The adder/subtracter 50 correcting the analog D/A voltage from a D/A converter 20 by adding or subtracting it with the analog voltage from the D/A converter 63 and outputs this corrected voltage to a voltage controlled oscillator (VCO) 30 as the D/A voltage. Then, the VCO 30 inputs this corrected D/A voltage and generates the high frequency signal of a frequency corresponding to its voltage value. In this case, one part of this output is inputted to a phase locked loop circuit PLL 40 and compared with a reference frequency, a PD voltage is outputted to provide a target frequency, and the VCO 30 is controlled. |
