Abstract: A method and apparatus for detecting and controlling the conditions needed for starting and maintaining mode-locked operation of a laser system including a fiber oscillator and high power fiber amplifier. The invention is used to monitor the output power and repetition rate of the fiber oscillator and control the operation of the oscillator such that the oscillator obtains and maintains correct mode-locked operation despite changes in environmental conditions such as temperature, and also with changes due to component aging or degradation.

Abstract: The present invention is directed to a method and apparatus for detecting reflected pulses from multiple targets in a field of view such that range to each target can be detected with high resolution, even when the targets are located over a relatively wide measurement range. Exemplary embodiments of the present invention can provide real-time acquisition of ranging data, and can be implemented in a practical cost-effective manner suitable for reconfiguration.

Abstract: The present invention relates to an apparatus and a method for detecting pulses of light energy from at least two fields of view. A first detector having a first bias detects a pulse received at a first point in time. A second detector having a second bias, different from the first bias, detects a pulse received at a second point in time. A processor compares an output of the first detector with a first threshold to produce a signal representing receipt of a pulse from a first field of view. The processor also compares an output of the second detector with a second threshold, different from the first threshold, to produce a signal representing receipt of a pulse from a second field of view. Because the detectors are biased with different biases, the detected pulses are easily distinguished. Thus, multiple fields of view can be detected without complex hardware. The detectors can be biased with opposite polarities so that background noise is cancelled out.

Abstract: The decoder herein described recovers the clocking and the data in a binary format from a three level coded signal. The decoder has application to data rates in excess of one half gigabits per second, which are common to optical communication channels. The decoder employs a comparator for evaluating to two bit accuracy each state of the signal, a two stage, two bit per stage shift register, and decision logic for recovering the data in a binary format. The decoder is monolithically integrated using buffered FET logic on a gallium arsenide substrate. In the decoder, the comparator is optimized by the use of three zero crossing detectors, one of which has a zero input for reference purposes, in combination with two internal voltage dividers and two external voltage references for achieving an accurate drift free determination of the levels of the three level code (TLC) signal.

Abstract: A circuit, for providing a periodic signal of programmably controllable amplitude, includes an oscillator having a substantially constant amplitude signal of desired frequency and waveform at an output thereof connected to the input of a first programmable voltage divider having its output connected to one input of an operational amplifier. The remaining operational amplifier input is connected to the output thereof via a second programmable voltage divider used as a programmably controllable feedback network. The operational amplifier output signal amplitude may be controlled by external data signals to values less than, equal to, and greater than, the substantially constant oscillator waveform amplitude. Both computer and hard-wired circuitry for controlling the output signal are disclosed. An isolation-and-rectification network may be used to recover a D.C. voltage of programmably controlled amplitude.

Abstract: A control module for controlling at least one variable-power-consuming load responsive to data input from local and/or remote locations, utilizes a controller microcomputer having an output setting the gain of a variable gain amplifier. The variable gain amplifier operates on a substantially-constant output of an oscillator to provide, on a cycle-by-cycle or long-term basis, a periodic waveform of controlled amplitude to the at least one load. The amplitude of the waveform sets the energy consumption/output of the load. Another data bus facilitates connection of local control means to a control module interface providing local control information to the controller microcomputer, while a third data bus is dedicated to communication with a remote central controller, if used.

Abstract: A circuit, for providing a periodic signal of programmably controllable amplitude, includes an oscillator having a substantially constant amplitude signal of desired frequency and waveform at an output thereof connected to the input of a first programmable voltage divider having its output connected to one input of an operational amplifier. The remaining operational amplifier input is connected to the output thereof via a second programmable voltage divider used as a programmably controllable feedback network. The operational amplifier output signal amplitude may be controlled by external data signals to values less than, equal to, and greater than, the substantially constant oscillator waveform amplitude. Both computer and hard-wired circuitry for controlling the output signal are disclosed. An isolation-and-rectification network may be used to recover a D.C. voltage of programmably controlled amplitude.

Abstract: Circuits for providing a variable-amplitude D.C. analog control signal to a load, responsive to the time duration of a periodic, variable-pulse-width input signal, while providing isolation between the input signal circuit and the load circuit. Embodiments utilizing either a fly-back transformer or an optoelectronics isolator, are disclosed.

Abstract: A circuit, for controlling the output level of a load circuit connected thereto, has a single input for receiving a control signal to provide both a selectable level on/off output signal at a first output connected to an on/off terminal of the load circuit, and a pair of essentially equal control currents drawn in shunt from a pair of output terminals connected to load output-level-setting input terminals. The shunt control currents are provided by a current-mirror circuit having a pair of substantially identical current sinks, each responsive to an input signal applied thereto in parallel from the single control circuit input.