{"title":"Evaluation of νth-law devices","authors":"K. Fu, T. Chin","doi":"10.1109/TCOM.1961.1097674","DOIUrl":"https://doi.org/10.1109/TCOM.1961.1097674","url":null,"abstract":"Most of the work which has been done in the analysis of a νth-law device is concerned with the statistical properties of the output. Apparently, a general investigation to determine the optimum value of ν for a νth-law device has never been made. Therefore, a simple method of evaluating a νth-law device is necessary. This may be done by choosing the optimum value of ν based on the criterion for masimizing the detector output information capacity. It is shown that when the input of a νth-law detector consists of an amplitude modulated (AM) sine-wave signal and a stationary narrow-band white Gaussian noise, the square-law detector will give maximum output information capacity for very small input signal-to-noise ratio (SNR). In the case of a very large input SNR and a normally distributed signal modulating process on the AM sine wave signal, the linear detector will be considered as an optimum one.","PeriodicalId":154431,"journal":{"name":"IRE Transactions on Communications Systems","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1961-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127861579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Theoretical limitations on frequency and time diversity for fading binary transmissions","authors":"J. Pierce","doi":"10.1109/TCOM.1961.1097668","DOIUrl":"https://doi.org/10.1109/TCOM.1961.1097668","url":null,"abstract":"The purpose of this note is to point out that for either frequency diversity or time diversity, the dependence of required transmitted power on number of branches is quite different than for space diversity. For both frequency- and time-diversity techniques the saving of transmitter power can come only from the first factor above (that is, the averaging of fluctuations), since the total mean received power is a fixed fraction of the scattered power. It will be shown that as a consequence: 1) The minimum required transmitter power for a specified reliability is strictly larger than zero. 2) Both the value of this minimum and the number of diversity branches yielding the minimum depend upon the diversity-combining method used.","PeriodicalId":154431,"journal":{"name":"IRE Transactions on Communications Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1961-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130469824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Recording type direction finder","authors":"K. Miya, S. Matsushita","doi":"10.1109/TCOM.1960.1097616","DOIUrl":"https://doi.org/10.1109/TCOM.1960.1097616","url":null,"abstract":"The authors formerly made a report on a direct vision type direction finder for high frequency, which has high sensitivity and by which multiple signals or scattering signals can also be measured. Since then, the finder has been used for studying characteristics of the ionospheric propagation waves. In order to make continuous measurement of bearing convenient, a recording apparatus adaptable to the present direction finder has recently been developed. The diagram of the whole system of the direction finder is shown. The left part of the figure shows a diagram of the former finder and the right part surrounded by dash lines is the recording part. The finder adopts the so-called one-receiver system in which a receiver REC amplifies four kinds of voltages of different directivities in succession as time-division signals by using electric switching. Aside from the general explanation of the finder, the working principle of the recording part is briefly described.","PeriodicalId":154431,"journal":{"name":"IRE Transactions on Communications Systems","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1960-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129750925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"White Alice System - Design and Performance","authors":"A. Durkee, D. Metcalfe, W. Tidd","doi":"10.1109/TCOM.1959.1097592","DOIUrl":"https://doi.org/10.1109/TCOM.1959.1097592","url":null,"abstract":"White Alice is an extensive communications network covering the entire state of Alaska. It provides essential defense communications as well as service for other government agencies and civilian commercial service. Both telephone and telegraph channels are provided with capacity for future growth. The Western Electric Company, as prime contractor for the USAF AMC, undertook the engineering, procurement, and installation of the electronic equipment as well as construction of some of the sites. The Bell Telephone Laboratories participated in the basic systems engineering and furnished consulting assistance in new scientific areas. New designs were made or supervised by the Laboratories. The White Alice system plan is based on the study by the Bell System of the communications needs of the area. Radio transmission was chosen for the majority of the routes. Wire and cable were considered either unreliable or impractical in the Alaskan terrain and climate. Where several hundred voice channels were required, microwave line-of-sight radio was used. For the majority of the links, tropospheric beyond-horizon transmission was used because of the economy and simplification of maintenance and logistic problems. The transmission objectives for the entire system were a median noise in the worst month of 38 dba and a maximum of 1 per cent outage in the worst month. These objectives were for 4000-mile circuits and were prorated to each link. The microwave portions of the system were engineered in the same way that has been used previously. Tropospheric beyondhorizon was a relatively new mode of radio transmission and the engineering procedures were less well defined. Propagation experience from a year-long test in Newfoundland, in addition to research by other groups, were used as the basis for the system engineering. These data include variation of signal strength from day to day and seasonally, the effective gain of the large antennas employed, the characteristics of the rapid fading typical of tropospheric propagation, and the effects of geographical profile and separation of the stations. Towards the completion of the project, comprehensive transmission tests were made of many of the links of the system to determine that the design objectives had been met. In particular, a 2400-mile circuit traversing much of the system was tested. The transmission stability and noise performance over a 30-day period was well within the limits set in the objectives. Teletype and voice performance were eminently satisfactory. White Alice has been operating continuously since it was turned over to the Air Force in March, 1958. Its reliability has been gratifying to the military and other agencies using it. It is certain to be a significant factor in the development of this last frontier.","PeriodicalId":154431,"journal":{"name":"IRE Transactions on Communications Systems","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1959-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129721425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Tropospheric Scatter Path Loss Tests - Florida Bahamas","authors":"K. Stiles","doi":"10.1109/TCOM.1959.1097567","DOIUrl":"https://doi.org/10.1109/TCOM.1959.1097567","url":null,"abstract":"Telephone service between the United States and the Bahama Islands is now provided by means of high-frequency radio systems working in the 2-7 mc range. To handle properly the large volume of traffic during the peak winter season requires that more than the present nine circuits be provided. The lack of available frequencies in the 2-7 mc range, together with the comparatively poorer grade of facility obtained from these radio systems, makes it desirable to investigate other methods of providing telephone facilities. The fact that the present Miami-Havana tropospheric scatter system is performing so well, and that the distance from Miami to Nassau is the same as that to the Cuban terminal, made this type of system very attractive. At the time the Cuban system was being developed, klystron tubes capable of high outputs above 1000 mc were not available. For this reason, the Cuban system was designed to operate in the 700-900 mc range. Since that time tubes capable of high output levels at frequencies above 2000 mc have been developed, and it was considered desirable to operate at these higher frequencies rather than in the lower part of the UHF spectrum. Path loss tests were made over a nineweek period on the Florida-Nassau path using a frequency of 1970 mc. These tests are discussed and some comparisons are drawn between them and the path loss tests made to Cuba at 800 mc two years earlier. The Nassau tests indicated that a satisfactory 60-channel radio system could be provided through use of 10-kw transmitters and 30-foot parabolic antennas.","PeriodicalId":154431,"journal":{"name":"IRE Transactions on Communications Systems","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1959-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130062099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Choosing the Optimum Type of Modulation - A Comparison of Several Communication Systems","authors":"G. Kelley","doi":"10.1109/TCOM.1958.1097522","DOIUrl":"https://doi.org/10.1109/TCOM.1958.1097522","url":null,"abstract":"The engineer designing a new communications system often has available a choice between several different types of RF modulation. The four main methods considered here are standard amplitude (AM), double-sideband suppressedcarrier (DSBSC), single-sideband (SSB), and frequency (FM) modulations. Some of their basic system performance characteristics are evaluated on a comparative basis for the transmission of voice and pulsed data. Factors considered include: compatibility, effective range, bandwidth, signal-to-noise performance, interference rejection capabilities, distortion characteristics, required stability, required transmitter power, and resulting circuit complexity. The choice of the best type of modulation for a particular communications system requires the simultaneous consideration of many such factors evaluated for the basic requirements of that system. Because these factors vary with system parameters and because they may be of differing relative importance, it is not possible to say that any one type of modulation is best for all uses. The practical manner in which the choice may be made is illustrated by examples drawn from several types of communication systems.","PeriodicalId":154431,"journal":{"name":"IRE Transactions on Communications Systems","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1958-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121219525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Air-Ground Communications - The ANDB System Development Plan","authors":"B. Montgomery","doi":"10.1109/TCOM.1956.1097286","DOIUrl":"https://doi.org/10.1109/TCOM.1956.1097286","url":null,"abstract":"The Air Navigation Development Board recently established its System Engineering Advisory Team to aid the Director in formulating and carrying out a unified program of research and development for the common system of air navigation and traffic control. This group began its work in the summer of 1955. The goal of ANDB is to secure a system design of air navigation and traffic control that permits a free movement of all types of aircraft as desired by their operators. In this program, the communications system is treated as a tool of air traffic control and its characteristics are dependent on basic air traffic control principles and practices. The program is divided into two broad phases: short term, and long term. The short term portion is aimed at achieving a system design based on currently available equipment and techniques. The long term goal is directed toward the design of a system capable of completely automatic operation. When an advanced system design has been achieved, it is essential that a carefully planned evolutionary transition be available to permit going from the old to the new. As far as can be seen in the future, the ATC system, both in the air and on the ground, will be heterogeneous in nature. That is, old and new equipment must operate compatibly together in the system. There is a considerable history of communications planning in post-war aeronautical studies. Several authoritative plans for air-ground communications systems are contrasted to show a need for better coordination and consistency in planning.","PeriodicalId":154431,"journal":{"name":"IRE Transactions on Communications Systems","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1956-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126749082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Global Public Telephone Service - 1958","authors":"D. Donald, T. Chandler","doi":"10.1109/ee.1959.6445925","DOIUrl":"https://doi.org/10.1109/ee.1959.6445925","url":null,"abstract":"At the Symposium of Global Communications in Washington, DC in June, 1954, the author presented a paper discussing the global public telephone service as provided by the American Telephone and Telegraph Company (AT&T). It is proposed here to review some aspects of public telephone service in the light of the important developments that have taken place since then.","PeriodicalId":154431,"journal":{"name":"IRE Transactions on Communications Systems","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124513116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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