Abstract: The shape of drive electrodes and/or the shape of detection electrodes of a tuning fork type vibration gyro are made asymmetrical between the inside and outside of the arm, and between the surface and reverse face of the arm, to reduce the abnormal vibration and leaking output. The drive electrodes to be provided on the inside parts of the surface and reverse face of the first arm are formed smaller than the drive electrodes to be provided on the outside parts of the surface and reverse face thereof. The length of the detection electrode to be provided on the outside lateral face of the second arm is formed short. The drive electrodes to be provided on the surface and reverse face of the first arm are extended to the base side from the boundary position between the first arm and the base, and the detection electrodes to be provided on the surface and reverse face of the second arm are extended to the base side from the boundary position between the second arm and the base.
Type:
Grant
Filed:
October 7, 1999
Date of Patent:
December 11, 2001
Assignees:
Fujitsu Limited, Fujitsu Towa Electron Limited
Abstract: A detection circuit for a vibratory gyro includes a first circuit which detects a detection signal output from the vibratory gyro and produces an output signal indicative of an angular velocity applied to the vibratory gyro, and a second circuit which is operatively coupled to the first circuit and reduces a leakage component included in the detection signal.
Type:
Grant
Filed:
March 11, 1997
Date of Patent:
May 15, 2001
Assignees:
Fujitsu Limited, Fujitsu Towa Electron Limited
Abstract: In a tuning fork type vibration element provided in a tuning fork type vibration gyro, the sum of inertial moments of a base to an inertial moment of two arms is 1.0 or larger. The inertial moment of the two arms is obtained by multiplying the square of a rotation radius, which is a distance from a center axis of torsional vibration as a center position between the two arms to a center of gravity of the two arms with a mass of the two arms, and the inertial moment of the base is obtained by multiplying the square of the rotation radius from the center axis of the same torsional vibration.
Type:
Grant
Filed:
April 28, 1998
Date of Patent:
August 22, 2000
Assignees:
Fujitsu Limited, Fujitsu Towa Electron Limited
Abstract: The shape of drive electrodes and/or the shape of detection electrodes of a tuning fork type vibration gyro are made asymmetrical between the inside and outside of the arm, and between the surface and reverse face of the arm, to reduce the abnormal vibration and leaking output. The drive electrodes to be provided on the inside parts of the surface and reverse face of the first arm are formed smaller than the drive electrodes to be provided on the outside parts of the surface and reverse face thereof. The length of the detection electrode to be provided on the outside lateral face of the second arm is formed short. The drive electrodes to be provided on the surface and reverse face of the first arm are extended to the base side from the boundary position between the first arm and the base, and the detection electrodes to be provided on the surface and reverse face of the second arm are extended to the base side from the boundary position between the second arm and the base.
Type:
Grant
Filed:
January 27, 1998
Date of Patent:
December 7, 1999
Assignees:
Fujitsu Limited, Fujitsu Towa Electron Limited
Abstract: An oscillation circuit of phase-shift type includes a surface acoustic wave filter in a feedback circuit, the surface acoustic wave filter having first and second one-port surface acoustic wave resonators of different resonance frequencies connected in a ladder configuration. The oscillation circuit has a high C/N ratio with a large bandwidth of variable frequency and can be fabricated in a small size with low costs.
Type:
Grant
Filed:
September 25, 1997
Date of Patent:
February 23, 1999
Assignees:
Fujitsu Limited, Fujitsu Towa Electron Limited