National Academy of Sciences National Research Council

Total Page:16

File Type:pdf, Size:1020Kb

National Academy of Sciences National Research Council NATIONAL ACADEMY OF SCIENCES NATIONAL RESEARCH COUNCIL of the UNITED STATES OF AMERICA UNITED STATES NATIONAL COMMITTEE International Union of Radio Science I ( 1975 Annual Meeting October 20-23 Sponsored by USNC/URSI in cooperation with Institute of Electrical and Electronics Engineers University of Colorado Boulder, Colorado Price $3.00 URSI/USNC 1975 Annual Meeting Condensed Technical Program Sunday, October 19 2000-2400 U.S. National Committee Meeting Sheraton Monda October 20 II-1 M~ning Communications UMC 159 III-1 Ionospheric Radio Scintillations - I UMC 156 IV-1 VLF/ELF Active and Passive Probing UMC 157 V-1/I, II, VII Extra-Terrestrial Techniques for Measuring Crustal Motions and Satellite Ranging UMC W Blrm 0900-1200 VI-1 Scattering - I RB Aud. VI-2 Antennas RB 1107 VIII-1/I Noise and Interference Measurements UMC F.R. B-la/I Auditory Effects UMC E Blrm B-lb/I Microwave Cataractogenisis UMC E Blrm 1330-1700 Combined Session UMC C Blrm 2000-2200 Evening Lecture UMC C Blrm Tuesda October 21 II-2 Sub-Surface Propagation and Communications UMC 159 1 II-3 Radio Oceanography Seasat "A ' UMC F.R. III-2 Ionospheric Radio Scintillations - II UMC 157 IV-2 Plasma Instabilities in the Magnetosphere - I UMC 158 V-2 Millimeter Wavelength Techniques UMC 156 0830-1200 VI-3 Numerical Techniques RB 1107 VI-4 Integrated and Fiber Optics - I RB Aud. VIII-2/VI Noise and Interference Models and Radio System Planning RB 1103 B-2a/I Therapeutic Applications UMC W Blrm B-2b/I Diagnostic Applications UMC W Blrm B-3/I Field Survey Instruments UMC E Blrm I-1 Measurements and Techniques RB 1103 IV-3 Plasma Instabilities in the Magnetosphere - II UMC 158 V-3/III, VIII Interference to Radio Astronomy and CCIR 1330-1700 Related Topics UMC 156 VI-5 Integrated and Fiber Optics - II RB Aud. VI-6 Scattering - II RB 1107 B-4/I Cellular and Mutagenetic Effects UMC W Blrm B-5/I Exposure Systems UMC E ·Blrm II-4 Radio Meteorology--Observations, Measurements, and Theory UMC 159 1330-1630 II-5 Radar Oceanography--Sea Surface Winds and Ocean Waves UMC F.R. III-3 Observation of Spatial and Temporal Structure of', the Ionosphere - I UMC 157 1645-1845 Commission II Business Meeting UMC 156 Commission III Business Meeting UMC 157 1800-2000 Reception Sheraton Wednesda October 22 II-6 Satellite Communications UMC 159 II-7 Radio Meteorology--Radio Propagation and Wind Measurements in Convective Storms UMC F.R. III-4 Observation of Spatial and Temporal Structure of the Ionosphere - II UMC 157 IV-4 Precipitation and Plasmas UMC 158 V-4 Galactic and Extragalactic Observations UMC 156 0830-1200 VI-7/I Inverse Scattering RB Aud. VI-8/VIII Topics in Communication Theory RB 1107 B-6a/I Behavioral Effects (Low Level Exposure) UMC E Blrm B-6b/I Behavioral Effects (High Level Exposure) UMC E Blrm B-7a/I Assessment of Power Deposition in Tissues by Mathematical and Phantom Models UMC W Blrm B-7b/I Dielectric Properties of Tissues UMC W Blrm Continued on inside back cover United States National Committee INTERNATIONAL UNION OF RADIO SCIENCE PROGRAM AND ABSTRACTS 1975 Annual Meeting October 20-23 Sponsored by USNC/URSI in cooperation with IEEE groups a~d societies: Antennas and Propagation Circuits and Systems Communications Electromagnetic Compatibility Geoscience Electronics Information Theory Instrumentation and Measurement Microwave Theory and Techniques Hosted by: The National Oceanic and Atmospheric Administration The National Bureau of Standards The Institute for Telecommunication Sciences Office of Telecommunications The University of Colorado The Denver Section, IEEE and The Denver-Boulder Chapter, IEEE/APS Boulder, Colorado NOTE: Programs and Abstracts of the USNC/URSI Meetings are available from: USNC/URSI National Academy of Sciences 2101 Constitution Avenue, N.W. Washington, D.C. 20418 The full papers are not published in any collected format; requests for them should be addressed to the authors who may have them published on their own initiative. Please note that these meetings are national and are not organ­ ized by international URSI, nor are these programs avail­ able from the international Secretariat. ii MEMBERSHIP United States National Connnittee INTERNATIONAL UNION OF RADIO SCIENCE Chairman: F.S. Johnson, University of Texas, Dallas Vice Chairman: J.V. Evans, Lincoln Laboratory, M.I.T. Secretary: C.G. Little, Environmental Research Labs, NOAA Editor: T.B.A. Senior, University of Michigan Immediate Past Chairman: A.T. Waterman, Jr., Stanford University Commission Chairmen: Connnission I: Radio Measurements and Standards George Birnbaum National Bureau of Standards Building 223, Room B 354 Washington, D.C. 20234 Connnission II: Radio and Nonionized Media Isadore Katz Applied Physics Laboratory The Johns Hopkins University 8621 Georgia Avenue Silver Springs, Maryland 20910 Commission III: On the Ionosphere John M. Kelso ITT Electro-physics Labs, Inc. 9140 Old Annapolis Road Columbia, Maryland 21043 Commission IV: On the Magnetosphere Andrew F. Nagy Dept. of Electrical Engineering University of Michigan Ann Arbor, Michigan 48104 Connnission V: Radio and Radar Astronomy Alan H. Barrett Research Laboratory of Electronics (26-457) Massachusetts Institute of Technology Cambridge, Massachusetts 02139 iii Commission VI: Radio Waves and Transmission of Information Aharon A. Ksienski ElectroScience Laboratory The Oh"io State University 1320 Kinnear Road Columbus, Ohio 43212 Commission VIII: Radio Noise and Interference George H. Hagn Stanford Research Institute 1611 North Kent Street Arlington, Virginia 22209 Persons Taking Office, January 1, 1976: Chairman: J.V. Evans, Lincoln Laboratory, M.I.T. Vice Chairman: C.G. Little, Environmental Research Labs, NOAA Secretary: J.R. Wait, U.S. Department of Commerce, Boulder Editor: T,B,A. Senior, University of Michigan Commission Chairmen: Commission I: George E. Schafer Commission II: Alfred H. LaGrone Commission III: Thomas. E. Vanzandt Commission IV: Peter M. Banks Commission V: Kenneth I. Kellerman Commission VI: Thomas B.A. Senior Commission VIII: George H. Hagn Members at Large: P.M. Banks E.E. Gossard C, I. Beard A. Ishimaru W.C. Erickson J.S. Nisbet L.B. Felsen W.F. Utlaut Officers of URS! resident in the United States: Honorary President: s. Silver Chairman, Commission I(A): H.M. Altschuler Chairman, Commission V(J): G. Westerhout Vice Chairman, Commission IV(H): F.W. Crawford Vice Chairman, Commission VI (B): L.B. Felsen Vice Chairman, Commission VIII(E): G.H. Hagn Vice Chairman, Commission II (F): A.T. Waterman iv American Geophysical Union: A.J. Dessler IEEE: E. Weber United States Government: Department of Commerce: A.H. Shapley Department of Defense: E. Paroulek Air Force: D.J. Sletten Army: A.R. Rasmussen: Navy: A.H. Schooler FCC: H. Fine NASA: E.R. Schmerling NSF: R.M. Price OTP: W. Dean, Jr. Foreign Secretary, NAS: G.S. Hammond Chairman, NRC Office of Physical Sciences: D.A. Bromley Honorary Members: R.H. Beverage A.H. Waynick V DESCRIPTION OF INTERNATIONAL UNION OF RADIO SCIENCE The International Union of Radio Science is one of 17 world scientific unions organized under the Interna­ tional Council of Scientific Unions (ICSU). It is com­ monly designated as URSI (from its French name, Union Radio Scientifique Internationale). Its aims are (1) to promote the scientific study of radio communications, (2) to aid and organize radio research requiring coopera­ tion on an international scale and to encourage the dis­ cussion and publication of the results, and (3) to facil­ itate agreement upon common methods of measurement and the standardization of measuring instruments. The Inter­ national Union itself is an organizational framework to aid in promoting these objectives. The actual technical work is largely done by the National Committees in the various countries. The officers of the International Union are: President: J. Voge (France) Immediate Past President: W.J.G, Beynon (UK) Vice Presidents: W.N. Christiansen (Australia) W.E. Gordon (USA) V.V. Migulin (USSR) F.L.H.M. Stumpers (Netherlands) Secretary General: C.M. Minnis (Belgium) Honorary Presidents: B. Decaux (France) W. Dieminger (West Germany) C. Manneback (Belgium) J.A. Ratcliffe (UK) S. Silver (USA) R.L. Smith-Rose (UK) The Secretary's office and the headquarters of the organization are located at 7 Place Emile Danco, 1180 Brussels, Belgium. The Union is supported by contribu­ tions (dues) from 35 member countries. Additional funds for symposia and other scientific activities of the Union are provided by ICSU from contributions received for this purpose from UNESCO. vi The International Union, as of the XVIII General Assembly held in Lima, Peru, August, 1975, has nine bod­ ies called Commissions for centralizing studies in the principal technical fields. The names of the Commissions and the chairmen follow. The roman numerals in parenthe­ ses indicate the designations of the most closely corre­ sponding previously existing Commissions. The listing of Commissions and chairmen of the United States National Committee in this digest uses the old designations, but formal consideration of the United States ,Commissions by the United States National Committee is pending. A, Electromagnetic Metrology (I) Altschuler (USA) B. Fields and Waves (VI) van Bladel (Belgium) C. Signals and Systems (VI) Picinbono (France) D. Physical Electronics (VII) Smolinski (Poland) E. Interference Environment (VIII) Likhter (USSR) F. Wave Phenomena in Nonionized Media (II) Eklund (Sweden) G. Ionospheric Radio (III) King (United Kingdom) H. Waves in Plasmas (IV) Gendrin (France) J. Radio Astronomy (V) Westerhout (USA) Every three years, the International Union holds a meeting called the General Assembly. The next General Assembly, the XIX, will be held in Helsinki, Finland in August 1978. The Secretariat prepares and distributes the Proceedings of these General Assemblies. The Inter­ national Union arranges international symposia on specif­ ic subjects pertaining to the work of one Commission or to several Commissions. The International Union also cooperates with other Unions in international symposia on subjects of joint interest.
Recommended publications
  • Spectrum Management Technical Handbook
    NTIA TN 89-2 SPECTRUM MANAGEMENT TECHNICAL HANDBOOK TECHNICAL NOTE SERIES NTIA TECHNICAL NOTE 89-2 SPECTRUM MANAGEMENT TECHNICAL HANDBOOK l U.S. DEPARTMENT OF COMMERCE Robert A. Mosbacher, Secretary Alfred C. Sikes, Assistant Secretary for Communications and Information JULY 1989 ACKNOWLEDGEMENT NT IA acknowledges the efforts of Mark Schellhammer in the completion of Phase I of this handbook (Sections 1-3). Other portions will be added as resources are available. ABSTRACT This handbook is a compilation of the procedures, definitions, relationships and conversions essential to electromagnetic compatibility analysis. It is intended as a reference for NTIA engineers. KEY WORDS CONVERSION FACTORS COUPLING EQUATIONS DEFINITIONS ·TECHNICAL RELATIONSHIPS iii TABLE OF CONTENTS Subsection Page SECTION 1 TECHNICAL TERMS:DEFINITIONS AND NOTATION TERMS AND DEFINITIONS . .. .. 1-1 GLOSSARY OF STANDARD NOTATION . .. 1-13 SECTION 2 TECHNICAL RELATIONSHIPS AND CONVERSION FACTORS INTRODUCTION . .. .. .. 2-1 TRANSMISSION LOSS FOR RADIO LINKS . �. .. .. 2-1 Propagation Loss . .. .. .. 2-1 Transmission Loss ........................................ 2-2 Free-Space Basic Transmission Loss .......................... 2-2 Basic Transmission Loss .................................... 2-2 Loss Relative to Free-Space .................................. 2-2 System Loss . .. 2-3 ; Total Loss . .. .. 2-3 ANTENNA CHARACTERISTICS . .. 2-3 Antenna Directivity ........................................ 2-3 Antenna Gain and Efficiency .................................. 2-3 I
    [Show full text]
  • University of Iowa Instruments in Space
    University of Iowa Instruments in Space A-D13-089-5 Wind Van Allen Probes Cluster Mercury Earth Venus Mars Express HaloSat MMS Geotail Mars Voyager 2 Neptune Uranus Juno Pluto Jupiter Saturn Voyager 1 Spaceflight instruments designed and built at the University of Iowa in the Department of Physics & Astronomy (1958-2019) Explorer 1 1958 Feb. 1 OGO 4 1967 July 28 Juno * 2011 Aug. 5 Launch Date Launch Date Launch Date Spacecraft Spacecraft Spacecraft Explorer 3 (U1T9)58 Mar. 26 Injun 5 1(U9T68) Aug. 8 (UT) ExpEloxrpelro r1e r 4 1915985 8F eJbu.l y1 26 OEGxOpl o4rer 41 (IMP-5) 19697 Juunlye 2 281 Juno * 2011 Aug. 5 Explorer 2 (launch failure) 1958 Mar. 5 OGO 5 1968 Mar. 4 Van Allen Probe A * 2012 Aug. 30 ExpPloiorenre 3er 1 1915985 8M Oarc. t2. 611 InEjuxnp lo5rer 45 (SSS) 197618 NAouvg.. 186 Van Allen Probe B * 2012 Aug. 30 ExpPloiorenre 4er 2 1915985 8Ju Nlyo 2v.6 8 EUxpKlo 4r e(rA 4ri1el -(4IM) P-5) 197619 DJuenc.e 1 211 Magnetospheric Multiscale Mission / 1 * 2015 Mar. 12 ExpPloiorenre 5e r 3 (launch failure) 1915985 8A uDge.c 2. 46 EPxpiolonreeerr 4130 (IMP- 6) 19721 Maarr.. 313 HMEaRgCnIe CtousbpeShaetr i(cF oMxu-1ltDis scaatelell itMe)i ssion / 2 * 2021081 J5a nM. a1r2. 12 PionPeioenr e1er 4 1915985 9O cMt.a 1r.1 3 EExpxlpolorerer r4 457 ( S(IMSSP)-7) 19721 SNeopvt.. 1263 HMaalogSnaett oCsupbhee Sriact eMlluitlet i*scale Mission / 3 * 2021081 M5a My a2r1. 12 Pioneer 2 1958 Nov. 8 UK 4 (Ariel-4) 1971 Dec. 11 Magnetospheric Multiscale Mission / 4 * 2015 Mar.
    [Show full text]
  • A Novel Ship Target Detection Algorithm Based on Error Self-Adjustment Extreme Learning Machine and Cascade Classifier
    Cognitive Computation (2019) 11:110–124 https://doi.org/10.1007/s12559-018-9606-5 A Novel Ship Target Detection Algorithm Based on Error Self-adjustment Extreme Learning Machine and Cascade Classifier Wandong Zhang1,2 · Qingzhong Li1 · Q. M. Jonathan Wu2 · Yimin Yang3 · Ming Li1 Received: 30 June 2018 / Accepted: 10 October 2018 / Published online: 24 October 2018 © Springer Science+Business Media, LLC, part of Springer Nature 2018 Abstract High-frequency surface wave radar (HFSWR) has a vital civilian and military significance for ship target detection and tracking because of its wide visual field and large sea area coverage. However, most of the existing ship target detection methods of HFSWR face two main difficulties: (1) the received radar signals are strongly polluted by clutter and noises, and (2) it is difficult to detect ship targets in real-time due to high computational complexity. This paper presents a ship target detection algorithm to overcome the problems above by using a two-stage cascade classification structure. Firstly, to quickly obtain the target candidate regions, a simple gray-scale feature and a linear classifier were applied. Then, a new error self-adjustment extreme learning machine (ES-ELM) with Haar-like input features was adopted to further identify the target precisely in each candidate region. The proposed ES-ELM includes two parts: initialization part and updating part. In the former stage, the L1 regularizer process is adopted to find the sparse solution of output weights, to prune the useless neural nodes and to obtain the optimal number of hidden neurons. Also, to ensure an excellent generalization performance by the network, in the latter stage, the parameters of hidden layer are updated through several iterations using L2 regularizer process with pulled back error matrix.
    [Show full text]
  • Transmitter T (X) Channel E (X) Receiver R
    Analog Communication ( 10EC53 ) Introduction The function of the communication system is to make available at the destination a signal originating at a distant point. This signal is called the desired signal. Unfortunately, during the passage of the signal through the channel and front-end of the receiver, this desired signal gets corrupted by a number of undesired signals. This is referred to as Noise. Noise is any unknown or unwanted signal. Noise is the static you hear in the speaker when you tune any AM or FM receiver to any position between stations. It is also the snow or confetti that is visible on a TV screen. The received signal is modeled as r (t) = s (t) + n (t) Where s (t) is the transmitted/desired signal n (t) is the additive noise/unwanted signal The signal n (t) gets added at the channel. It disturbs the transmission and processing of signal in Communication System. Over which one cannot have a control. In general term it is an unwanted signal that affects a wanted signal. It is a random signal that cannot be represented with a simple equation. But some time can be deterministic components (power supply hum, certain oscillations).Deterministic Components can be eliminated by proper shielding and introduction of notch filters. If their were no noise perfect communication would be possible with minimum transmitted power. At the receiver only amplification of the signal power to the desired level is required. If R (x)=T (x) then e (x)=0 Transmitter Receiver T (x) R (x) If R (x) ≠ T (x) then e (x) ≠ 0.The received signal is corrupted.
    [Show full text]
  • Demodulation, Bit-Error Probability and Diversity Arrangements
    RADIO SYSTEMS – ETIN15 Lecture no: 6 Demodulation, bit-error probability and diversity arrangements Anders J Johansson, Department of Electrical and Information Technology [email protected] 5 April 2017 1 Contents • Receiver noise calculations [Covered briefly in Chapter 3 of textbook!] • Optimal receiver and bit error probability – Principle of maximum-likelihood receiver – Error probabilities in non-fading channels – Error probabilities in fading channels • Diversity arrangements – The diversity principle – Types of diversity – Spatial (antenna) diversity performance 5 April 2017 2 RECEIVER NOISE 5 April 2017 3 Receiver noise Noise sources The noise situation in a receiver depends on several noise sources Noise picked up Wanted by the antenna signal Output signal Analog Detector with requirement circuits on quality Thermal noise 5 April 2017 4 Receiver noise Equivalent noise source To simplify the situation, we replace all noise sources with a single equivalent noise source. Wanted How do we determine Noise free signal N from the other sources? N Output signal C Analog Detector with requirement circuits on quality Noise free Same “input quality”, signal-to-noise ratio, C/N in the whole chain. 5 April 2017 5 Receiver noise Examples • Thermal noise is caused by random movements of electrons in circuits. It is assumed to be Gaussian and the power is proportional to the temperature of the material, in Kelvin. • Atmospheric noise is caused by electrical activity in the atmosphere, e.g. lightning. This noise is impulsive in its nature and below 20 MHz it is a dominating. • Cosmic noise is caused by radiation from space and the sun is a major contributor.
    [Show full text]
  • Signal to Noise Ratio (SNR Or S/N) SNR Is the Ratio of the Signal Power to Noise Power
    JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY KAKINADA KAKINADA – 533 001 , ANDHRA PRADESH GATE Coaching Classes as per the Direction of Ministry of Education GOVERNMENT OF ANDHRA PRADESH Analog Communication 26-05-2020 to 06-07-2020 Prof. Ch. Srinivasa Rao Dept. of ECE, JNTUK-UCE Vizianagaram Analog Communication-Day 7, 01-06-2020 Presentation Outline Noise: • Noise and its types • Thermal Noise • Parameters of Noise • Noise in Baseband Communication systems • Gaussian process and NB Noise • Problems 02-06-2020 Prof.Ch.Srinivasa Rao, JNTUK UCEV 2 Learning Outcomes • At the end of this Session, Student will be able to: • LO 1 : Fundamental aspects of Noise • LO 2 : Different Noise types and its Paraneters • LO 3 : Gaussian Process and ND Noise 02-06-2020 Prof.Ch.Srinivasa Rao, JNTUK UCEV 3 Noise Definitions of Noise: • Noise is unwanted signal that affects wanted signal. • Noise can broadly be defined as any unknown signal that affects the recovery of the desired signal. • Noise is an unwanted signal, which interferes with the original message signal and corrupts the parameters of the message signal. This alteration in the communication process, leads to the message getting altered. It most likely enters at the channel or the receiver. Effect of noise • Degrades system performance (Analog and digital) • Receiver cannot distinguish signal from noise • Efficiency of communication system reduces Most common examples of noise are: • Hiss sound in radio receivers • Buzz sound amidst of telephone conversations • Flicker in television receivers, Noise Sources External Internal Noise Noise Atmospheric Industrial Extraterrestrial Solar Noise Cosmic Noise External Noise : • It is due to Man- made and natural resources • Sources over which we have no control such as thunders, snow fall, lightning etc.
    [Show full text]
  • CALIFORNIA STATE UNIVERSITY, NORTHRIDGE SPACE COMMUNICATION THEORY and PRACTICE a Graduate Project Submitted in Partial Satisfac
    CALIFORNIA STATE UNIVERSITY, NORTHRIDGE SPACE COMMUNICATION THEORY AND PRACTICE A graduate project submitted in partial satisfaction of the requirements for the degree of the Masterr of Science 1n Engineering by Kristine Patricia Maine January, 1983 The project of Kristine Patricia Maine is approved: CDr. Ste~en A. Gad~ski) (Dr. ~y H. Pettit, Chair) California State University, Northridge ii ACKNOWLEDGEMENTS A deep sense of gratitude is expressed to my academic advisor, Dr. Ray Pettit, for his invaluable counsel and advisement during the course of this study. In addition, I express thanks to The Aerospace Corporation for the use of their facilities and personnel for the completion of this document. iii TABLE OF CONTENTS Title Page Acknowledgement iii Table of Figures v List of Tables vii List of Symbols viii Abstract xi I. Introduction 1 II. Space Communication System Components 2 III. Theory of Link Analysis 8 IV. Applications of Link Analysis 21 v. Summary 41 Appendix A--Signal Losses 45 Appendix B--Space Shuttle Design Model 54 Appendix C--Communication Satellite Systems 62 Footnotes 67 Bi biliography 70 iv TABLE OF FIGURES Figure Number Title 1 Simplified Transponder Block Diagram 3 Showing a Single Channel Transponder 2 TWT Characteristics 4 3 Typical Antenna Beamwidth Pattern 7 4 Satellite Communication System 9 5 Uplink Model 10 6 Downlink Model 13 7 Satellite Communication Transmitter­ 16 to-Receiver with Typical Loss and Noise Sources 8 Zenith Attenuation Values Expected to 18 be Exceeded 2% of the Year at Mid­ latitudes 9 Probability
    [Show full text]
  • Dr. Dharmendra Kumar Assistant Professor Department of Electronics and Communication Engineering MMM University of Technology, Gorakhpur–273010
    Dr. Dharmendra Kumar Assistant Professor Department of Electronics and Communication Engineering MMM University of Technology, Gorakhpur–273010. Content of Unit-3 Noise: Source of Noise, Frequency domain, Representation of noise, Linear Filtering of noise, Noise in Amplitude modulation system, Noise in SSB-SC,DSB and DSB-C, Noise Ratio, Noise Comparison of FM and AM, Pre- emphasis and De-emphasis, Figure of Merit. Claude E. Shannon conceptualized the communication theory model in the late 1940s. It remains central to communication study today. Noise is random signal that exists in communication systems Channel is the main source of noise in communication systems Transmitter or Receiver may also induce noise in the system There are mainly 2-types of noise sources Internal noise source (are mainly internal to the communication system) External noise source Noise is an inconvenient feature which affects the system performance. Following are the effects of noise Degrade system performance for both analog and digital systems Noise limits the operating range of the systems Noise indirectly places a limit on the weakest signal that can be amplified by an amplifier. The oscillator in the mixer circuit may limit its frequency because of noise. A system’s operation depends on the operation of its circuits. Noise limits the smallest signal that a receiver is capable of processing The receiver can not understand the sender the receiver can not function as it should be. Noise affects the sensitivity of receivers: Sensitivity is the minimum amount of input signal necessary to obtain the specified quality output. Noise affects the sensitivity of a receiver system, which eventually affects the output.
    [Show full text]
  • VLF Wave Injection Into the Magnetosphere from Siple Station
    VOL. 79, NO. 16 JOURNAL OF GEOPHYSICAL RESEARCH JUNE I, 1974 VLF Wave Injection Into the MagnetosphereFrom Siple Station, Antarctica R. A. HELLIWELL AND J.P. KATSUFRAKIS RadioscienceLaboratory, Stanford University,Stanford, California 94305 Radio signalsin the 1.5- to 16-kHz range transmittedfrom Siple Station, Antarctica (L = 4), are used to control wave-particleinteractions in the magnetosphere.Observations at the conjugatepoint show signalgrowth and triggeredemissions including risers, failers, and hooks. Growth ratesof the order of 100 dB/s and total gainsup to 30 dB are observed.Triggered emissions may be cut off or havetheir fre- quencyrate of changealtered by Siplepulses. Similar effectsoccur in associationwith harmonicsfrom the Canadianpower system. The observedtemporal growth is predictedby a recentlyproposed feedback model of cyclotroninteraction. Plasma instability theories predicting only spatialgrowth are not in ac- cord with these observations.Possible applications include study of nonlinear plasma instability phenomena,diagnostic measurements of energeticparticles trapped in the magnetosphere,modification of the ionosphere through control of precipitation, and VLF communication through the magnetosphere. This is a report of the first resultsof a new experimentto plasma instability. To obtain further experimental data, a control wave-particleinteractions in the magnetosphere,us- transmitter was neededthat could operate at lower frequen- ing VLF waves.Coherent whistlermode signalswere injected cies and whose power, pulse length, and frequency could into the magnetospherein the 1.5- to 16.0-kHz range from a easily be varied. 100-kW transmitter located at Siple Station, Antarctica. The The next step was constructionof a 33.6-km-long horizon- output signalswere observedat the Sipleconjugate point near tal dipole at Byrd Station (L = 7.25) in 1965 [Guy, 1966].
    [Show full text]
  • Impact of Power Line Telecommunication Systems on Radiocommunication Systems Operating in the LF, MF, HF and VHF Bands Below 80 Mhz
    Report ITU-R SM.2158 (09/2009) Impact of power line telecommunication systems on radiocommunication systems operating in the LF, MF, HF and VHF bands below 80 MHz SM Series Spectrum management ii Rep. ITU-R SM.2158 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and licensing declarations by patent holders are available from http://www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be found. Series of ITU-R Reports (Also available online at http://www.itu.int/publ/R-REP/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radiodetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management Note: This ITU-R Report was approved in English by the Study Group under the procedure detailed in Resolution ITU-R 1.
    [Show full text]
  • Annual Report 1955 National Bureau of Standards
    Annual Report 1955 National Bureau of Standards U. S. Department of Commerce UNITED STATES DEPARTMENT OF COMMERCE Sinclair Weeks, Secretary NATIONAL BUREAU OF STANDARDS A. V. Astin, Director Annual Report 1955 National Bureau of Standards Miscellaneous Publication 217 For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. - Price 55 cents Contents Page General Review 1 1.1. Introduction 1 1.2. Technical Activities 2 1.3. Administrative Activities 9 1.4. Publications 11 Research and Development Program 12 2.1. Electricity and Electronics 12 Fundamental electrical units 13, Electrochemistry 14, Improve- ments in measuring techniques 14, Resistor noise 15, Electron tubes 15, Research on electric spark discharge 16, Pole-top failure 16, Design of mutual inductance transducers 16, Marine weather station 16, Special electronic devices 17, Preferred circuits 17, Mechanized production of electronics 18. 2.2. Optics and Metrology 19 Intercomparison of standards 20, Determination of color dif- ferences 20, Glass color standards 21, Spectacle lenses 22, Aviation lighting 23, Refractometry of synthetic crystals 24. 2.3. Heat and Power 24 Temperature standards 25, Low-temperature research 26, Properties of air and related substances 28, Thermodynamic properties of metals and salts 29, Mechanical degradation of polymers 29, Combustion in engines 30. 2.4. Atomic and Radiation Physics 31 Velocity of light redetermined 31, Radiation balance 32, X-ray calorimeter 32, Electron beam extractor 33, New radiochem- istry laboratory 33, Attenuation of gamma rays at oblique incidence 34, Zone melting apparatus 35, International inter- comparison of radiation standards 36, Negative ion research 36. 2.5.
    [Show full text]
  • Design Patterns and Software Techniques for Large-Scale, Open and Reproducible Data Reduction
    DESIGN PATTERNS AND SOFTWARE TECHNIQUES FOR LARGE-SCALE, OPEN AND REPRODUCIBLE DATA REDUCTION by Gijs Jan Molenaar A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy Supervised by Prof. Oleg Smirnov 2021 Contents Abstract v Declaration of Authorship vii Acknowledgements viii Preface x Publications xi Source Code xii 1 History of data reduction pipelines 1 1.1 Introduction . .2 1.2 1930s . .2 1.3 1940s . .2 1.4 1950s . .5 1.5 1960s . .5 1.6 1970s . .7 Zero-generation calibration to first-generation calibration . .8 Astronomical Image Processing System . 10 CANDID . 10 CLEAN . 11 1.7 1980s . 11 Self-calibration and the second generation of calibration algorithms . 13 GIPSY . 13 DWARF..................................... 14 IRAF ...................................... 15 Miriad . 15 1.8 Meanwhile in South Africa . 15 1.9 1990s . 17 AIPS++ . 17 NEWSTAR . 18 The Measurement Set version 1 . 18 The Measurement equation . 19 DIFMAP . 19 1.10 2000s . 19 The Measurement Set version 2 . 19 i CONTENTS ii MeqTrees, third-generation calibration algorithms . 19 Obit....................................... 19 CASA...................................... 20 Casacore . 20 1.11 2010s . 21 Cuisine . 21 Docker...................................... 21 The ALMA pipeline . 21 Common Workflow Language . 22 DDFacet and killMS . 22 Kliko....................................... 22 Stimela . 23 CARACal (formerly known as MeerKATHI) . 23 Default pre-processing pipeline . 23 The LOFAR two-metre survey pipeline . 24 1.12 Overview of events . 25 1.13 Discussion . 27 2 Fundamentals 29 2.1 Electromagnetic radiation . 30 2.2 Interferometry . 33 Aperture synthesis . 34 The (u; v; w) coordinate system . 36 The radio interferometer measurement equation . 37 2.3 Image reconstruction .
    [Show full text]