Abstract: A phase-locked loop circuit, having an oscillator controlled by a voltage related to the phase difference between a reference signal and a loop signal, is stabilized by a crystal oscillator. The voltage controlled oscillator signal is frequency-subtracted from the crystal oscillator signal frequency to provide an input signal to a frequency-arithmetic synthesizer which provides a loop signal to the phase detector for comparison with the coming reference signal. Use of a frequency-adder circuit between the voltage controlled oscillator and the frequency-subtractor, and receiving an addition frequency derived from the frequency-arithmetic synthesizing circuit, is utilized to decrease the loop gain and provide enhanced characteristics.