PHASE SHIFTER AND RADIO COMMUNICATION EQUIPMENT

摘要

PROBLEM TO BE SOLVED: To provide a phase shifter where amplitude of signals at different phases is equal to each other with excellent phase precision. SOLUTION: A ring oscillator is formed by connecting an odd number of inverters (INV1, INV2, INV3) whose delay times are adjustable depending on a voltage received from a control terminal in a ring and a load capacitor (C10, C11, C12) is connected to each output terminal of each inverter respectively to lead out signals with a phase deviation of 90 deg. from the inverter terminals. The frequency dependence of the amplitude of the output signal is reduced and the output signal as above is obtained to eliminate the need for any amplifier at the post-stage of the phase shifter and to improve the phase precision.