AT4 Wireless

Málaga, Spain

AT4 Wireless

Málaga, Spain
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Oya J.R.G.,University of Seville | Munoz F.,University of Seville | Torralba A.,University of Seville | Jurado A.,AT4 Wireless | And 2 more authors.
IEEE Transactions on Instrumentation and Measurement | Year: 2011

In this paper, a data acquisition module meeting the specifications of a wideband multistandard receiver test system is presented. It provides a high resolution over large bandwidth with only a low-jitter wideband sample-and-hold and an intermediate frequency analog-to-digital converter by means of subsampling. Using commercial devices on a multilayer printed circuit board, experimental results showed more than a resolution of 8 b for a signal bandwidth of 20 MHz with a center frequency of up to 4GHz, which is enough to cover the requirements of test systems for most of present wireless communication standards. © 2011 IEEE.


Oya J.R.G.,University of Seville | Munoz F.,University of Seville | Torralba A.,University of Seville | Jurado A.,AT4 Wireless | And 2 more authors.
IEEE Transactions on Instrumentation and Measurement | Year: 2012

This paper presents the implementation of a data acquisition system, where the folded thermal noise is reduced by using two consecutive subsampling processes. The presented implementation is used to test wideband multistandard receivers covering most of present communication standards. The proposed system converts a 20-MHz signal modulated with a programmable carrier frequency up to 6.5 GHz, so that it could be used as a universal receiver for software-defined radio applications. Experimental results show an effective number of bits larger than 9 bits up to 2.9 GHz, 8 bits up to 6.5 GHz, and 6.4 bits up to 20 GHz of input carrier frequency. © 1963-2012 IEEE.


Perez-Lara P.,AT4 Wireless | Molina-Fernandez I.,University of Malaga | Wanguemert-Perez J.G.,University of Malaga | Rueda-Perez A.,University of Malaga
IEEE Transactions on Microwave Theory and Techniques | Year: 2010

A simple five-port direct receiver achieving broadband performance and high local oscillator to RF isolation is presented. The new circuit comprises three power detectors exhibiting high series impedance, four resistors, and two low-pass and two high-pass phase shifters. It is shown that the phase-shift networks can be designed to optimize receiver operation over a theoretical decade bandwidth. A 300-MHz2.7-GHz prototype is built and measured to prove feasibility of this proposal. © 2006 IEEE.


Lopez-Berrocal B.,AT4 Wireless | De-Oliva-Rubio J.,University of Malaga | Molina-Fernandez I.,University of Malaga | Montejo-Garai J.R.,University of Malaga
International Journal of RF and Microwave Computer-Aided Engineering | Year: 2014

This article presents a simple topology for the implementation of cross-couplings between nonadjacent resonators in interdigital stripline filters. This topology affords the inclusion of transmission zeros maintaining a cross-sectional structure similar to that of a stripline. Therefore, the manufacturing cost is very close to an all-pole prototype. Two design strategies for the coupling structure are discussed: one of them achieving filters with enhanced performance. Both strategies have been assessed implementing prototypes in low-temperature cofired ceramic (LTCC) technology. The fabricated filters exhibit operating frequencies at 5775 MHz and 8000 MHz with 2.6% and 3.75% pass-band fractional bandwidths, respectively, and up to 60 dB IL in the rejection band. © 2014 Wiley Periodicals, Inc.


Rivas F.J.,AT4 Wireless | Diaz Zayas A.,University of Malaga | Merino Gomez P.,University of Malaga
Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering | Year: 2012

This paper introduces an experimental testbed developed at the University of Malaga to analyze the behavior of mobile applications and services over LTE (Long Term Evolution) networks. The novelty of the testbed is the ability to correlate the impact of radio propagation issues on LTE configurations and applications protocols and cross tuning LTE parameters and IP protocols from the point of view of the quality perceived by end users. In this work we focus on the evaluation of VoIP services over LTE networks. © 2012 ICST Institute for Computer Science, Social Informatics and Telecommunications Engineering.


Diaz Zayas A.,University of Malaga | Rivas F.J.,AT4 Wireless | Merino Gomez P.,University of Malaga
Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering | Year: 2012

UMA (University of Malaga) is developing a testing facility to provide support for the complete development process of Internet services in mobile networks. The platform enables the execution of data services on instrumented mobiles and will offer a remote access to carry out unattended measurement campaigns in commercial and emulated cellular networks. The facility mainly targets data connectivity and performance over cellular networks (GSM, GPRS, UMTS, HSPA and LTE), mobility procedure analysis, IP traffic monitoring, energy consumption and location. © 2012 ICST Institute for Computer Science, Social Informatics and Telecommunications Engineering.


Witrisal K.,University of Graz | Pausini M.,AT4 Wireless
Proceedings of the 5th European Conference on Antennas and Propagation, EUCAP 2011 | Year: 2011

A statistical characterization is presented of the impact of the ultra-wideband (UWB) multipath channel on impulse radio and spread-spectrum UWB systems. For this purpose, the correlator output statistics are studied, since correlators are the typical first processing step in the frontends of coherent and noncoherent receivers. The analysis is based on the second and forth-order moments of the channel impulse response. It also includes a prototype pulse shape that represents the bandwidth of the received pulse and all linear system components including antenna effects. Complex-equivalent baseband representations of UWB pulses are assumed, which makes the analysis suitable for investigating bandpass-type UWB systems as defined in various IEEE standards. The analytical results are validated through the analysis of measured UWB channels. © 2011 EurAAP.


News Article | February 15, 2017
Site: www.prweb.com

Multi-Tech Systems, Inc., a leading global provider of M2M and IoT devices, today announced its MultiConnect® mDot™ a LoRaWAN™ 915 MHz ready, smart LPWAN RF module, is now fully certified by the LoRa AllianceTM through its LoRaWAN North American 915 MHz certification process conducted at AT4 Wireless laboratory in Malaga, Spain. This latest certification makes the MultiConnect mDot the first product to formally comply with the LoRaWAN specifications for North America. The MultiConnect mDot achieved LoRa Alliance certification for operation on European 868 MHz ISM-band in 2016. MultiConnect mDots use the new Semtech LoRa®, low power, wide area RF modulation to extend range and minimize the number of gateways required with no mesh. MultiConnect mDots reduce complexity and cost and enable intelligence at the very edge of the network by running ARM's mbed™ OS 5.3 on a low power ARM® Cortex®-M4 series processor. Customers integrating the mDot into their final design can now leverage the solutions broad set of certifications, including CE, FCC and LoRaWAN. Reusing these regulatory and industry approvals allows design engineers to avoid complex radio testing, significantly de-risking costly delays associated with achieving global approvals for their end device. “We’re pleased to be first with LoRaWAN certification for the North American market,” said Daniel Quant, Vice President of Product Management and Strategic Marketing MultiTech. “Achieving this industry first means our customers can deploy LoRa networks across North America and Europe with fully certified devices.” More information on LoRaWAN and how it is becoming the ubiquitous standard for secure, carrier-grade Low Power Wide Area Networks can be obtained at the LoRa Alliance Members Meeting and Open House taking place on January 23-25, 2017 at the Royal Garden Hotel in London. LoRa is a wireless technology developed to enable low data rate communications over long distances utilizing sensors and actuators for M2M and IoT applications. It is particularly attractive for many applications because of its long-range capability, ability to enable battery operated assets to function for years, and its low cost/high ROI benefits. LoRa’s advantages consist of its excellent range, low power consumption, good data security, and good ability to penetrate obstacles. In addition, it is completely bidirectional, enabling remote control applications. MultiTech designs, develops and manufactures communications equipment for the industrial internet of things – connecting physical assets to business processes to deliver enhanced value. Our commitment to quality and service excellence means you can count on MultiTech products and people to address your needs, while our history of innovation ensures you can stay ahead of the latest technology with a partner who will be there for the life of your solution. For more information, please visit http://www.multitech.com.


Flores J.L.,AT4 Wireless
Microwave Journal | Year: 2010

A new method for mixer spurs calculation, which has been found easier and more straightforward to use than the traditional spurs chart approach when dealing with the frequency plan optimization in broadband double conversion transceivers suitable for applications as multiband, multi standard and Software Defined Radio (SDR) is discussed. Regardless of the output spectrum component levels in a particular frequency conversion, their frequency values can be obtained in a much more generic way. The maximum pass band for the RF filter will be determined by its guard value selected and the IMP allowed in the IF band. The Distances Chart is a new method to find mixer spurs, allowing for an easy optimization of the IF and RF filter bands as well as the LO sweep band in applications where a broad frequency band with wide IF is to be covered, as in the case of broadband double conversion transceivers for multiband, multi standard and SDR applications. This method is easier and more straightforward to use than the traditional spurs chart approach during the study phase of such converters.


Trademark
At4 Wireless | Date: 2015-04-30

Computer software for testing and measuring telephone networks, wireless networks and telecommunication apparatus; computer software for testing and measuring electric apparatus and electronic apparatus; computer software platforms for testing and measuring telephone networks, wireless networks and telecommunication apparatus; computer software platforms for testing and measuring electric apparatus and electronic apparatus; computer software for testing and measuring mobile telephony operator systems; interfaces and peripheral devices for computers; computer hardware for use in computer-assisted software engineering; software; computer software platforms for testing and measuring telephone networks, wireless networks, electric apparatus, electronic apparatus and telecommunication apparatus. Database management; systematization of computer databases; compilation of information into databases; commercial business management.

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