Abstract: A phase compensation circuit for use in an automatic control system is disclosed. An input terminal is connected via a first adder, a signal line and a second adder to an output terminal, a series circuit of a variable resistor and a capacitor is connected between the signal line and ground potential, a voltage at a junction between the resistor and capacitor is fed back to the first adder via a first active circuit having an amplification of (1-.beta.) and fed forward to the second adder via a second active circuit having an amplification of (.alpha.-1). When the amplifications (1-.beta.) and (.alpha.-1) of the first and second active circuits are adjusted under the condition of .alpha..beta.=1, a phase angle of a phase-frequency characteristic at a center frequency can be directly controlled, and when the variable resistor is adjusted, the center frequency can be controlled independently from the phase angle.

Abstract: In a frequency characteristic adjusting circuit having an arrangement of at least one adder, a filter circuit and feedback and/or feed forward means the transfer factors of which and the peak or dip of the filter circuit are freely selectable. Adjustment of the center frequency and Q are independent.