PURPOSE: To obtain the wide-capture range and high-stability phase locked loop(PLL) controller with simple circuit configuration by controlling the self- traveling frequency of a variable frequency oscillating means based on the outputs of a storing means and of a phase comparing means.
CONSTITUTION: In PLL control, a frequency to be inputted to capture range is not searched but the change of an error voltage when starting the cap- challenge is discriminated by a means 14 to discriminate the change in the error voltage of the PLL. On the other hand, the storing means is provided to store the self-traveling oscillation frequency (free oscillation frequency) of a variable frequency transmitter (VCO) 9, and a means 15 is provided to vary the free oscillation frequency of the VCO. Thus, the stable PLL control can be obtained while preventing circuit scale from being sharply enlarged.
KAWASAKI MOTOAKI
MIZUNO HIROYUKI
