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A method of bivariate interpolation and smooth surface fitting is developed for z values given at points irregularly distributed in the x-y plane. The interpolating function is a fifth-degree polynomial in x and y defined in each triangular cell whi...

This catalog lists about 495 information products representing the results of the various OT programs. Section I contains an alphabetical listing, by title with abstract and key words, of technical reports, technical memoranda, special publications,...

Atmospheric radio wave propagation in the 40 to 140 GHz band is influenced by microwave spectra of oxygen (O2-MS) and water vapor. The report treats the complementary roles of controlled laboratory experiments and computer analysis for providing deta...

The effects of the atmosphere on radio propagation at frequencies of 10 GHz to 30 GHZ include attenuation and depolarization by precipitation, absorption by water vapor and oxygen, and multipath fading related to refractivity gradients in stratified...

This report summarizes non-government use of Land Mobile Radio. The services provided by LMR are described and the spectrum allocations are outlined. A brief discussion of the present overcrowding of the LMR bands is given along with suggestions that...

Digital data transmission tests using a 12.6 Mb/s data stream (3-level partial response) were performed over a l16-kmline­of-sight link in northeastern Colorado using a carrier fre­quency in the 11.2 -11.45 GHz band. During the first four days of a f...

The papers in this publication were prepared for presentation at technical sales seminars in Yugoslavia, Romania and Poland from Sept. 20 to Oct. 10, 1974. Topics covered include: telecommunications research and development; telephone networks; swit...

A U.S. Postal Service (USPS) electronic message system could incorporate many types of error control coding, or no coding at all. This report reviews a variety of possible codes, lists their advantages and disadvantages, and selects a preferred alte...

This report is a study of the feasibility of applying numerical mapping techniques to the storage and handling of OMEGA propagation corrections. Using the techniques discussed in the report, it is possible to represent the 110,592 propagation corecti...

The continued expansion of microwave radio links and the resulting congestion have increased the need for better performance estimates. In the evaluation of refractivity effects, the designer may wish to consider the average gradients at specific lo...

The extended offshore test range proposed for the Pacific Missile Range will use high altitude aircraft to relay signals for tracking, telemetry, and control. This report treats the reliability of the radio propagation paths between these relays and ...

A theoretical expression for the received signal by a radar is reduced to a utilitarian form by the introduction of feasible first order approximations, and specifying where other common assumptions are made, with concern expressed for the need for e...

Following the alignment and tuning of an analog FM microwave radio to handle a 12.6 Mb/s, 3-level partial response base­band, the effects of various types of interference on system performance were investigated. Since TDM-FM and FDM-FM microwave syst...

A computer procedure called program AREAPOP is used to count the number of persons and housing units within Grade A and Grade B service contours of 294 Public Broadcasting Service television stations in the United States. These population statistics ...

References are presented on the subject of recent (1971 to mid-1974) work on radio propagation through the atmosphere at frequencies from 10 to 100 GHz. The references are separated into six major categories covering propagation through precipitati...

This memorandum is concerned with scintillation effects on digital multiple phase shift keying (MPSK) channels in presence of additive Gaussian noise. The basic channel statistics, such as the correlation bandwidth and related spreads, are introduce...

The Born approximation is used to derive a general expression for a radio wave passing through a random medium. The medium is characterized by a random index of refraction. An explicit transfer function is derived using the Fremouw and Rino model for...

This report considers the minimum bit-rate required for trans­mission of NTSC video color standard when used for tele­conferencing. The smallest values are found for fixed cameras. The use of split screen images will increase the required bit­rate by...

Estimates for the effects on a lateral wave of a clearing in a foliage layer are considered. A first-order solution to the integral equation for the mixed-path problem is derived and two examples are considered. They show that a mid-path clearing ha...

This study concerns ionospheric scintillation as it affects satellite communications between about 100 MHz and 30 GHz. It is divided into three parts. The first part reviews the pertinent physics and suggests some boundaries and values for some of th...