Error Magnitude Vector
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Error Vector Mag
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Error Vector Magnitude Calculation
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.) EVM provides an improved picture of the modulation quality as well. Related 3G Transceiver Consumes 30% Less Power And Delivers 50% Better EVM VSA App Adds Multi-Measurement Signal Analyzer Capability Understanding Cell-Aware ATPG And User-Defined Fault Models A Multi-Level Approach Makes Understanding Motor Control Easier EVM measurements are normally used with multi-symbol modulation methods like multi-level phase-shift keying (M-PSK), quadrature phase-shift keying (QPSK), and multi-level q
Федерация 中国 (China) 日本 (Japan) 대한민국 (Korea) 台灣 (Taiwan) See All Countries Toggle navigation INNOVATIONEN PRODUKTE SUPPORT COMMUNITY Deutschland Modulation Error error vector magnitude qam Ratio (MER) and Error Vector Magnitude (EVM) Publish Date: Nov 04, error vector magnitude matlab 2014 | 25 Bewertung(en) | 2,68 von 5 | Print Overview This tutorial is part of
Error Vector Magnitude Analysis
the National Instruments Measurement Fundamentals series. Each tutorial in this series teaches you a specific topic of common measurement applications by explaining the theory and http://electronicdesign.com/engineering-essentials/understanding-error-vector-magnitude giving practical examples. This tutorial covers an introduction to RF, wireless, and high-frequency signals and systems. For the complete list of tutorials, return to the NI Measurement Fundamentals Main page, or for more RF tutorials, refer to the NI RF Fundamentals main subpage. For more information about National Instruments RF products, http://www.ni.com/white-paper/3652/en/ visit www.ni.com/rf. Table of Contents Modulation Error Ratio (MER) Error Vector Magnitude (EVM) Related Products Conclusion 1. Modulation Error Ratio (MER) The modulation error ratio (MER) is a measure of the signal-to-noise ratio (SNR) in a digitally modulated signal. Like SNR, MER is usually expressed in decibels (dB). MER over number of symbols, N is defined as: where is the I component of the j-th symbol received is the Q component of the j-th symbol received is the ideal I component of the j-th symbol received and is the ideal Q component of the j-th symbol received. Back to Top 2. Error Vector Magnitude (EVM) Error vector magnitude(EVM) is a measurement of demodulator performance in the presence of impairments. The measured symbol location obtained after decimating the recovered waveform at the demodulator output are compared against the ideal symbol locations. The root-mean-square (RMS) EVM and phase error are then used
detected symbol location—which connects the I/Q reference-signal vector to the I/Q measured-signal vector. The following graphic shows the calculation of the EVM metric as well as a diagram showing how a single error http://rfmw.em.keysight.com/wireless/helpfiles/89600B/WebHelp/Subsystems/digdemod/content/digdemod_symtblerrdata_evm.htm vector is calculated. EVM is calculated from the symbol points (the instant in time when symbols are detected). The computation does not include points between symbols. Therefore Points / Symbol does not affect the value. The Syms/Errs table also shows the location of the symbol that has the largest EVMError vector magnitude (EVM): A quality metric in digital communication systems. See the EVM metric in the Error Summary Table topic error vector in each demodulator for more information on how EVM is calculated for that modulation format.. For constellations with constant magnitude (QPSKQuadrature phase shift keying, BPSKBinary phase shift keying - A type of phase modulation using 2 distinct carrier phases to signal ones and zeros., 8PSK, etc.), the EVMs are always normalized to the constellation maximum. For constellations with multiple possible magnitudes (APSK, StarQAM, 16QAM, 32QAM, etc.), the EVMs are normalized to error vector mag the EVM Normalization Reference. Shaped OQPSKOffset Quadrature Phase Shift Keying: A type of QPSK modulation that offsets the bit streams on the I and Q channels by a half bit. This reduces amplitude fluctuations and helps improve spectral efficiency. and Offset QPSK use two points-per-symbol (symbols and midpoints between symbols) to compute EVM and peak EVM due to the offset between IandQ. For Offset QPSK, when the Half Sine Filter is selected, the OQPSK reference constellation points fall on a circle with a magnitude of sqrt(2)/2, but the EVM is still expressed as a percentage of the magnitude of a QPSK symbol point (magnitude = 1). For the EDGEEnhanced Data for Global Evolution: A technology that gives GSMA and TDMA similar capacity to handle services for the third generation of mobile telephony. EDGE was developed to enable the transmission of large amounts of data at a high speed, 384 kilobits per second. (It increases available time slots and data rates over existing wireless networks.) demodulation format, the EVM, Phase, and Magnitude Error data results may vary for different Points / Symbol settings. When Points / Symbol is set to 1 (default), the trace data results are compensated for ISIInter-Symbol Interference: An interference effect where energy from prior symbols in a bit