Abstract: A vibration monitoring system employing a capacitive accelerometer determines the energy associated with one or more frequency components within the frequency spectrum of the vibration signal. The capacitive accelerometer operates as a mixer due to its time varying capacitance which provides a measure of the vibration. When the accelerometer is excited by an AC signal the output from the accelerometer comprises beat frequencies due to the mixing of the time varying capacitance and the AC signal. By changing the frequency of the AC signal the location of the beat frequencies in the frequency domain of the accelerometer output can be shifted. Subsequent bandpass filtering to attenuate frequencies except those associated with the frequency component and demodulation to bandshift the energy of the filtered signal energy to DC, creates a DC value which provides a measure of the energy present at the frequency component.

Abstract: An accelerometer arrangement includes an acceleration sensor that includes two capacitor plates having respective parallel mutually facing major surfaces which bound a sensing gap therebetween. A plate-shaped electrically chargeable proof mass is resiliently mounted in the gap in parallelism with the major surfaces for displacement in response to the action of acceleration forces thereon out of a substantially central rest position toward one or the other of the major surfaces depending on the direction of the acceleration forces. An electrical potential difference is established between the capacitor plates to generate respective electrostatic fields between the capacitor plates and the proof mass which cause a proof mass electrical potential variation having a magnitude and sense depending on the extent and direction of the displacement of the proof mass out of its rest position.

Abstract: A sawtooth voltage is applied to an integrated optic phase modulator by means of a high impedance variable current source in response to a charge rate control signal. The phase modulator's capacitance accumulates the charge which manifests a voltage comprising the sawtooth signal. The sawtooth signal is also provided to a comparator which in turn provides a discharge signal upon detecting the sawtooth voltage as being greater than a selected reference signal magnitude. The discharge signal is provided to a means for discharging the accumulated charge from the capacitance of the integrated optic phase modulator. A compensating resistor may be connected between the current source and the phase modulator to automatically correct for sawtooth overshoot.

Abstract: Apparatus and method is disclosed for determining position with light by providing input light at an input light port of an optical cavity having a variable length dimension and detecting light which has traversed the variable length dimension at an output light port of the optical cavity and determining the present length of the variable length dimension using the detected light as a measure.

Abstract: A differential torquer having at least one bifilar winding mounted on the torquer is disclosed. The bifilar winding has opposing polarities and the torquer is particularly well suited for use in reducing the temperature sensitivity of torquer servo loops.

Abstract: A differential torquer servo loop having means for comparing the balance between a torquer position related signal and a signal indicative of the difference in the magnitudes of the currents in the differential torquer and for rebalancing any difference therebetween is disclosed. Total current in the torquer is maintained at a constant level to provide a quiet control loop which promotes temperature stabilization.

Abstract: Serial to parallel conversion circuitry achieves phase synchronization and signal bit sampling of received asynchronous serial data through use of a gate enable delay line oscillator having a selected response time, and selectably enabled in the presence of the received serial data to provide a sampling clock signal for shifting the serial data into register for parallel formatting at a frequency equal to the line frequency.