Measurement Of Evm Error Vector Magnitude For 3g Receivers
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Download Links [db.s2.chalmers.se] Save to List Add to Collection Correct Errors Monitor Changes by Emw/tb/rbc Ödgärd Andersson February A , Osvaldo Mendoza , Supervisors Zalina Adnan , Examiner Arne Svensson , Mendoza Emw/tb/rb-: Uen , Mendoza Emw/tb/rb-: Uen , earned value management definition Zalina Adnan , Vimar Björk , Vimar Björk , Arne Svensson Summary Citations Active
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author = {Emw/tb/rbc Ödgärd Andersson February A and Osvaldo Mendoza and Supervisors Zalina Adnan and error vector magnitude calculation Examiner Arne Svensson and Mendoza Emw/tb/rb-: Uen and Mendoza Emw/tb/rb-: Uen and Zalina Adnan and Vimar Björk and Vimar Björk and Arne Svensson},title = {Measurement of EVM (Error Vector Magnitude) for 3G Receivers},year = {2002}} error vector magnitude pdf Share OpenURL Abstract The aim of this thesis work is to measure the Error Vector Magnitude (EVM) directly at the radio receiver of the 3 rd Generation WCDMA base stations, specifically at the gamma bus, and the output of the analogue to digital converters. The EVM is a figure-of-merit for the down-conversion of the modulated radio signal and is a measure of the signal to noise and distortion ratio. The
Evm Vs Snr
error vector is obtained by subtracting the received signal from an ideal reference signal. The set-up consists of generating an RF signal using a signal generator, feeding it into the receiver, and acquiring it from the interfaces of interest using a logic analyzer. The ideal reference signal is created by means of software. The work done in this project includes an algorithm proposal to measure the received signal at the optimal position, this algorithm is based on the eye diagram, specifically, in the analysis of the variance of the signal's magnitude. In addition, another algorithm was developed to compensate for the effects of frequency offsets introduced by the RF local oscillator. The frequency offsets can be visualized as phase variations of the IQ constellation in the time domain, such phase variations were tracked and compensated using a one-tap Least Mean-Square adaptive filter. Both algorithms were implemented in software using Labview, resulting in an EVMRMS of 6.6% at the gamma bus, and 4.5% at the ADCs. The signal measured at the gamma bus was affected by quantization noise, therefore, it was low-pass filtered to minimize the problem. Open REPORT 4 (78) Prepared (also subject responsible if other) No. Keyphrases error vector magnitude gamma bus ideal reference signal received signal frequency offset phase
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Evm Vs Ber
Energy Lighting Medical Mobile Robotics Learning ResourcesEngineering Essentials Design Solutions What’s The Difference Between… Ideas for Design Salary Survey Salary Calculator White Papers http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.16.1325 Basics of Design eBooks Webcasts 2016 Leaders in Electronics Design FAQs Data Sheets Reference Designs 11 Myths About... Electronic Design Library CommunityBlogs Bob Pease Contributing Technical Experts Engineering Hall of Fame Interviews Our Editors STEM Starter Tournament Pop Quizzes Engineering Bracket Challenge CompaniesCompany Directory Part Search Advertisement Home http://electronicdesign.com/engineering-essentials/understanding-error-vector-magnitude > Learning Resources > Engineering Essentials > Understanding Error Vector Magnitude Understanding Error Vector Magnitude This measure of modulation quality may be a better predictor of wireless reliability than BER. Oct 10, 2013 Lou Frenzel | Electronic Design EMAIL Tweet Comments 0 Learn the meaning and importance of error vector magnitude measurements. Download this article in .PDF format This file type includes high resolution graphics and schematics when applicable. Error vector magnitude (EVM) is a measure of modulation quality and error performance in complex wireless systems. It provides a method to evaluate the performance of software-defined radios (SDRs), both transmitters and receivers. It also is widely used as an alternative to bit error rate (BER) measurements to determine impairments that affect signal reliability. (BER is the percentage of bit errors that occur for a given number of bits transmitted.) E
noise, interfering signals, nonlinear distortion and the load of the radio. It is a component of the 802.11 IEEE standard, and has become an industry standard measurement for cellular phones, cable television and wifi. EVM is typically measured in decibels (dB), http://www.antenna-theory.com/definitions/evm.php and sometimes in percent. An example will make this is clear, assuming you know a http://ieeexplore.ieee.org/abstract/document/4927484/ bit about digital modulation techniques (QAM, QPSK, PSK, etc). Suppose our radio is transmitting via a 16-QAM constellation. It would like to send the black dots below in the I-Q (In phase - Quadrature Plane) plane. However, due to our real-world (non-ideal) radio, suppose the radio actually transmits something a bit off of this point: Figure 1. Illustration of A 16-QAM Constellation. In error vector Figure 1, we have a 16-QAM constellation, which means we encode our 1's and 0's as 16 different symbols, with 4 bits per symbol. At this instant in Figure 1, suppose we are transmitting the symbol pointed to by the orange vector, or bits [0000]. In this case, we are transmitting exactly what our radio wants to transmit; simiarly this is what the receiver would expect to receive with no noise present. Now, suppose that our radio is error vector magnitude not perfect for whatever reason. Then we won't be exactly transmitting the symbol we want to send. The difference between the desired (ideal) signal vector and the actual signal vector is the error vector, as shown in Figure 2. And the magnitude of the error vector? This is EVM. Figure 2. Illustration of The Error Vector Magnitude (EVM). Now, if you have noise in your system, this disturbs your measurements as well. However, EVM is not noise. Noise arises from some external source and can be reduced via averaging or other techniques. We'll return to what causes EVM in a minute. EVM is typically measured in dB, as in: EVM=-28 dB. This means the error vector has a magnitude that is 28 dB less than the average signal vector (or, the average energy per symbol we transmit). Hence, we can write EVM mathematically as: EVM is typically less than -20 dB, and often much lower depending on the application. How does EVM relate to Antennas? As this website doesn't focus too much on radios, you may be wondering why the topic of EVM is being studied in an antenna theory website. Well it turns out that the antenna can significantly affect EVM. How? The antenna's impedance presents itself as a load to the radio. If the antenna has a poor impedance match, then it will have a high VSWR. This presents a
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