66,824 research outputs found

    Data reduction, management, and analysis software for CID

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    In an overview of the Data Reduction System, three major steps are examined. First, the raw data tapes were selected from the onboard recorders. These tapes should provide the best quality data for the data reduction software system. These tapes contained 352 channels of data, plus the monitor channels recorded in 8 bit Pulsed Coded Modulation (PCM) words. The next step consists of transcribing the PCM tapes from 8 bit serial digital data to 8 bit parallel digital data. This puts the data in the correct format for processing. The transcription process was accomplished here at LaRC in the Central Data Transportation Facility (CDTF). The last step in this 3 step process is to process the data through the reduction system developed for the Impact Dynamic Research Facility in the early part of 1980. Processing system criteria, system interface routines, and engineering units program that reads digitized data from tapes, and file management programs are discussed

    Enhanced backscatter of optical beams reflected in turbulent air

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    Optical beams propagating through air acquire phase distortions from turbulent fluctuations in the refractive index. While these distortions are usually deleterious to propagation, beams reflected in a turbulent medium can undergo a local recovery of spatial coherence and intensity enhancement referred to as enhanced backscatter (EBS). Using a combination of lab-scale experiments and simulations, we investigate the EBS of optical beams reflected from corner cubes and rough surfaces, and identify the regimes in which EBS is most distinctly observed.Comment: 10 pages, 8 figure

    Fatigue failure load indicator

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    An indicator for recording the load at which a fatigue specimen breaks during the last cycle of a fatigue test is described. A load cell is attached to the specimen which is alternately subjected to tension and compression loads. The output of the load cell which is proportional to the load on the specimen is applied to the input of a peak detector. Each time the specimen is subjected to a compression load, means are provided for applying a positive voltage to the rest of the peak detector to reset it. During the last cycle of the tension load the peak detector measures the maximum load on the specimen. Means are provided for disconnecting the load cell from the peak detector when there is a failure in the specimen

    IECM calibration and data reduction requirements

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    The induced environment contamination monitor (IECM) tape recorder format, as it relates to the ouput of meaningful data from the IECM instrument, is explained. Eight-bit words (or bytes) generate numbers that represent voltage levels of electronic detection probes for each experiment. This information is amalgamated by the IECM Data Acquisition and Control System (DACS). In some cases bits represent certain status situations concerning an experiment, such as whether a valve is opened or closed. Voltages are transformed into meaningful physical phenomena through equations of calibration. Data formats and plots are generated as requested for each IECM experimenter

    High power phase locked laser oscillators

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    The feasibility of mechanizing an adaptive array of independent laser oscillators for generation of a high power coherent output was experimentally investigated. Tests were structured to evaluate component/system requirements for delivery of energy to a low-earth orbit satellite. Initial experiments addressed the control issues of phase locking unstable resonators at low power levels. A successful phase lock demonstration formed the basis for the design and fabrication of the high power, water-cooled, control mirror subsequently installed in the NASA LeRC high power laser. Tests were performed to characterize the operational limits of the laser system and included quantitative assessment of the frequency stability, noise sources, and optical properties of the beam

    The development of a pseudo-nyquist analysis technique for hybrid sampled-data control systems

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    The stability characteristics of a launch vehicle, as a function of gain and phase variations at the thrust vector controller, cannot be obtained using classical sampled-data control theory if the launch vehicle attitude control system contains both sampled-data and continuous feedback control loops. A method was developed which can be used to generate a sampled-data pseudo-Nyquist plot for gain and phase variations at the controller. This method was developed and used to determine the stability characteristics of the Saturn 1B launch vehicle in the backup guidance mode

    Recent Developments in the Use of Loran

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    Loran Recieving Equipment for the Mariner

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