Abstract: An apparatus for eliminating or reducing vibration-induced errors due to vibration rectification by applying a variable weighting function at the demodulator or analog-to-digital converter by changing the size of the demodulator reference signal or the converter gain, respectively. The changing is performed within the frequency spectrum of the vibration. Sampling of the detector output may be utilized and the samples are accumulated and processed to remove the variations due to vibration, and the rotation rate is recovered by digital demodulation.

Abstract: A rectification error reducer for a fiber optic gyroscope, which is an intensity servo or compensator for reducing vibration effects in the optical signals caused by modulation at vibration frequencies induced by the gyroscope operating environment. The vibration effects may be detected in signals from the photodiode output in amplitude form which is used in a control system to null out optical intensity variations at the frequencies of vibration.

Abstract: A rectification error reducer for a fiber optic gyroscope, which is an intensity servo or compensator for reducing vibration effects in the optical signals caused by modulation at vibration frequencies induced by the gyroscope operating environment. The vibration effects may be detected in signals from the photodiode output in amplitude form which is used in a control system to null out optical intensity variations at the frequencies of vibration.

Abstract: A light source with wavelength compensation for a fiber optic rotation sensor includes a light source to provide light for input to the fiber optic rotation sensor. A source control circuit generates a source control signal representative of the temperature of the light source. A driver generates a drive signal as a function of the source control signal to drive the light source. One of a plurality of scale factors for the fiber optic rotation sensor is generated also as a function of the source control signal over a predetermined temperature range. The source control circuit includes a temperature sensor which provides a current signal representative of the temperature of the light source and a buffer network for sinking the current signal and for generating a source control voltage as the source control signal.

Abstract: A bias modulation amplitude monitoring system for a rotation sensor having a pair of output signal component detectors to provide magnitudes of the corresponding frequency components in that signal which are used by a component relationship determination arrangement capable of adjusting the output signal to have a selected value in a range of values for a selected rate of rotation thereof, and to correct variations therein.

Abstract: An integrating analog-to-digital converter system in which alternating and different combinations of signals are integrated, and which are selected for such integration both periodically and through an integrating result reaching a reference value in the periods. A digit count is provided as a system output indicating the time duration of integration of a selected signal combination in each period.

Abstract: A phase difference controller for a rotation sensor based on a coiled optical fiber operating a dual output generator in a feedback loop to provide a pair of signals to operate a pair of frequency translating devices in the optical path with the coil. A pair of sawtooth-like signals of appropriate frequency and polarity operate the frequency translating device to provide a phase difference shift in the optical path.

Abstract: A quartz crystal vibrating diaphragm pressure sensor includes a primary quartz crystal body having a diaphragm formed therein and electrodes on each side of the diaphragm for piezoelectrically exciting thickness shear mode oscillations of said diaphragm, said oscillations varying in frequency in accordance with variations in fluid pressures applied to the surfaces of said diaphragm. A second identical or substantially identical diaphragm similarly excited but exposed to a constant pressure provides a reference frequency for providing precision difference frequency pressure measurement and for inherently compensating for ambient conditions affecting both diaphragms.

Abstract: In a gyroscopic reference system of the type having force rebalanced or flexure suspended gyroscope rate sensors and pulse width modulated torquer signals, undesirable transformer like coupling between the torquer coils and the pick-off coils and transformer like coupling between the torquer coils themselves causes a bias drift error. The transformer coupling and the bias drift error are alleviated or substantially eliminated by selecting the pick-off excitation frequency to be a non-integer multiple of the torquer coil frequency and by delaying the trailing edges of the pulses of the pulse width modulated torquer signals.