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The question of the suitability of Walsh functions or similar bi-valued functions used as a radar electromagnetic carrier waveform is considered. Walsh functions are described and effective sinusoidal steady state transfer functions are defined for transmission elements, antenna systems, and propagation media. The argument is made that the unit impulse response is suitable in describing the responses of radar elements and the propagation media to such bi-valued excitation waveforms. A measure of the mean, or average, duration of the unit impulse response is defined and used as a measure of the degradation of rise and fall times introduced by radar system elements and the radar environment. It is shown that the mean duration of the impulse response may be easily obtained from the Laplace or Fourier transfer function of an...
This paper presents a study of the resonant transfer of energy between filters with the viewpoint of applying this technique to communication systems. A summary of the existing filter designs for this application is made. This summary shows that a requirement common to all these filters is that the impulse response be zero at the sampling interval. It is further shown that this impulse response requirement in turn dictates that the resonant transfer filter have a 3-dB loss at one-half the sampling frequency. A practical procedure for designing filters meeting this "impulse response zero" criterion is given. The major contribution of this paper is a design method for resonant transfer filters which allows the attenuation at half the sampling frequency to be much greater than 3 dB. The method makes use of the resonant ...
This thesis discusses the field of products liability as it relates to the electronics industry. The historical development of products liability is traced and the various legal theories are examined. These legal theories and background are then used to discuss the judicial obligations imposed upon the manufacturer and seller of equipment with regard to product development and marketing of the product. The usual elements of a typical products liability case are presented and actions which the manufacturer or seller can take to avoid liability both before and after a case is filed are discussed. In the event that a products liability action is successful the damages awarded to the plaintiff are of significant importance to the manufacturer or seller and are therefore discussed. Past decisions and stated objectives of the pr...
This thesis discusses the design of an approximate matched filter capable of detecting a 30 MHz, 0.45 microsecond pulsed carrier in white noise. The theoretical background, which the matched filter is based upon, is presented. The matched filter described herein is composed of an open-end lumped-parameter delay line and a narrow-bandpass amplifier. Passive signal generation is employed by using the fact that the impulse response of a circuit is the inverse Fourier transform of the frequency response of the circuit. In this experiment, therefore, two identical circuits are used; one is for signal generation while the other is for the matched filter. The signal is not reproduced at the output of the matched filter, but the signal-to-noise ratio is maximized. The matched filter circuitry is compact and is economical to build. ...
Digital filtering can be done on a limited scale using an IBM 1620 digital computer. A computer program has been written to aid in the design of digital filters by computing the power spectrum of sampled time data. The power spectrum analysis program was coded in SPS symbolic machine language. Design methods and use are demonstrated for two simple types of digital filters. Digital filtering with noisy data is considered. The use and limitations of an IBM 1620 digital computer as a digital filtering system are discussed.
This paper presents a theoretical study of real-time bandwidth compression systems using the Hilbert transform and associated analytic signal concept. An analytic signal is defined as u(t) = s(t) + [superscript ¯]js(t) , where [superscript ¯]s(t) is the Hilbert transform of the signal s(t). A complete discussion of the properties of analytic signals is included. Speech bandwidth compression is emphasized, but the proposed compression schemes can be applied to any narrow-band (band-limited signal. The extent of compression depends largely upon the characteristics of the input signal. Two presently used real-time speech bandwidth compression systems, the Vobanc and channel Vocoder, are described in order to provide a comparison between the proposed systems and existing systems designed without recourse to analytic signal idea...
A brief history of X-ray control methods is presented, and the instrumentation requirements and physiological considerations pertaining to an automatic X-ray control system are discussed. The latter half of the thesis describes the design and operation of a device which will permit medical radiographs to be taken automatically and at any specified point in the cardiac or respiration cycle.
A survey of federal and state agencies was conducted to determine the future need for water-quality data. This survey was used as the basis for constructing a water-quality data aquisition system applicable to any river basin. This study outlines the major components of an automatic water-quality monitoring system. Seventy-one sites in the Willamette River basin of Oregon were selected as monitoring sites for a model monitoring system. VHF radio and telephone telemetry systems were designed to service the model monitoring system. Economic models of the telemetry systems were constructed and compared. The results of this study show that: 1. Enough interest in water-quality monitoring exists to justify the construction of an automated monitoring system. 2. The model monitoring system developed in this study may be adapted t...
This thesis discusses the analysis, design, and experimental evaluation of an instrument that can be used to detect the presence or absence of a signal, not necessarily known, in a noisy background. The detection principle is based on application of the sign test of distribution-free statistics to the stochastic process defined by the zero-crossing intervals of a signal or signal plus noise process. It is shown that the detector is distribution free in the sense that the false-alarm probability can be evaluated with only a limited knowledge of the statistics of the underlying noise process. A theoretical discussion of the detection principle and false alarm probability analysis is presented in conjunction with design considerations of the circuitry used to implement the zero-crossing analyzer technique. Results of an experi...
The problem that is attacked in this paper is that of analyzing and predicting the response of a balanced detector when it is driven by short, periodic bursts of RF energy. There is, however, sufficient information provided to extend the analysis to virtually any circumstance of balanced detector operation. The problem is solved by developing an equivalent circuit for the balanced detector. The equivalent circuit provides a basis for developing an intuitive understanding of the detector operation. A mathematical analysis of the equivalent circuit provides a second method of determining the detector response and serves, also, to substantiate the intuitive methods. Some guidelines are established from the results of the analysis that can be used in designing a system. These guidelines provide a means of obtaining a desired sy...
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