DELAY FEEDBACK TYPE SURFACE ACOUSTIC WAVE VOLTAGE CONTROLLED OSCILLATOR

摘要

PURPOSE:To provide the delay feedback type surface acoustic wave voltage controlled oscillator having satisfactory characteristics without any externally attached equipment by simultaneously obtaining two signals of different phases. CONSTITUTION:A surface acoustic wave element 101 is equipped with outside electrodes 203 and 204 to output each one output signal. These output side electrodes are arranged on both the side of the surface acoustic wave propagating direction of an input side electrode 202 which impedance is matched with that of an outside circuit, the output side electrode is composed of the plural pairs of electrode fingers, each electrode finger pair is separately arranged in the integer-fold surface acoustic wave propagating direction of a surface acoustic wavelength, the electrode finger pairs of the inputside electrode and the outputside electrode are mutually arranged while being shifted only for distance difference to get phase difference required for a phase shifter when one surface acoustic wavelength is defined as 2pi, the output signal of the surface acoustic wave element is inputted to the phase shifter, the output is inputted to a feedback amplifier, and the output is fed back to the surface acoustic wave element.