Abstract: Systems and methods for calibrating a solid-imaging system (10) are disclosed. A calibration plate (110) having a non-scattering surface (140) with a plurality (150) of light-scattering fiducial marks (156) in a periodic array is disposed in the solid-imaging system. The actinic laser beam (26) is scanned over the fiducial marks, and the scattered light (26S) is detected by a detector (130) residing above the calibration plate. A computer control system (30) is configured to control the steering of the light beam and to process the detector signals (SD) so as to measure actual center positions (xA, yA) of the fiducial marks and perform an interpolation that establishes a calibrated relationship between the angular positions of the mirrors and (x,y) locations at the build plane (23). The calibrated relationship is then used to steer the laser beam in forming a three-dimensional object (50).

Abstract: Systems and methods for calibrating a solid-imaging system (10) are disclosed. A calibration plate (110) having a non-scattering surface (140) with a plurality (150) of light-scattering fiducial marks (156) in a periodic array is disposed in the solid-imaging system. The actinic laser beam (26) is scanned over the fiducial marks, and the scattered light (26S) is detected by a detector (130) residing above the calibration plate. A computer control system (30) is configured to control the steering of the light beam and to process the detector signals (SD) so as to measure actual center positions (xA, yA) of the fiducial marks and perform an interpolation that establishes a calibrated relationship between the angular positions of the mirrors and (x,y) locations at the build plane (23). The calibrated relationship is then used to steer the laser beam in forming a three-dimensional object (50).

Abstract: An optical receiver system for processing signals output from a polarization diversity detector that includes a plurality of photodetector cells. Each cell provides an signal that includes a phase generated carrier signal having a modulation frequency ? and a sensor signal that has an in-phase component I and a quadrature phase component Q superimposed on the phase generated carrier signal. A plurality of variable gain amplifiers are arranged to produce a plurality of amplified signals. A feedback circuit is connected to the plurality of variable gain amplifiers for controlling the gains thereof. A plurality of demodulator circuits are arranged to receive the amplified signals. The demodulator circuits are arranged to provide for each photodetector cell an I signal output that indicates an amplitude of the in-phase component I and a Q signal output that indicates an amplitude of the quadrature phase component Q.

Abstract: A method for selecting a cell from each member of a tri-cell photodetector array used to detect optical signals output from a multichannel sensor array to indicate interference between two optical signals of unknown polarization incident upon the tri-cell photodetector array comprises selecting a cell in each tri-cell photodetector and collecting a selected number of samples of the signal output for each cell. Each sample has an in-phase AC component I and a quadrature AC component Q. An amplitude sum signal E=I*I+Q*Q is calculated for a predetermined number of samples in the selected number of samples of the signal output for each cell. The signal output of cell in each tri-cell photodetector having the largest value of the amplitude sum signal is selected for further processing.

Abstract: A roll stability control system for a pneumatically operated vehicle brake system is implemented using simpler ABS hardware rather than more complex EBS hardware. For each brake chamber or channel, two 3/2 solenoid controlled valves are used. An ECU is operative to control the solenoids. The ECU is preferably operative to provide a selected delivery pressure to the brake chamber without measurement of delivery pressure to the brake chamber. Supply air is provided at a known pressure to a first solenoid controlled valve that is associated with the brake chamber; the amount of time of energization and de-energization of the first valve that is needed to provide an output therefrom of a given pressure, is calculated; and the first valve is energized and de-energized for the calculated times, thereby to cause a low-pressure test pulse to be provided to the brake chamber.

Abstract: In one embodiment, a vehicle braking system, for delivering pressurized air to a brake chamber to achieve a desired braking response, includes an air-pressure controlled relay valve for delivering the pressurized air to the brake chamber. A solenoid receives a variable control input pressure and delivers the control input pressure to the relay valve as a function of a state of the solenoid. An ECU controls the solenoid according to a control model for delivering the pressurized air to the brake chamber and achieving the desired braking response.

Abstract: Apparatus for eliminating sign uncertainty in a coherent phase generated carrier demodulator in a multi-channel sensor system has a downconverter array arranged to separate the in-phase component I and the quadrature phase component of the sensor output for each channel. A coordinate transformer uses the in-phase component and quadrature phase component to calculate an arctangent for the phase angle for each channel. A digital signal processor adds 180° to each arctangent calculation for which the tangent is a negative number.

Abstract: Apparatus for eliminating sign uncertainty in a coherent phase generated carrier demodulator in a multi-channel sensor system has a downconverter array arranged to separate the in-phase component I and the quadrature phase component of the sensor output for each channel. A coordinate transformer uses the in-phase component and quadrature phase component to calculate an arctangent for the phase angle for each channel. A digital signal processor adds 180° to each arctangent calculation for which the tangent is a negative number.

Abstract: A method for selecting a cell from each member of a tri-cell photodetector array used to detect optical signals output from a multichannel sensor array to indicate interference between two optical signals of unknown polarization incident upon the tri-cell photodetector array comprises selecting a cell in each tri-cell photodetector and collecting a selected number of samples of the signal output for each cell. Each sample has an in-phase AC component I and a quadrature AC component Q. An amplitude sum signal E=I*I+Q*Q is calculated for a predetermined number of samples in the selected number of samples of the signal output for each cell. The signal output of cell in each tri-cell photodetector having the largest value of the amplitude sum signal is selected for further processing.

Abstract: An optical receiver system for processing signals output from a polarization diversity detector that includes a plurality of photodetector cells. Each cell provides an signal that includes a phase generated carrier signal having a modulation frequency &ohgr; and a sensor signal that has an in-phase component I and a quadrature phase component Q superimposed on the phase generated carrier signal. A plurality of variable gain amplifiers are arranged to produce a plurality of amplified signals. A feedback circuit is connected to the plurality of variable gain amplifiers for controlling the gains thereof. A plurality of demodulator circuits are arranged to receive the amplified signals. The demodulator circuits are arranged to provide for each photodetector cell an I signal output that indicates an amplitude of the in-phase component I and a Q signal output that indicates an amplitude of the quadrature phase component Q.

Abstract: A backplane module adds a second level of PCI bridges to a single board computer to increase the number of slots controllable by a common host processor. This invention provides a configuration that supports common host control of sixteen PCI slots and an Ethernet interface, a universal system bus (USB) and a SCSI interface resident on the common host single board computer.