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ETR 132 TECHNICAL August 1994 REPORT
ETSI ETR 132 TECHNICAL August 1994 REPORT Source: EBU/ETSI JTC Reference: DTR/JTC-00011 ICS: 33.060 Key words: Broadcasting, FM, radio, transmitter, VHF European Broadcasting Union Union Européenne de Radio-Télévision EBU UER Radio broadcasting systems; Code of practice for site engineering Very High Frequency (VHF), frequency modulated, sound broadcasting transmitters ETSI European Telecommunications Standards Institute ETSI Secretariat Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: [email protected] Tel.: +33 92 94 42 00 - Fax: +33 93 65 47 16 Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. © European Telecommunications Standards Institute 1994. All rights reserved. New presentation - see History box © European Broadcasting Union 1994. All rights reserved. Page 2 ETR 132: August 1994 Whilst every care has been taken in the preparation and publication of this document, errors in content, typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to "ETSI Editing and Committee Support Dept." at the address shown on the title page. Page 3 ETR 132: August 1994 Contents Foreword .......................................................................................................................................................7 1 Scope -
Maintenance of Remote Communication Facility (Rcf)
ORDER rlll,, J MAINTENANCE OF REMOTE commucf~TIoN FACILITY (RCF) EQUIPMENTS OCTOBER 16, 1989 U.S. DEPARTMENT OF TRANSPORTATION FEDERAL AVIATION AbMINISTRATION Distribution: Selected Airway Facilities Field Initiated By: ASM- 156 and Regional Offices, ZAF-600 10/16/89 6580.5 FOREWORD 1. PURPOSE. direction authorized by the Systems Maintenance Service. This handbook provides guidance and prescribes techni- Referenceslocated in the chapters of this handbook entitled cal standardsand tolerances,and proceduresapplicable to the Standardsand Tolerances,Periodic Maintenance, and Main- maintenance and inspection of remote communication tenance Procedures shall indicate to the user whether this facility (RCF) equipment. It also provides information on handbook and/or the equipment instruction books shall be special methodsand techniquesthat will enablemaintenance consulted for a particular standard,key inspection element or personnel to achieve optimum performancefrom the equip- performance parameter, performance check, maintenance ment. This information augmentsinformation available in in- task, or maintenanceprocedure. struction books and other handbooks, and complements b. Order 6032.1A, Modifications to Ground Facilities, Order 6000.15A, General Maintenance Handbook for Air- Systems,and Equipment in the National Airspace System, way Facilities. contains comprehensivepolicy and direction concerning the development, authorization, implementation, and recording 2. DISTRIBUTION. of modifications to facilities, systems,andequipment in com- This directive is distributed to selectedoffices and services missioned status. It supersedesall instructions published in within Washington headquarters,the FAA Technical Center, earlier editions of maintenance technical handbooksand re- the Mike Monroney Aeronautical Center, regional Airway lated directives . Facilities divisions, and Airway Facilities field offices having the following facilities/equipment: AFSS, ARTCC, ATCT, 6. FORMS LISTING. EARTS, FSS, MAPS, RAPCO, TRACO, IFST, RCAG, RCO, RTR, and SSO. -
Reception Performance Improvement of AM/FM Tuner by Digital Signal Processing Technology
Reception performance improvement of AM/FM tuner by digital signal processing technology Akira Hatakeyama Osamu Keishima Kiyotaka Nakagawa Yoshiaki Inoue Takehiro Sakai Hirokazu Matsunaga Abstract With developments in digital technology, CDs, MDs, DVDs, HDDs and digital media have become the mainstream of car AV products. In terms of broadcasting media, various types of digital broadcasting have begun in countries all over the world. Thus, there is a demand for smaller and thinner products, in order to enhance radio performance and to achieve consolidation with the above-mentioned digital media in limited space. Due to these circumstances, we are attaining such performance enhancement through digital signal processing for AM/FM IF and beyond, and both tuner miniaturization and lighter products have been realized. The digital signal processing tuner which we will introduce was developed with Freescale Semiconductor, Inc. for the 2005 line model. In this paper, we explain regarding the function outline, characteristics, and main tech- nology involved. 22 Reception performance improvement of AM/FM tuner by digital signal processing technology Introduction1. Introduction from IF signals, interference and noise prevention perfor- 1 mance have surpassed those of analog systems. In recent years, CDs, MDs, DVDs, and digital media have become the mainstream in the car AV market. 2.2 Goals of digitalization In terms of broadcast media, with terrestrial digital The following items were the goals in the develop- TV and audio broadcasting, and satellite broadcasting ment of this digital processing platform for radio: having begun in Japan, while overseas DAB (digital audio ①Improvements in performance (differentiation with broadcasting) is used mainly in Europe and SDARS (satel- other companies through software algorithms) lite digital audio radio service) and IBOC (in band on ・Reduction in noise (improvements in AM/FM noise channel) are used in the United States, digital broadcast- reduction performance, and FM multi-pass perfor- ing is expected to increase in the future. -
Chapter 7 Amplitude Modulation
page 7.1 CHAPTER 7 AMPLITUDE MODULATION Transmit information-b earing message or baseband signal voice-music through a Communications Channel Baseband = band of frequencies representing the original signal for music 20 Hz - 20,000 Hz, for voice 300 - 3,400 Hz write the baseband message signal mt $ M f Communications Channel Typical radio frequencies 10 KHz ! 300 GHz write ct= A cos2f ct c ct = Radio Frequency Carrier Wave A = Carrier Amplitude c fc = Carrier Frequency Amplitude Mo dulation AM ! Amplitude of carrier wavevaries a mean value in step with the baseband signal mt st= A [1 + k mt] cos 2f t c a c Mean value A . c 31 page 7.2 Recall a general signal st= at cos[2f t + t] c For AM at = A [1 + k mt] c a t = 0 or constant k = Amplitude Sensitivity a Note 1 jk mtj < 1or [1 + k mt] > 0 a a 2 f w = bandwidth of mt c 32 page 7.3 AM Signal In Time and Frequency Domain st = A [1 + k mt] cos 2f t c a c j 2f t j 2f t c c e + e st = A [1 + k mt] c a 2 A A c c j 2f t j 2f t c c e + e st = 2 2 A k c a j 2f t c + mte 2 A k c a j 2f t c + mte 2 To nd S f use: mt $ M f j 2f t c e $ f f c j 2f t c e $ f + f c expj 2f tmt $ M f f c c expj 2f tmt $ M f + f c c A c S f = [f f +f +f ] c c 2 A k c a + [M f fc+Mf +f ] c 2 33 page 7.4 st = A [1 + k mt] cos 2f t c a c A c = [1 + k mt][expj 2f t+ expj 2f t] a c c 2 If k mt > 1, then a ! Overmo dulation ! Envelop e Distortion see Text p. -
The Marriage That Almost Was Western Union Has Always Been R.Idiculed for Rejecting the All Telephone
RETROSPECTIVE .Innovation The marriage that almost was Western Union has always been r.idiculed for rejecting the telephone. But what actually happened wasn't so ridiculous after all The hirth of the telephone.,-one hundred years ago railway and illuminating gas to Cambridge, Mass. this month-is a fascinating story of the geJ;Jius and Long intrigued by telegraphy, he decided to do persistence of on.e man. In addition, it is an instruc something about what he called "this monopoly tive demonstration of how an industrial giant, in with its inflated capital which serves its stockhold this case the Western Union Telegraph Co., can ers better than the 'public and whose:rates are ex miss its chance to foster an industry-creating orbitant and prohibiting of many kinds of busi breakthrough-something that has happened again ness." Between 1868 and 1874, he lobbied unceas and again in electronics and other fields. ingly, shuttling back and forth betweep. homes in Between ·1875 and 1879, Western Union's chiefs Boston and Washington. for a private "postal tele engaged in an intricate minuet with Alexander graph company" to be chartered by Congress but Graham Bell and his associates. On more than one with Hubbard and some of his friends among the occasion, the telegraph colossus came excruciating incorporators. As Hubbard envisioned it, the com ly close to absorbing the small group of ~ntre pany would build telegraph lines along the nation's preneurs, That the absorption was finally avoided rail and post roads and contract with the Post was probably the result of a technological gamble Office Department to send telegrams on its wires ~t that simply didn't payoff, as rates roughly half those being charged by Western ••• The place: the ollie of well as a clash of personali Union. -
United States Patent [19] [11] Patent Number: 5,410,735 Borchardt Et Al
U SOO54l0735A United States Patent [19] [11] Patent Number: 5,410,735 Borchardt et al. - [45] Date of Patent: Apr. 25, 1995 [54] WIRELESS SIGNAL TRANSMISSION 4,739,413 4/1983 Meyer - SYSTEMS, METHODS AND APPARATUS 4,771,344 9/1988 Fallacaro e141- - 4,847,903 7/1989 Schotz ................................... .. 381/3 [76] Inventors: Robert L. Borchardt, 120 E. End '. ' . ' ' Ave" New York, NY. 10028; _(L1st contlnued on next page.) _ William T. McGreevy, 43 Thompson FOREIGN PATENT DOCUMENTS Ave., Babylon, NY. 11702; Ashok _ Naw ge’ 3L7‘) 34th St.’ Apt.#3F, 0040481 2/1988 Japan .............................. .. 358/194.l Astoria, NY. 11105; Efrain L. OTHER PUBLICATIONS §°d"lf1“ez’§6; Y" “New 902-928 MHZ Band Now Open!”, Spec-Com mo yn’ ' ' Journal, Sep/Oct. 1985, cover page and p. 9. __ [21] Appl. No.: 259,339 Federal Register, vol. 50, Aug. 22, 1985, Final Rulemak . ing re addition of 902-928 MHz band to Amateur Radio [22] E169 J‘m' 13,1994 Service Rules, pp. 33937 through 33940. Related Us. Application Data (List continued on next page.) . - _ Primary Examiner—Reinhard J. Eisenzopf [63] ggéietanuation of Ser. No. 822,598, Jan. 17, 1992, aban Assistant Examiner_Andrew Faile [51] In G 6 H04B 1/00 Attorney, Agent, or Firm-Levisohn, Lerner & Berger t. > ............................................. .. [52] US. Cl. .................................... .. 455/42; 455/110; [571 ABSTRACT 455/205; 455/ 344; 455/ 351 ; 381/3 Systems, methods and apparatus are provided for con [58] Field of Search .................................. .. 455/42-43, ‘ducting local wireless audio signal transmissions from a 455/66, 95, 110-113, 120-125, 205, 208, 214, 'local audio signal source to a person within a local 344, 351, 352, 127, 343; 348/725, 731, 738; signal transmission area. -
ELEC3027 Radio Communications Background Information on Amplitude Modulation
ELEC3027 Radio Communications Background Information on Amplitude Modulation 1 Analogue Modulation 1.1 Amplitude Modulation When a Radio Frequency (RF) signal is placed onto the antenna of a transmitter, it will propagate through free space and can be detected on the antenna of a receiver. The higher the frequency of this signal, the smaller the antennas that are required. However, we are often interested in communicating relatively low frequency message signals, such as audio. Hence, we must modulate our low frequency message signal onto a high frequency carrier, in order to transmit it. This has the added benefit of allowing us to modulate different message signals onto different carrier frequencies, in order to transmit them without interfering with each other. Figure 1 shows the schematic of a transmission scheme that uses Amplitude Modulation (AM) to transmit a time-varying input signal x(t), as well as demodulation to obtain a received signal xˆ(t). Modulator Demodulator A cos(2πfct) x(t) y(t) u(t) xˆ(t) + LPF × Figure 1: AM modulation and demodulation. 1.1.1 Operation The AM modulator of Figure 1 uses the message signal x(t) to vary the amplitude of the carrier sinusoid cos(2πfct), where the carrier frequency fc is usually much higher than the highest frequency in the message signal. As shown in Figure 1 y(t) = [A + x(t)] cos(2πfct), (1) 1 where A is a constant DC offset. In the AM demodulator of Figure 1, the diode symbol represents a rectifier which gives y(t) if y(t) > 0 u(t)= . -
Vintage Radio
VINTAGE RADIO Building a vintage radio "replica" Have you always wanted a 1920s or 1930s lacquer finish of some sort. Second, a glance at the front panel reveals that "cathedral" style radio. They're as scarce as these sets can receive FM transmis- sions as well as AM. In reality, FM hens' teeth these days - or are they? If you didn't get under way in Australia un- can't get an original, what about one of the til well after the era that the "replica" is supposed to represent. many replicas now coming onto the market? However, it's not until you expect the "insides" of such radios that you From time to time, "replicas" of ites but of course, they're not true realise just how far away they are early radio sets appear in catalog ad- replicas. First, the cabinets are noth- from being a true replica of the era. vertisements from various electronics ing like the those from the 20s, 30s Hidden inside the cabinet will be a and electrical retailers. Consoles and and 40s, usually being made from small transistor radio and that's hardly cathedral sets seem to be the favour- cheap ply or particle board with a something that was around in the 1920s or 1930s! So these sets are in no way an accu- rate copy or replica of any early radio. The fact is, there are very few genu- ine 1920s (and not many more 1930s) sets now available on the market. Many collectors will never own ra- dios of this vintage. -
1994-11: Browning-Drake
Vii luta gic IRaidl iio by PETER LANKSHEAR The Browning-Drake receiver One of the best remembered radio names from the 1920's is 'Browning-Drake', a receiver which combined simplicity with what for its time was a rate performance. While most of its contempo- raries had production lives of little more than a year, the Browning-Drake design was popular for much of the decade. As with the IBM personal computer'. it. recently, there were also more 'clones' made by others than the official versions... By the outbreak of World War I, valve cluding them in tuned circuits coupling The alternative method, and of course receiver technology had advanced to the the valves. However the tuned RF ampli- the ultimate solution to many difficulties stage where stable detection and low fre- fier then ran into another problem. Tri- was the superheterodyne, attributed by quency amplification were possible. ode valves have sufficient inter-ekctrode Americans to work done in 1918 by Ma- However there were limitations to the capacitance that with tuned circuits con- jor Edwin Armstrong of the US Army. sensitivity and selectivity of the grid leak nected to both anode and grid, there is While much credit is due to Armstrong, it detectors that had become standard. sufficient energy transferred internally is now clear that the original concept of The newly discovered regeneration back to the grid to cause them to become the superhet was an international effort, helped, but it became clear that the only vigorous oscillators. with much of the early work being done way to improve receiver sensitivity was Initially there were two solutions. -
Man of High Fidelity
Man of High Fidelity: EDWIN HOWARD ARMSTRONG A Biography – By Lawrence Lessing With a new forward by the author Page iii Pratt DISCLAIMER DISCLAIMER TO THIS SCANNED AND OCR PROCESSED COPY This PDF COPY is for use at Pratt Institute for Educational Purposes Only I affirm that sufficient print copies of the original Bantam Book Paperback are in stock in ARC E-08 that would more than adequately cover a full class use of the text. HOWEVER, due to the fact that the 1969 text is no longer in publication, complicated by the fact that these copies are forty-four (44) years old and in a very fragile condition, this PDF version of the text was created for student use in the Department of Mathematics and Science. - Professor Charles Rubenstein, January 2013 Man of High Fidelity: Edwin Howard Armstrong EDWIN HOWARD ARMSTRONG Was the last – and perhaps the least known – of the great American Inventors. Without his major contributions, the broadcasting industry would not be what it is today, and there would be no FM radio. But in time of mushrooming industry and mammoth corporations, the recognition of individual genius is often refused, and always minimized. This is the extraordinary true story of the discovery of high fidelity, the brilliant man and his devoted wife who battled against tremendous odds to have it adopted, and their long fight against the corporations that challenged their right to the credit and rewards. Mrs. Armstrong finally ensured that right nearly ten years after her husband’s death. Page i Cataloging Information Page This low-priced Bantam Book has been completely reset in a type face designed for easy reading, and was printed from new plates. -
A History of Audio Effects
applied sciences Review A History of Audio Effects Thomas Wilmering 1,∗ , David Moffat 2 , Alessia Milo 1 and Mark B. Sandler 1 1 Centre for Digital Music, Queen Mary University of London, London E1 4NS, UK; [email protected] (A.M.); [email protected] (M.B.S.) 2 Interdisciplinary Centre for Computer Music Research, University of Plymouth, Plymouth PL4 8AA, UK; [email protected] * Correspondence: [email protected] Received: 16 December 2019; Accepted: 13 January 2020; Published: 22 January 2020 Abstract: Audio effects are an essential tool that the field of music production relies upon. The ability to intentionally manipulate and modify a piece of sound has opened up considerable opportunities for music making. The evolution of technology has often driven new audio tools and effects, from early architectural acoustics through electromechanical and electronic devices to the digitisation of music production studios. Throughout time, music has constantly borrowed ideas and technological advancements from all other fields and contributed back to the innovative technology. This is defined as transsectorial innovation and fundamentally underpins the technological developments of audio effects. The development and evolution of audio effect technology is discussed, highlighting major technical breakthroughs and the impact of available audio effects. Keywords: audio effects; history; transsectorial innovation; technology; audio processing; music production 1. Introduction In this article, we describe the history of audio effects with regards to musical composition (music performance and production). We define audio effects as the controlled transformation of a sound typically based on some control parameters. As such, the term sound transformation can be considered synonymous with audio effect. -
Cit 305: Networking and Communication Technology
CIT 305: NETWORKING AND COMMUNICATION TECHNOLOGY 1 NATIONAL OPEN UNIVERSITY OF NIGERIA FACULTY OF SCIENCE DEPARTMENT OF COMPUTER SCIENCE COURSE CODE: CIT305 COURSE TITLE: NETWORKING AND COMMUNICATION TECHNOLOGY 2 COURSE GUIDE CIT305 NETWORKING AND COMMUNICATION TECHNOLOGY CourseTeam Prof A.S. Sodiya (Developer/Writer)–FUNAAB Dr. A. A. Afolorunso (Coordinator)-NOUN 3 CONTENTS PAGE Introduction........................................................................................ 1 WhatYouWillLearnin ThisCourse................................................ 1 Course Aims...................................................................................... 1 CourseObjectives…………………………………………….……. 1 WorkingthroughThisCourse............................................................ 2 CourseMaterials................................................................................. 2 2 StudyUnits........................................................................................ AssignmentFile.................................................................................. 3 Tutor-MarkedAssignments(TMAs)................................................. 3 ExaminationandGrading................................................................... 4 PresentationSchedule........................................................................ 4 CourseMarkingScheme.................................................................... 5 CourseOverview…………………………………………………… 5 Howto Getthe MostfromThisCourse...........................................