Apparatus to remotely move a mirror in a laser The driving means operates against a thin membrane forming a portion of the laser housing so that a mirror fastened to the inside of the membrane may be moved as desired

Gas ring laser gyroscope system

Adjustable, thin membrane mirror for use in the stabilization of ring lasers

A very high resolution laser gyroscope system having a phased-locked loop operatively coupled to one or more frequency difference outputs from a laser gyroscope cavity. Waves of at least four frequencies propagate around the gyroscope cavity, with output signals being formed having a frequency equal to the difference between the frequencies of wave pairs. In one set of embodiments of the invention, the frequency difference signal for one wave pair is phase-locked to an external reference source. A signal applied to a Faraday rotator bias coil provides the frequency shifting of the wave pairs necessary to achieve phase lock. The amplitude of the signal applied to the Faraday bias coil provides a highly precise measure of the rate of rotation. In another set of embodiments of the invention, one or more of the wave pair frequency difference signals are coupled as inputs to an external phase-locked loop in which a voltage controlled oscillator is followed by a frequency divider of the feedback circuit. In these embodiments, the output of the voltage controlled oscillator provides an output signal which has a frequency in proportion to but many times higher than the frequencies of the wave pair difference signals. In still further embodiments of the invention, the two phase-locked loop techniques may be combined. In all of the disclosed systems, the quantization error normally associated with laser gyroscope output signals is substantially reduced.

Phase-locked loop laser gyroscope system

In an internal combustion engine, a latch member is movable to and from a latching position in which it prevents a valve from coming nearer its seat than a predetermined distance therefrom. A cam follower connected with the latch member cooperates with axially adjacent first and second cam elements. The first causes the latch member to be held out of latching position during most of the engine cycle at all speeds, but at cranking speeds causes it to move to latching position just before the valve, in closing, reaches said distance from its seat. Once in latching position, the latch member is trapped there until opening movement of the valve carries it beyond said distance from its seat. The second cam element, carried by a flyweight, so cooperates with the first at running speeds as to hold the latch member out of latching position throughout the cycle.

Automatic compression relief mechanism for internal combustion engines

A ring laser gyro has a pair of counter-rotating beams, the difference frequency between the beams being indicative of the rotational rate to which the instrument is subjected. The beams are frequency modulated to minimize frequency-locking therebetween. A servo control is provided to maintain the modulation index of the frequency modulation to an optimum value for minimal frequency-locking between the beams.

Gas ring laser gyroscope system

Citations

Adjustable, thin membrane mirror for use in the stabilization of ring lasers

Phase-locked loop laser gyroscope system

Automatic compression relief mechanism for internal combustion engines

Modulation servo control for frequency modulated ring laser gyro

Gas ring laser using oscillating radiation scattering sources within the laser cavity

References

Frequency stabilized laser

Relativistic inertial reference device

Optical interferometric navigational instrument

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