Oscillation circuit having a positive feedback oscillation loop and a signal selection part

摘要

An oscillation circuit is provided including a differential amplifier having plural output terminals that provide output signals having different phases from each other, a SAW resonator, and a phase shift circuit, wherein the differential amplifier, SAW resonator, and phase shift circuit forming a positive feedback oscillation loop and a switch circuit being provided for selecting one of the output terminals of the differential amplifier to complete the positive feedback oscillation loop. The switch circuit selects one of the signals SQ1 and SQ2 and transmits it to the phase shift circuit. The phase shift circuit transmits output signals that result from a predetermined phase shift of input signals to the SAW resonator.