Abstract:
A chemical analysis system for analyzing a plurality of independent specimens that have time varying characteristics includes a circumferential array of analysis regions that hold the specimens. The analytical regions are sequentially and repetitively sensed and resulting analysis signals corresponding to monitored specimen characteristics are stored in corresponding memory locations. A signal transmission channel connected between the sensor and the memory includes a signal storage capacitor and variable slew rate circuitry. The stored data signal value from the location in memory corresponding to the next analysis region to be sensed is applied to the signal transmission channel while the slew rate circuitry is set in a fast slew rate condition to preset the storage capacitor, and then the data signal generated by said sensor is applied to the signal transmission channel while the slew rate circuitry is set in a slow slew rate condition to adjust the data signal value in the storage capacitor to the current analysis signal value provided by the sensor.
Abstract:
A reflection densitometer includes a light source and a photodetector having an output which has a signal component characteristic of the amount of reflected light received from a surface to be measured and a noise component. The noise component of the output is isolated in time by switching the light source on and off so as to create alternating first and second time periods during which the output of the photodetector is characteristic of only the noise component and in which the output of the photodetector is characteristic of both the signal component plus the noise component, respectively. The output of the photodetector during the second time period is subtracted from the output during the first time period to obtain a signal characteristic of only the output of the photodetector characteristic of relected light received. The signal is held constant during the first and second periods by a sample and hold circuit adapted to sample the signal during the second periods and to hold the sampled signal during the first periods.
Abstract:
Apparatus for controllably admitting a sample volume of engine exhaust into a bifurcated, closed-loop opacity chamber and wherein the exhaust sample is controllably directed away from the internal optics via symmetric flow inducing air guides. A pulsed light source is controllably directed through the opacity chamber and exhaust sample and the detected light is compared to a reference level so as to determine a relative measure of the sample's opacity. Attendant control circuitry permits the selected display of corresponding sample opacity and density values.
Abstract:
A chemical analysis system for analyzing a plurality of independent specimens that have time varying characteristics includes a circumferential array of analysis regions that hold the specimens. The analytical regions are sequentially and repetitively sensed and resulting analysis signals corresponding to monitored specimen characteristics are stored in corresponding memory locations. A signal transmission channel connected between the sensor and the memory includes a signal storage capacitor and variable slew rate circuitry. The stored data signal value from the location in memory corresponding to the next analysis region to be sensed is applied to the signal transmission channel while the slew rate circuitry is set in a fast slew rate condition to preset the storage capacitor, and then the data signal generated by said sensor is applied to the signal transmission channel while the slew rate circuitry is set in a slow slew rate condition to adjust the data signal value in the storage capacitor to the current analysis signal value provided by the sensor.
Abstract:
A solar blind corona camera designed specifically for use on 60 Hz or 50 Hz AC power distribution equipment is based on the fact that electrical discharge corona only occurs above some voltage threshold level on the positive and negative voltage peaks of the AC power waveform. Between these peaks, when the AC voltage is below the discharge corona voltage threshold, the electrical discharge and resulting corona are extinguished. An image sensor is used to both capture the corona-plus-ambient light image during the corona period and the ambient light image during the non-corona period. The ambient light image is then subtracted from the corona-plus-ambient light image leaving only the corona light image which is annunciated and displayed along with the ambient light image. This process effectively renders the corona camera solar blind so it can be used both at night and during daylight.
Abstract:
System and method for analyzing pulses from an excimer laser by measuring light energy rather than heat energy. The output of the laser is monitored with a photodetector to provide electrical current pulses corresponding to the intensity of the light in individual ones of the laser pulses. The current pulses are integrated to provide voltages corresponding to the light energy of the laser pulses, and the voltages are converted to digital signals. The digital signals are accumulated during the exposure period to determine the total light energy of the pulses during that period and also during a shorter interval of time during the exposure period. The light energy for the interval is divided by the length of the interval to determine the average intensity of the pulses during the interval. Displays are provided for the light energy and the intensity of the pulses, as well as the length of the exposure period.