Patent ID: 7898150

Claim:
An angular velocity detection apparatus comprising: a surface acoustic wave angular velocity sensor including: a piezoelectric substrate configured to allow a surface acoustic wave to propagate thereon; a plurality of perturbation weights disposed on the piezoelectric substrate; a driving electrode disposed on the piezoelectric substrate and configured to oscillate in accordance with a driving signal to vibrate the perturbation weights with a first vibration; a sensing electrode disposed on the piezoelectric substrate and configured to sense a second vibration of the perturbation weights, the second vibration being caused by a Coriolis force due to an angular velocity; and a first reflector and a second reflector between which the plurality of perturbation weights and the driving electrode are disposed; a driving signal generation unit configured to generate the driving signal; a synchronous detection unit configured to synchronously detect an output signal from the sensing electrode by using a reference signal; a reference signal generation unit configured to generate the reference signal; a first switching unit configured to connect and disconnect a first signal path for inputting the driving signal from the driving signal generation unit to the driving electrode by being switched on and off, respectively; a second switching unit configured to connect and disconnect a second signal path for inputting the reference signal from the reference signal generation unit to the synchronous detection unit by being switched on and off, respectively; and a switching signal generation unit configured to generates: a first switching signal to cyclically switch on and off the first switching unit at predetermined time intervals; and a second switching signal to (i) switch on the second switching unit when a direct arrival wave from the driving electrode is un-inputted to the sensing electrode and (ii) switch off the second switching unit when the direct arrival wave from the driving electrode is inputted to the sensing electrode.