337 research outputs found

    A 12 GHz satellite video receiver: Low noise, low cost prototype model for TV reception from broadcast satellites

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    A 12-channel synchronous phase lock video receiver consisting of an outdoor downconverter unit and an indoor demodulator unit was developed to provide both low noise performance and low cost in production quantities of 1000 units. The prototype receiver can be mass produced at a cost under $1540 without sacrificing system performance. The receiver also has the capability of selecting any of the twelve assigned satellite broadcast channels in the frequency range 11.7 to 12.2 GHz

    UMTV: a Single Chip TV Receiver for PDAs, PCs and Cell Phones

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    A zero-external-component TV receiver for portable platforms is realized in a mainstream 8GHz-f/sub t/ BiCMOS process. Die size is 5/spl times/5mm/sup 2/ and power dissipation is 50mA at 3V. The receiver includes a single tunable LNA (3mA) with less than 5dB NF from 40 to 900MHz. The programmable IF filters cover all analog and digital standards

    Replacing the automatic gain control loop in a mobile, digital TV broadcast receiver by a software based solution

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    The power level (the amplitude) of an electro-magnetic signal wave suffers from attenuation the greater the distance between the transmitter and the receiver is. The receiver of that signal therefore has components which try to amplify the signal so that it can be processed optimally by a processor. In a mobile or portable environment the signal power level can vary strongly, because the position of the receiver to the transmitter is not fixed. In order to compensate that movement a control loop exists, which dynamically is adapting the front-end to the right level. This work describes a new, software-based way to handle the signal level control loop (formerly automatic gain control) in a digital TV receiver. Starting with a very basic introduction into digital communications, including the description of the traditional front-end architecture, followed by a detailed description of the new method. Finally some conclusions of this new method are made which are giving an idea about how in the future it might be possible to reach better receiving performances using this mechanism

    The LHC Low Level RF

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    The LHC RF consists of eight 400 MHz superconducting cavities per ring, with each cavity independently powered by a 300 kW klystron, via a circulator. The challenge for the Low Level is to cope with very high beam current (more than 1 A RF component) and achieve excellent beam lifetime (emittance growth time in excess of 25 hours). Each cavity has an associated Cavity Controller rack consisting of two VME crates which implement high gain RF Feedback, a Tuner Loop with a new algorithm, a Klystron Ripple Loop and a Conditioning system. In addition each ring has a Beam Control system (four VME crates) which includes a Frequency Program, Phase Loop, Radial Loop and Synchronization Loop. A Longitudinal Damper (dipole and quadrupole mode) acting via the 400 MHz cavities is included to reduce emittance blow-up due to filamentation from phase and energy errors at injection. Finally an RF Synchronization system implements the bunch into bucket transfer from the SPS into each LHC ring. When fully installed in 2007, the whole system will count over three hundred home-designed VME cards of twenty-three different models installed in forty-five VME crates. The paper presents the various loops: it outlines the expected performances, summarizes the algorithms and the implementation. Thanks to a full scale test set-up including klystron and cavity we have measured the response of the RF Feedback and Tuner Loop; and these will be presented and compared to the expectations

    Wireless recording of the calls of Rousettus aegyptiacus and their reproduction using electrostatic transducers

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    Bats are capable of imaging their surroundings in great detail using echolocation. To apply similar methods to human engineering systems requires the capability to measure and recreate the signals used, and to understand the processing applied to returning echoes. In this work, the emitted and reflected echolocation signals of Rousettus aegyptiacus are recorded while the bat is in flight, using a wireless sensor mounted on the bat. The sensor is designed to replicate the acoustic gain control which bats are known to use, applying a gain to returning echoes that is dependent on the incurred time delay. Employing this technique allows emitted and reflected echolocation calls, which have a wide dynamic range, to be recorded. The recorded echoes demonstrate the complexity of environment reconstruction using echolocation. The sensor is also used to make accurate recordings of the emitted calls, and these calls are recreated in the laboratory using custom-built wideband electrostatic transducers, allied with a spectral equalization technique. This technique is further demonstrated by recreating multi-harmonic bioinspired FM chirps. The ability to record and accurately synthesize echolocation calls enables the exploitation of biological signals in human engineering systems for sonar, materials characterization and imaging

    Receptor Web-SDR a l'EETAC

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    In this project has designed, installed and configured a system of reception of signals of RF using SDR (Software Defined Radio) low cost receivers that by means of a web interface allow to decode the signals to any user of the world, via internet, without the need to have a receptor of radio, this system works to the amateur radio operator (ham) bands and is multiuser. This online receptor contrived for the use in the ham bands but can be also be used in any one other band in function of his configuration, this project is another service that provides the school of telecommunications in order to give visibility around of the world especially between the hams than are the main users of the webSDR systems. The modulations that bears this system sleep: ◦ AM, FM, LSB, USB, CW To receive the signals have used two receptors SDR (Funcube Dongle Pro +, RTL-SDR)to the bands of 144MHz(2m) VHF and 7MHz (40m) HF and have built two antennas for the two bands. The antenna of VHF (2m) a ground plane and the second antenna for the band of HF (40m) has been a double bazooka antenna. All the system will be supported by a PC, with a Intel Pentium D CPU at 3GHz and 2GB of RAM memory, that we will use as a server. This incorporates all the necessary software loaded in the operating system Ubuntu 14.04LTS lodged under the IP 147.83.115.237 and with two open ports (8072 and 8073) designated to provide access to the information acquired by the different dongles. As added value for this project a BPSK31 signal decoder was designed on Scilab, this functionality is not present on any webSDR program yet

    DCS: A global satellite environmental data collection system study

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    Cost analysis and technical feasibility data are presented on five medium orbiting and six geosynchronous satellite data collection systems with varying degrees of spacecraft and local user terminal complexity. Data are also provided on system approaches, user requirements, and user classes. Systems considered include orbiting ERTS and EOS type satellites and geosynchronous SmS and SEOS type data collectors

    An Effective Satellite Remote Sensing Tool Combining Hardware and Software Solutions

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    In this paper we propose a new effective remote sensing tool combining hardware and software solutions as an extension of our previous work. In greater detail the tool consists of a low cost receiver subsystem for public weather satellites and a signal and image processing module for several tasks such as signal and image enhancement, image reconstruction and cloud detection. Our solution allows to manage data from satellites effectively with low cost components and portable software solutions. We aim at sampling and processing of the modulated signal entirely in software enabled by Software Defined Radios (SDR) and CPU computational speed overcoming hardware limitation such as high receiver noise and low ADC resolution. Since we want to extend our previous method to demodulate signals coming from various meteorological satellites, we propose a new high frequency receiving system designed to receive and demodulate signals transmitted at 1.7 GHz. The signals coming from satellites are demodulated, synchronized and enhanced by using low level image processing techniques, then cloud detection is performed by using the well known K-means clustering algorithm. The hardware and software architecture extensions make our solution able to receive and demodulate high frequency and bandwidth meteorological satellite signals, such as those transmitted by NOAA POES, NOAA GOES, EUMETSAT Metop, Meteor-M and FengYun

    Software defined radio (SDR) on radiocommunications teaching

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    The recent outbreak of Software Defined Radios (SDR), where traditionally hardware components are substituted by software, have revolutionized the way we understand and manage radiocommunications. The current state of technology allows low cost SDR receivers to tune emissions in a simple way with almost no experience and little effort. The great flexibility of this equipment allows a perfect adaptation of the practice part of the subject to the theory objectives and makes possible to learn outside the classroom, something unthinkable until now. To achieve this, the student only needs a low-cost SDR receiver, a computer and some free software. This paper presents a new teaching methodology for practicing radiocommunications subject using a workstation based on a SDR device that can receive, display and analyze radio transmissions. Subject learning outcomes and skills are acquired and strengthened through experimentation with this new kind of devices. This platform also represents a significant saving because avoids our university to buy expensive and closed "training kits".CUD Universidad de Vigo Grupo de Investigación Señales, Sistemas y Comunicaciones Navales. Universidad de Cádi
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