Abstract: An amplifier circuit with a high pass filter is constructed to include an operational amplifier (op amp) with a feedback loop in which a capacitor is in parallel with a field effect transistor (FET) configured as a gate tunneling resistor. To configure as a gate tunneling resistor, the source and drain of the FET are tied together, and large resistance is provided through the thin oxide layer between the gate and the source/drain. A bias voltage to the FET can be provided through a separate FET, also configured as a gate tunneling resistor. Additional gate tunneling FETs, also in parallel with the capacitor, can be switched into the circuit in order to provide different resistances, and thus different corner frequencies of the filter. Bias voltages may be supplied by one or more gate tunneling FETs. A fully differential op amp can have complementary feedback loops from its differential outputs, each feedback loop employing one or more gate tunneling FETs.

Abstract: A precision gyroscope which provides mode matching which is insensitive to rate input in response to continuously monitoring the split between the resonances of the drive and sense modes. A calibration signal, having at least one modulated term whose carrier is synchronous with the excitation in the drive resonator is utilized to modify the feedback signal in the sense resonator. The gyroscope thus does not suffer from corruption of, or from, the rate measurement; whereas the frequency of the calibration signal can be chosen independently of the bandwidth of the rate input.

Abstract: A precision gyroscope which provides mode matching which is insensitive to rate input in response to continuously monitoring the split between the resonances of the drive and sense modes. A calibration signal, having at least one modulated term whose carrier is synchronous with the excitation in the drive resonator is utilized to modify the feedback signal in the sense resonator. The gyroscope thus does not suffer from corruption of, or from, the rate measurement; whereas the frequency of the calibration signal can be chosen independently of the bandwidth of the rate input.

Abstract: A vibratory gyroscope system having a mechanical resonator (proof mass) and drive circuitry for maintaining oscillation in two axes at a small frequency split. Angular rate input is shifted to the frequency split and modulates both the frequency (FM) and the amplitude (AM) of the oscillations. Unlike other gyroscope modulation techniques which derive rate information from only the FM information and are subject to aliasing for rate signals with bandwidth exceeding the modulation frequency, the innovation uses both the FM and AM information. By exploiting their orthogonality, the image frequencies from the modulation cancel, thus removing the bandwidth limitation.

Abstract: A vibratory gyroscope system having a mechanical resonator (proof mass) and drive circuitry for maintaining oscillation in two axes at a small frequency split. Angular rate input is shifted to the frequency split and modulates both the frequency (FM) and the amplitude (AM) of the oscillations. Unlike other gyroscope modulation techniques which derive rate information from only the FM information and are subject to aliasing for rate signals with bandwidth exceeding the modulation frequency, the innovation uses both the FM and AM information. By exploiting their orthogonality, the image frequencies from the modulation cancel, thus removing the bandwidth limitation.

Abstract: A vibratory gyroscope system is described which utilizes a mechanical resonator having a first mode of vibration and an associated first natural frequency, and a second mode of vibration having an associated second natural frequency. The angular rate of motion input couples energy between the first and second modes of vibration. The gyroscope has driver circuits, sensors and actuators for the first and second modes. The invention utilizes a bias error shifting method which provides for shifting the bias error away from DC to a higher frequency, where it can be removed by low pass filtering. As a result of the inventive method, gyroscope systems can be produced with significantly lower bias error.

Abstract: A vibratory gyroscope system is described which utilizes a mechanical resonator having a first mode of vibration and an associated first natural frequency, and a second mode of vibration having an associated second natural frequency. The angular rate of motion input couples energy between the first and second modes of vibration. The gyroscope has driver circuits, sensors and actuators for the first and second modes. The invention utilizes a bias error shifting method which provides for shifting the bias error away from DC to a higher frequency, where it can be removed by low pass filtering. As a result of the inventive method, gyroscope systems can be produced with significantly lower bias error.