Abstract: A method for measuring time delay and distance may include providing an electromagnetic radiation carrier frequency and modulating one or more of amplitude, phase, frequency, polarization, and pointing angle of the carrier frequency with a return to zero (RZ) pseudo random noise (PN) code. The RZ PN code may have a constant bit period and a pulse duration that is less than the bit period. A receiver may detect the electromagnetic radiation and calculate the scattering profile versus time (or range) by computing a cross correlation function between the recorded received signal and a three-state RZ PN code kernel in the receiver. The method also may be used for pulse delay time (i.e., PPM) communications.

Abstract: A method for measuring time delay and distance may include providing an electromagnetic radiation carrier frequency and modulating one or more of amplitude, phase, frequency, polarization, and pointing angle of the carrier frequency with a return to zero (RZ) pseudo random noise (PN) code. The RZ PN code may have a constant bit period and a pulse duration that is less than the bit period. A receiver may detect the electromagnetic radiation and calculate the scattering profile versus time (or range) by computing a cross correlation function between the recorded received signal and a three-state RZ PN code kernel in the receiver. The method also may be used for pulse delay time (i.e., PPM) communications.

Abstract: A time interval unit which operates in accordance with electronic sampling techniques and employing a pair of identical sampling interpolators which are respectively triggered at the start and stop of the time interval to be measured. Each time interval unit includes a GHz frequency sinusoidal clock signal generator and a time counter in the form of a pulse counter and a pair of sampling type interpolators which are respectively triggered on in response to a start and a stop signal. When triggered, each interpolator samples the instantaneous amplitude of the in-phase(x) and quadrature(y) components of the sinusoidal clock signal. From the samples of the x and y components and the pulse counter's result, the elapsed time between two events is computed to a psec accuracy.

Abstract: A system determines the surface profile of an object. Systems of this kind are used in industrial robots, such as automatic welders. The severe operating environment requires a vision system with noise immunity along with accuracy. A beam splitter enables the use of discrete optical detectors which eliminate many problems inherent with previously used detectors, such as diode arrays and TV cameras. Additionally, an automatic gain control alters the intensity of a generated optical beam in response to the reflectivity of the surface. These features increase the accuracy and noise immunity of an optical vision system for use in sever industrial applications.

Abstract: Scanning devices are commonly utilized in conjunction with automatically guided welding systems in order to interpret the location and other characteristics associated with a groove to be welded. Many such systems utilize lasers as a source of radiant energy. The instant invention includes a sensing circuit for detecting radiant energy produced by the arc of a welding torch and producing first and second status signals in response to the respective absence and presence of the arc. A logic circuit produces a first power command signal in response to receiving the first status signal and a second power command signal in response to receiving the second status signal. A radiant energy emitting device controllably produces radiant energy having a first relatively low power level in response to receiving the first power command signal and a second relatively high power level in response to receiving the second power command signal.

Abstract: An optical instrument (10), such as a stability monitor or a target range finder, uses an unstabilized laser (12) to project a composite optical signal of coherent light having two naturally occurring longitudinal mode components. A beamsplitter (24) divides the signal into a reference beam (26) which is directed toward one photodetector (28) and a transmitted beam (42) which illuminates and is reflected from a distant target (44) onto a second photodetector (52) optically isolated from the first photodetector. Both photodetectors are operated on the square law principle to provide electrical signals modulated at a frequency equal to the separation between the frequencies of the two longitudinal mode components of the optical signal projected by the laser (12).

Abstract: An optical data communication system is provided whereby two orthogonal polarization states of a light beam carrier correspond to digital states. In such a system, automatic polarization compensation is provided by applying a dither modulating voltage to a cell exhibiting the electro-optic effect. The cell controls the relative phase of electric field components of an input light beam enabling the dither frequency component of the difference of the instantaneous powers in the two polarization states to be coherently detected. A signal derived from the coherent detection process is fed back to the cell via an integrator to form polarization bias compensating servo loop of Type I.