Download or read book The Use of Measurements in Predicting the Performance of Tropospheric Communication Circuits written by Albrecht P. Barsis and published by . This book was released on 1959 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Use of Measurements in Predicting the Performance of Tropospheric Communication Circuits written by A. P. Barsis and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The uncertainty in predicting the performance of tropospheric communication circuits may be expressed by a variance, assuming a log-normal distribution of the differences between calculated and measured values of field strength or basic transmission loss, if a number of paths with identical geometrical and other prediction parameters are considered. It is shown to what extent this variance may be reduced by taking into account transmission loss measurements over the same path for which the prediction is intended, or over a similar path. The improved prediction is obtained by assigning weights to calculated and observed values, respectively, and forming a weighted average. The method is demonstrated by examples, and the results are used to calculate new values of service probability on the basis of the improved prediction. Comparison of service probabilities for predictions based on the cal¿̐ư culation above, and for predictions taking into account the results of transmission loss measurements, enables the designer to judge whether the cost of a measurement program is justified in terms of possible savings in equipment for a final installation.
Download or read book The Use of Measurements in Predicting the Performance of Tropospheric Communication Circuits NBS Report 6043 written by A P Barsis and published by Hassell Street Press. This book was released on 2021-09-09 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. To ensure a quality reading experience, this work has been proofread and republished using a format that seamlessly blends the original graphical elements with text in an easy-to-read typeface. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Download or read book National Bureau of Standards Report written by United States. National Bureau of Standards and published by . This book was released on 1960 with total page 674 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Summary of Research at Boulder Laboratories for the Year written by Boulder Laboratories (U.S.) and published by . This book was released on 1958 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Summary Report of Boulder Laboratories for Year Ending written by Boulder Laboratories (U.S.) and published by . This book was released on 1958 with total page 922 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance Predictions for Single Tropospheric Communication Links and for Several Links in Tandem written by A. P. Barsis and published by . This book was released on 1961 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: Performance of long-distance tropospheric communication circuits, either singly or in tandem, is predicted in terms of the probability of obtaining a specified grade of service or better for various percentages of time. The grade of service is determined by the minimum acceptable ratio of hourly median predetection-RMS-signal-to-RMS-noise for the type of intelligence to be transmitted. The standard deviation of prediction errors depends upon the percentage of hours the specified grade of service is required and on parameters characterizing the propagation path. The possibility of reducing this standard deviation by making path-loss measurements is discussed. It is shown that no improvement is possible unless the test path is very nearly the same as the proposed operational path; in particular, unless the test path and operational paths have terminals less than one mile apart it is shown to be doubtful in most cases whether the observations will be useful in improving the reliability of the predicted performance of the proposed system. Assuming that the test path and proposed operational paths are identical, estimates are given of the number of days of observations required to halve the prediction uncertainty or, alternatively, to reduce it to 3 db; in some cases several years of observations are required. A tutorial discussion is given in Appendix III of the concepts of the effective noise figure and the effective input noise temperature of a receiving system.
Download or read book Predicting the Performance of Long Distance Tropospheric Communication Circuits written by Albrecht P. Barsis and published by . This book was released on 1958 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NBS Technical Note written by and published by . This book was released on 1965-04 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Predicting the Performance of Long Distance Tropospheric Communication Circuits written by A. P. Barsis and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Comparison of calculated and measured values of transmission loss for tropospheric propagation paths shows that there is an appreciable amount of uncertainty in the prediction process. Departures of observed from predicted values may be regarded as normally distributed when expressed in decibels, and this paper considers methods of estimating these standard deviations. In order to predict the performance of a communication system over a given path, it is necessary to define the grade of service, the time availability of this grade of service and the reliability of the predictions. The short-term (within-the-hour) signal fading is conveniently included in the definition of the grade of service, in terms of a required hourly median r.m.s.-carrier to r.m.s.-noise ratio. Next, the time availability of a given grade of service is specified in terms of the percentage of hours in a year that this minimum carrier-to-noise ratio is exceeded. To determine the time availability it is necessary to obtain the distributions with time of hourly medians for the path with given geometrical and meteorological characteristics. In this paper the three concepts, grade of service, time availability, and reliability of prediction are brought together in a single graphical representation. The graph has two probability scales; the ordinate shows the percentage of hours service is available (time availability), and the abscissa shows the service probability (reliability of the prediction), where each curve corresponds to a system with given operating characteristics such as transmitter power, antenna size, etc. Each curve could therefore be labeled by a figure representing installation and operating costs, and various systems may thus be compared on the basis of cost versus probability of successful operation.
Download or read book Prediction of the Cumulative Distribution with Time of Ground Wave and Tropospheric Wave Transmission Loss written by Patricia L. Rice and published by . This book was released on 1959 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measured and Predicted Long term Distributions of Tropospheric Transmission Loss written by A. G. Longley and published by . This book was released on 1971 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications written by United States. National Bureau of Standards and published by . This book was released on 1960 with total page 762 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications United States National Bureau of Standards written by United States. National Bureau of Standards and published by . This book was released on 1960 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications of the National Bureau of Standards written by United States. National Bureau of Standards and published by . This book was released on 1967 with total page 774 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Miscellaneous Publication National Bureau of Standards written by United States. National Bureau of Standards and published by . This book was released on 1934 with total page 1180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Supplementary List of Publications of the National Bureau of Standards written by and published by . This book was released on 1960 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
