HF Communications

HF Communications PDF

Author: Nicholas M Maslin

Publisher: CRC Press

Published: 2017-06-30

Total Pages: 256

ISBN-13: 0203168895

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Communications using the high frequency spectrum (2-30 MHz) have experienced a considerable resurgence. In recent years, powerful microcomputers and VLSI technology have greatly enhanced the prospects of overcoming many of the unique problems that formerly afflicted the HF systems More...designer. The aim of this book, therefore, is to provide a fi

HF Communications Systems and Technology

HF Communications Systems and Technology PDF

Author: John M. Goodman

Publisher: Springer

Published: 1992-05-28

Total Pages: 664

ISBN-13:

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Communications engineers, ionospheric scientists, engineers and scientists in DoD HF projects, and DoD managers will use this source to gain a working understanding of the basic theory involved in HF radiowave propagation and uses of HF technology today.

Modern HF Signal Detection and Direction Finding

Modern HF Signal Detection and Direction Finding PDF

Author: Jay R. Sklar

Publisher: MIT Press

Published: 2018-09-25

Total Pages: 369

ISBN-13: 0262038293

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Detailed descriptions of detection, direction-finding, and signal-estimation methods, using consistent formalisms and notation, emphasizing HF antenna array sensing applications. Adaptive antenna array technology encompasses many powerful interference suppression approaches that exploit spatial differences among signals reaching a radio receiver system. Today, worldwide propagation phenomenology occurring in the High Frequency (HF) radio regime has made such interference common. In this book, Jay Sklar, a longtime researcher at MIT Lincoln Laboratory, presents detailed descriptions of detection, direction-finding, and signal-estimation methods applicable at HF, using consistent formalisms and notation. Modern electronic system technology has made many of these techniques affordable and practical; the goal of the book is to offer practicing engineers a comprehensive and self-contained reference that will encourage more widespread application of these approaches. The book is based on the author's thirty years of managing MIT Lincoln Laboratory work on the application of adaptive antenna array technologies to the sensing of HF communication signals. After an overview of HF propagation phenomenology, communication signal formats, and HF receiver architectural approaches, Sklar describes the HF propagation environment in more detail; introduces important modulation approaches and signaling protocols used at HF; discusses HF receiver system architectural features; and addresses signal processor architecture and its implementation. He then presents the technical foundation for the book: the vector model for a signal received at an adaptive array antenna. He follows this with discussions of actual signal processing techniques for detection and direction finding, including specific direction-finding algorithms; geolocation techniques; and signal estimation.

High Frequency Communication and Sensing

High Frequency Communication and Sensing PDF

Author: Ahmet Tekin

Publisher: CRC Press

Published: 2018-09-03

Total Pages: 152

ISBN-13: 1482207125

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High Frequency Communication and Sensing: Traveling-Wave Techniques introduces novel traveling wave circuit techniques to boost the performance of high-speed circuits in standard low-cost production technologies, like complementary metal oxide semiconductor (CMOS). A valuable resource for experienced analog/radio frequency (RF) circuit designers as well as undergraduate-level microelectronics researchers, this book: Explains the basics of high-speed signaling, such as transmission lines, distributed signaling, impedance matching, and other common practical RF background material Promotes a dual-loop coupled traveling wave oscillator topology, the trigger mode distributed wave oscillator, as a high-frequency multiphase signal source Introduces a force-based starter mechanism for dual-loop, even-symmetry, multiphase traveling wave oscillators, presenting a single-loop version as a force mode distributed wave antenna (FMDWA) Describes higher-frequency, passive inductive, and quarter-wave-length-based pumped distributed wave oscillators (PDWOs) Examines phased-array transceiver architectures and front-end circuits in detail, along with distributed oscillator topologies Devotes a chapter to THz sensing, illustrating a unique method of traveling wave frequency multiplication and power combining Discusses various data converter topologies, such as digital-to-analog converters (DACs), analog-to-digital converters (ADCs), and GHz-bandwidth sigma-delta modulators Covers critical circuits including phase rotators and interpolators, phase shifters, phase-locked loops (PLLs), delay-locked loops (DLLs), and more It is a significantly challenging task to generate and distribute high-speed clocks. Multiphase low-speed clocks with sharp transition are proposed to be a better option to accommodate the desired timing resolution. High Frequency Communication and Sensing: Traveling-Wave Techniques provides new horizons in the quest for greater speed and performance.

Siting Criteria for HF Communication Centers

Siting Criteria for HF Communication Centers PDF

Author: William F. Utlaut

Publisher:

Published: 1962

Total Pages: 48

ISBN-13:

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This note is intended to provide an engineering guide for the siting radio terminals for use in long-range HF communication systems. A brief summary of ionospheric effects upon HF radio signals is presented. Various factors required for an ideal site such as Fresnel zone size and smoothness, noise, antenna height, vertical radiation angle and electrical characteristics of the ground are discussed. Standards to guide compromises for practical cases of siting are considered. A partial bibliography which may be useful for those desiring a greater depth of understanding of the various subjects considered in provided.