R.M. Fano. / "November 18, 1948." / Bibliography: p. 13. / Army Signal Corps Contract No. W36-039 sc-32037 Project No. 102B. Dept. of the Army Project No. 3-99-10-022.

No description available.

Thesis (Ph.D.)--Washington State University, December 2005. / Includes bibliographical references (p. 79-85).

[by] Arthur B. Baggeroer. / Bibliography: p. 187-191.

M.Tech. (Computer Science) / The Signal Distribution department of the SABC does planning regarding the signal distribution or broadcasting network of the SABC. In order to do effective planning a tool had to be developed to assist in the planning of the broadcasting network. The Rand Afrikaans University was asked to supply a student to analyze the problems surrounding the development of such a tool and supply the SABC with a solution to the problems. The problems surrounding the development of a broadcast network planning model were the availability and accuracy of the information needed for planning. The data needed was spread throughout the country with only manual means to transport the data. The solution to the problem would be to develop a system to cope with the decentralized database and to gather the data in order to supply valuable planning information. To provide a framework for the solution of the planning problem, a broadcasting network was compared with a computer network. The comparison revealed a number of parallels between a broadcasting and a computer network. As a result of the resemblance between the two types of networks, a foundation for the development of a planning model for a broadcasting network could be identified. The ISO IS OSI approach was used as a foundation for the development of the model. The principles of the seven layers along with the three network management models The broadcasting network model was developed using the principles of the OSI approach, object orientation, geographical information systems and graphical user interfaces. A "package" was defined to assist in the logical data flow of the model. The package contains the specific data used in a calculation. A package containing information can be split or combined according to strict rules. The effective management of the package is a central issue in the development of the planning model. A prototype system was developed on PC-Arc/Info, a PC based GIS. The prototype's aim was to prove that the principles used in the model could be implemented successfully. As the developed system was intended to serve as a prototype, it did not implement the full functionality of the model, but only the functions necessary to prove the viability of the model.

No description available.

No description available.

This report presents an initial design effort for a high-speed, constant Frequency data extractor, which can be used to identify and track a particular constant frequency signal in the presence of other signals. Several factors must be included in the design considerations. The detection and acquisition of the correct signal should be accomplished at high speed to remain as close as possible to real time. Once detection has occurred, the system should generate a track-predict gate signal that enables the input line only when the real input pulse is expected. If track is lost, which happens whenever the track-predict gate and input pulse do not occur simultaneously, the initial detection method must be re-entered. The detectable frequency should be selectable over a wide range of values. Furthermore, the system should be able to detect and acquire the desired signal in the presence of large numbers of interfering signals, yet be flexible enough to adapt easily to other pulse modulation methods. Because of the above design factors as well as speed, size, and cost, a high-speed bipolar microprocessor was selected for this system implementation. A microprocessor allows most of the detection and acquisition to be accomplished in the software, thus making the system very adaptable to the host system's requirements.

We develop a general three-stage Moving Average Matched Filter (MAMF) receiver system for digital communications in an environment where the noise conditions are unknown a priori and change constantly and significantly with time. The MAMF is a subset of the class of matched filters which are optimal with respect to enhancing the signal energy relative to the noise power in order to improve discrimination between signals at the receiver. In a time-varying noise environment, a fixed signal cannot be designed and used for transmission which will provide optimal performance at the receiver under all noise conditions. Designing a signal for optimality in a particular noise environment will typically lead to a deteriorated performance in another noise environment relative to a signal which is chosen for the new environment. This deterioration in performance can be so severe that the signal-to-noise ratio (SNR) from the input to the output of the filter is degraded. Ideally, to achieve performance which is more nearly optimal under all noise conditions, the transmitted signal should change or adapt in response to variations in the noise environment. For practical reasons, it is desirable to concentrate all adaptivity in the receiver rather than the transmitter. Typically, a MAMF receiver consists of two stages - a filtering stage and a detection stage. We develop the general design expressions for a three-stage MAMF receiver in which the additional stage is a linear pre-filter placed before the filtering and detection stages. Obviously, if the MAMF is optimal for a given noise condition, any operation performed on the received signal plus noise prior to filtering will potentially reduce performance at that given noise condition by some amount. We accept this performance loss in favor of a pre-filtering operation which can effectively manipulate the transmitted signal upon arrival at the receiver and provide more robust performance in the time-varying noise environment. Specifically, we compare a pre-filter consisting of a unity gain with a prefilter that linearly combines k M x 1 partitions of the transmitted signal vector (i.e. transmitted signal vector of length N = k x M). Proper design of the transmitted signals can ensure that the partitions are linearly independent. In this case, we can view the transmitted signal as representing a k-dimensional subspace of the original M-dimensional signal space. By linearly combining these partitions at the receiver we can achieve any vector within this subspace. We show that we can select these partitions such that the resulting signal vector represents an optimum signal subspace for k noise environments. This is contrasted with the fixed 1-dimensional subspace of the original N-dimensional signal subspace when the pre-filter is a constant gain. The two MAMF receivers are compared by measuring the signal-to-noise ratio improvement (SNRI) of the filters. The SNRI is defined as the output signal-to-noise ratio (OSNR) measured at the output of the filtering stage over the input signal-to-noise ratio (ISNR) measured at the input to the pre-filtering stage. We demonstrate through simulation that the signal subspace version can be more robust with respect to deviation from the absolute maximum SNRI achievable by either system. Using maximum likelihood techniques, we derive an optimal detector for an arbitrary bank of L linear pre-filter and MAMF sections. This is shown to outperform a detection scheme that has been derived for use solely in an optimal binary communication scenario. / Master of Science

Submitted in fulfillment of the academic requirements for the Degree Master of Engineering: Electrical: Electronic Engineering, Durban University of Technology. Durban. South Africa, 2015. / A two element correlating radio telescope interferometer is the fundamental building block of modern radio telescope aperture synthesis arrays. Early radio telescopes consisted of a single antenna, usually a dish antenna. Larger and larger antennas were constructed in order to improve the resolution of the measurement of the direction and extent of radio frequency radiation coming from the sky. Telescope resolution is fundamentally limited by the ratio of the telescope aperture to the wavelength of the received radiation. For single element radio telescopes to approach the resolution of their optical telescope counterparts, they would need to be impractically large. Mathematical analysis of correlating two element radio telescope interferometers shows that very large aperture radio telescopes can be synthesized from a number of two element interferometers. An array of two element correlating radio telescope interferometers can be used to produce a synthesized aperture equal to the largest distance between two receiving antennas in the array. Telescope arrays thus enable very high resolution since the angular resolution of a telescope is proportional to the wavelength of the received signal divided by the aperture diameter. A spread of separation distances between antenna pairs is required to produce a complete image of the radiating sources in the field of view. Modern digital signal processing techniques can be used to provide cost effective performance and flexibility in two element correlating radio telescope interferometer design. The aim of this research project was to design and construct a two element correlating radio telescope interferometer using modern digital signal processing techniques and hardware. The relevant theory has been investigated together with suitable hardware and software platforms and tools used to produce such a system. The two element correlating radio telescope interferometer produced, will be used as a platform for further investigative research into its design, performance and application. The outcome of this research project was the successful completion of a working two element correlating radio telescope interferometer. The development process has been analysed and carefully documented. Some fringe measurements for a simple single frequency radiating point source have been taken and these measurements have been analysed according to theoretical expectation. Potential for further research, using the two element correlating radio telescope interferometer produced, has been identified and discussed.