26 Radio Frequency and Microwave Communication Systems
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ACU-M™ Improving In-Building Communications
Application Note: AN-2306-2 ACU-M™ Improving In-Building Communications Purpose This application note will describe methods in which the Raytheon’s ACU-M can be used to improve in-building communications. The application note will discuss permanent and temporary methods at which different devices can help increase the ability to transmit or receive land mobile radio communications from within a building, below-grade, or behind obstructions. Introduction Land mobile radios, whether used in vehicles or as handheld portables, are an important tool used everyday by first responders to make their jobs safer and more efficient. In the most part, these radio systems function as designed, and serve the end-user with reliable communications. However, when the duties of a first responder require them to enter a building, or operate below- grade during emergencies, the ability of their radios to communicate to the base, incident command or dispatcher may become an issue. One physical constraint of land mobile radio communications is its inability to transmit and receive radio waves through obstructions such as buildings or below-grade structures. The failure of a land mobile radio to transmit and receive communications from within a building or below-grade has cursed radio users since the beginning of land mobile radio communications (see Figure 1). Figure 1: Blockage or Absorption of Low-Power Handheld Radio Transmission Raytheon 5800 Departure Drive Raleigh, NC 27616 919.790.1011 © Raytheon Company. Data is subject to change. http://www.raytheon.com All Trademarks are the property of their respective owners. Application Note: AN-2306-2 Solutions Land mobile radios were first introduced to public safety, in the late 20’s, in the form of shortwave receivers mounted inside patrol vehicles. -
Rs-232 Rs-422 Rs-485
ConceptConcept ofof SerialSerial CommunicationCommunication AgendaAgenda Serial v.s. Parallel Simplex , Half Duplex , Full Duplex Communication RS-485 Advantage over RS-232 SerialSerial v.s.v.s. ParallelParallel Application: How to Measure the temperature in a long distance? Measuring with a DAC card: 1200 m Remote sensor Control room T/C wire T/C A/D noise Application: How to Measure the temperature in a long distance? Measuring with a remote I/O module: 1200 m Remote sensor Control room T/C Remote I/O Standard Serial Communication T/C signal, 4-20mA, 0-5V… Noise rejection (Differential signal) MostMost PopularPopular 33 typestypes ofof SerialSerial Comm.Comm. z Most commonly available Tx Rx Rx Tx z Simple wiring CTS RTS z Low cost RTS CTS RS-232 z Short length (40 ft) DTR DSR DSR DTR Bar code reader z Slow data rates GND GND z Subject to noise Tx+ z High data rates Tx- z Longer cable lengths (4000 ft) Rx+ Rx- RS-422 z Full-duplex GND z Noise rejection PLC z Multipoint application (Up to 32 units) z Low cost Data+ z Longer cable lengths (4000 ft) Data- RS-485 zNoise immunity GND zHalf-duplex PLC SerialSerial V.S.V.S. ParallelParallel CommunicationCommunication Serial Communication Transfer the data bit by bit Synchronous Data Transfer Bit Send Data Receive Data Parallel Communication Transfer the all data simultaneously Asynchronous Data Transfer Bit Bit Bit Bit Bit Bit Bit Bit Send Data Receive Data SimplexSimplex ,, HalfHalf DuplexDuplex ,, FullFull DuplexDuplex CommunicationCommunication SimplexSimplex CommunicationCommunication Simplex Communication : – Data in a simplex channel is always one way. -
Signal Issue 37
Signal Issue 37 Tricks of the Trade Dave Porter G4OYX and Alan Beech G1BXG By 25th September 1965, Radio 390 was on the air and 31st December 2015 marks the fiftieth anniversary of the start of the offshore station Radio Scotland. The only remaining station to launch with RCA 10 kW Ampliphase transmitters was Radio 270 from 4th June 1966, on-air some three months later than originally planned. Member’s contribution understood that, whilst CE was used to these T-K arrangements, mainly for Government contracts, the need After reading the last three ToTT, VMARS Member Tony to effect a quick turn-around with minimal delays was not Rock G3KTR/AD1X contacted the author (DP) with the quite their norm. With time slipping by, the decision was following information on the 1965 build of Radio Scotland. made to leave the USA without the systems being totally commissioned and to complete en-route. Also, during this Tony writes; I read with interest the article you and Alan trip, it was discovered that one of the planned operating put together on Ampliphase transmitters. In the mid-1960s frequencies, namely 650 kHz, was actually occupied in the I was working out of the RCA Broadcast & UK by a certain high-power station on 647 kHz, the Communications Division at Sunbury-on-Thames. At this 150 kW BBC Third Programme. It was understood that an time RCA had sold several transmitters to offshore ‘pirate’ early ‘recce’ by the Americans to the UK to check for ‘spare radio stations. While Marconi and other European channels’ resulted in a monitoring time when the Third companies could be subjected to sanctions by the Programme was not scheduled on air. -
Radio Frequency Interference Analysis of Spectra from the Big Blade Antenna at the LWDA Site
Radio Frequency Interference Analysis of Spectra from the Big Blade Antenna at the LWDA Site Robert Duffin (GMU/NRL) and Paul S. Ray (NRL) March 23, 2007 Introduction The LWA analog receiver will be required to amplify and digitize RF signals over the full bandwidth of at least 20–80 MHz. This frequency range is populated with a number of strong sources of radio frequency interference (RFI), including several TV stations, HF broadcast transmissions, ham radio, and is adjacent to the FM band. Although filtering can be used to attenuate signals outside the band, the receiver must be designed with sufficient linearity and dynamic range to observe cosmic sources in the unoccupied regions between the, typically narrowband, RFI signals. A receiver of insufficient linearity will generate inter-modulation products at frequencies in the observing bands that will make it difficult or impossible to accomplish the science objectives. On the other hand, over-designing the receiver is undesirable because any excess cost or power usage will be multiplied by the 26,000 channels in the full design and may make the project unfeasible. Since the sky background is low level and broadband, the linearity requirements primarily depend on the RFI signals presented to the receiver. Consequently, a detailed study of the RFI environment at candidate LWA sites is essential. Often RFI surveys are done using antennas optimized for RFI detection such as discone antennas. However, such data are of limited usefulness for setting the receiver requirements because what is relevant is what signals are passed to the receiver when it is connected to the actual LWA antenna. -
Microwave Frequency Demodulation Using Two Coupled Optical Resonators with Modulated Refractive Index
PHYSICAL REVIEW APPLIED 15, 034056 (2021) Microwave Frequency Demodulation Using two Coupled Optical Resonators with Modulated Refractive Index Adam Mock * School of Engineering and Technology, Central Michigan University, Mount Pleasant, Michigan 48859, USA (Received 16 October 2020; revised 1 February 2021; accepted 10 February 2021; published 18 March 2021) Traditional electronic frequency demodulation of a microwave frequency voltage is challenging because it requires complicated phase-locked loops, narrowband filters with fixed passbands, or large footprint local oscillators and mixers. Herein, a different frequency demodulation concept is proposed based on refractive index modulation of two coupled microcavities excited by an optical wave. A frequency- modulated microwave frequency voltage is applied to two photonic crystal microcavities in a spatially odd configuration. The spatially odd perturbation causes coupling between the even and odd supermodes of the coupled-cavity system. It is shown theoretically and verified by finite-difference time-domain sim- ulations how careful choice of the modulation amplitude and frequency can switch the optical output from on to off. As the modulating frequency is detuned from its off value, the optical output switches from off to on. Ultimately, the optical output amplitude is proportional to the frequency deviation of the applied voltage making this device a frequency-modulated-voltage to amplitude-modulated-optical- wave converter. The optical output can be immediately detected and converted to a voltage that would result in a frequency-demodulated voltage signal. Or the optical output can be fed into a larger radio- over-fiber optical network. In this case the device presents a compact, low power, and tunable route for multiplexing frequency-modulated voltages with amplitude-modulated optical communication systems. -
Analysis and Study the Performance of Coaxial Cable Passed on Different Dielectrics
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 13, Number 3 (2018) pp. 1664-1669 © Research India Publications. http://www.ripublication.com Analysis and Study the Performance of Coaxial Cable Passed On Different Dielectrics Baydaa Hadi Saoudi Nursing Department, Technical Institute of Samawa, Iraq. Email:[email protected] Abstract Coaxial cable virtually keeps all the electromagnetic wave to the area inside it. Due to the mechanical properties, the In this research will discuss the more effective parameter is coaxial cable can be bent or twisted, also it can be strapped to the type of dielectric mediums (Polyimide, Polyethylene, and conductive supports without inducing unwanted currents in Teflon). the cable. The speed(S) of electromagnetic waves propagating This analysis of the performance related to dielectric mediums through a dielectric medium is given by: with respect to: Dielectric losses and its effect upon cable properties, dielectrics versus characteristic impedance, and the attenuation in the coaxial line for different dielectrics. The C: the velocity of light in a vacuum analysis depends on a simple mathematical model for coaxial cables to test the influence of the insulators (Dielectrics) µr: Magnetic relative permeability of dielectric medium performance. The simulation of this work is done using εr: Dielectric relative permittivity. Matlab/Simulink and presents the results according to the construction of the coaxial cable with its physical properties, The most common dielectric material is polyethylene, it has the types of losses in both the cable and the dielectric, and the good electrical properties, and it is cheap and flexible. role of dielectric in the propagation of electromagnetic waves. -
Wireless Power Transmission
International Journal of Scientific & Engineering Research, Volume 5, Issue 10, October-2014 125 ISSN 2229-5518 Wireless Power Transmission Mystica Augustine Michael Duke Final year student, Mechanical Engineering, CEG, Anna university, Chennai, Tamilnadu, India [email protected] ABSTRACT- The technology for wireless power transfer (WPT) is a varied and a complex process. The demand for electricity is much higher than the amount being produced. Generally, the power generated is transmitted through wires. To reduce transmission and distribution losses, researchers have drifted towards wireless energy transmission. The present paper discusses about the history, evolution, types, research and advantages of wireless power transmission. There are separate methods proposed for shorter and longer distance power transmission; Inductive coupling, Resonant inductive coupling and air ionization for short distances; Microwave and Laser transmission for longer distances. The pioneer of the field, Tesla attempted to create a powerful, wireless electric transmitter more than a century ago which has now seen an exponential growth. This paper as a whole illuminates all the efficient methods proposed for transmitting power without wires. —————————— —————————— INTRODUCTION Wireless power transfer involves the transmission of power from a power source to an electrical load without connectors, across an air gap. The basis of a wireless power system involves essentially two coils – a transmitter and receiver coil. The transmitter coil is energized by alternating current to generate a magnetic field, which in turn induces a current in the receiver coil (Ref 1). The basics of wireless power transfer involves the inductive transmission of energy from a transmitter to a receiver via an oscillating magnetic field. -
Additive Synthesis, Amplitude Modulation and Frequency Modulation
Additive Synthesis, Amplitude Modulation and Frequency Modulation Prof Eduardo R Miranda Varèse-Gastprofessor [email protected] Electronic Music Studio TU Berlin Institute of Communications Research http://www.kgw.tu-berlin.de/ Topics: Additive Synthesis Amplitude Modulation (and Ring Modulation) Frequency Modulation Additive Synthesis • The technique assumes that any periodic waveform can be modelled as a sum sinusoids at various amplitude envelopes and time-varying frequencies. • Works by summing up individually generated sinusoids in order to form a specific sound. Additive Synthesis eg21 Additive Synthesis eg24 • A very powerful and flexible technique. • But it is difficult to control manually and is computationally expensive. • Musical timbres: composed of dozens of time-varying partials. • It requires dozens of oscillators, noise generators and envelopes to obtain convincing simulations of acoustic sounds. • The specification and control of the parameter values for these components are difficult and time consuming. • Alternative approach: tools to obtain the synthesis parameters automatically from the analysis of the spectrum of sampled sounds. Amplitude Modulation • Modulation occurs when some aspect of an audio signal (carrier) varies according to the behaviour of another signal (modulator). • AM = when a modulator drives the amplitude of a carrier. • Simple AM: uses only 2 sinewave oscillators. eg23 • Complex AM: may involve more than 2 signals; or signals other than sinewaves may be employed as carriers and/or modulators. • Two types of AM: a) Classic AM b) Ring Modulation Classic AM • The output from the modulator is added to an offset amplitude value. • If there is no modulation, then the amplitude of the carrier will be equal to the offset. -
En 300 720 V2.1.0 (2015-12)
Draft ETSI EN 300 720 V2.1.0 (2015-12) HARMONISED EUROPEAN STANDARD Ultra-High Frequency (UHF) on-board vessels communications systems and equipment; Harmonised Standard covering the essential requirements of article 3.2 of the Directive 2014/53/EU 2 Draft ETSI EN 300 720 V2.1.0 (2015-12) Reference REN/ERM-TG26-136 Keywords Harmonised Standard, maritime, radio, UHF ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N° 348 623 562 00017 - NAF 742 C Association à but non lucratif enregistrée à la Sous-Préfecture de Grasse (06) N° 7803/88 Important notice The present document can be downloaded from: http://www.etsi.org/standards-search The present document may be made available in electronic versions and/or in print. The content of any electronic and/or print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any existing or perceived difference in contents between such versions and/or in print, the only prevailing document is the print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI Secretariat. Users of the present document should be aware that the document may be subject to revision or change of status. Information on the current status of this and other ETSI documents is available at http://portal.etsi.org/tb/status/status.asp If you find errors in the present document, please send your comment to one of the following services: https://portal.etsi.org/People/CommiteeSupportStaff.aspx Copyright Notification No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm except as authorized by written permission of ETSI. -
Implementation Considerations for the Introduction and Transition to Digital Terrestrial Sound and Multimedia Broadcasting
Report ITU-R BS.2384-0 (07/2015) Implementation considerations for the introduction and transition to digital terrestrial sound and multimedia broadcasting BS Series Broadcasting service (sound) ii Rep. ITU-R BS.2384-0 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. -
Transmission Line Characteristics
IOSR Journal of Electronics and Communication Engineering (IOSR-JECE) e-ISSN: 2278-2834, p- ISSN: 2278-8735. PP 67-77 www.iosrjournals.org Transmission Line Characteristics Nitha s.Unni1, Soumya A.M.2 1(Electronics and Communication Engineering, SNGE/ MGuniversity, India) 2(Electronics and Communication Engineering, SNGE/ MGuniversity, India) Abstract: A Transmission line is a device designed to guide electrical energy from one point to another. It is used, for example, to transfer the output rf energy of a transmitter to an antenna. This report provides detailed discussion on the transmission line characteristics. Math lab coding is used to plot the characteristics with respect to frequency and simulation is done using HFSS. Keywords - coupled line filters, micro strip transmission lines, personal area networks (pan), ultra wideband filter, uwb filters, ultra wide band communication systems. I. INTRODUCTION Transmission line is a device designed to guide electrical energy from one point to another. It is used, for example, to transfer the output rf energy of a transmitter to an antenna. This energy will not travel through normal electrical wire without great losses. Although the antenna can be connected directly to the transmitter, the antenna is usually located some distance away from the transmitter. On board ship, the transmitter is located inside a radio room and its associated antenna is mounted on a mast. A transmission line is used to connect the transmitter and the antenna The transmission line has a single purpose for both the transmitter and the antenna. This purpose is to transfer the energy output of the transmitter to the antenna with the least possible power loss. -
FM Stereo Format 1
A brief history • 1931 – Alan Blumlein, working for EMI in London patents the stereo recording technique, using a figure-eight miking arrangement. • 1933 – Armstrong demonstrates FM transmission to RCA • 1935 – Armstrong begins 50kW experimental FM station at Alpine, NJ • 1939 – GE inaugurates FM broadcasting in Schenectady, NY – TV demonstrations held at World’s Fair in New York and Golden Gate Interna- tional Exhibition in San Francisco – Roosevelt becomes first U.S. president to give a speech on television – DuMont company begins producing television sets for consumers • 1942 – Digital computer conceived • 1945 – FM broadcast band moved to 88-108MHz • 1947 – First taped US radio network program airs, featuring Bing Crosby – 3M introduces Scotch 100 audio tape – Transistor effect demonstrated at Bell Labs • 1950 – Stereo tape recorder, Magnecord 1250, introduced • 1953 – Wireless microphone demonstrated – AM transmitter remote control authorized by FCC – 405-line color system developed by CBS with ”crispening circuits” to improve apparent picture resolution 1 – FCC reverses its decision to approve the CBS color system, deciding instead to authorize use of the color-compatible system developed by NTSC – Color TV broadcasting begins • 1955 – Computer hard disk introduced • 1957 – Laser developed • 1959 – National Stereophonic Radio Committee formed to decide on an FM stereo system • 1960 – Stereo FM tests conducted over KDKA-FM Pittsburgh • 1961 – Great Rose Bowl Hoax University of Washington vs. Minnesota (17-7) – Chevrolet Impala ‘Super Sport’ Convertible with 409 cubic inch V8 built – FM stereo transmission system approved by FCC – First live televised presidential news conference (John Kennedy) • 1962 – Philips introduces audio cassette tape player – The Beatles release their first UK single Love Me Do/P.S.