Modulation error rate

The modulation error rate , English modulation error rate , abbreviated MER is in communication engineering a measure of the quality of digital modulation methods . It is mainly used in the field of digital television technology (DVB).

Digital modulation errors can be expressed graphically in the complex level of a constellation diagram through deviations from the ideal constellation points , which are caused by disturbances such as noise . These constellation points represent the symbols used in the context of digital modulation . Formally, the modulation error rate can be expressed as the relation between the effective value of the interference signals at the time-discrete sampling times and the effective value of the modulated signal using a sequence of symbols as: ${\displaystyle U_{\mathrm {err} }}$ ${\displaystyle U_{\mathrm {RMS} }}$ ${\displaystyle N}$

${\displaystyle MER_{\mathrm {RMS} }={\frac {\sqrt {{\frac {1}{N}}\sum _{n=0}^{N-1}U_{\mathrm {err} }^{2}}}{U_{\mathrm {RMS} }}}}$

Usually the MER is expressed as a logarithmic measure in decibels as:

${\displaystyle MER_{\mathrm {dB} }=20\cdot \log \left(MER_{\mathrm {RMS} }\right)}$

The modulation error rate is basically smaller than the signal-to-noise ratio .

literature

• Walter Fischer: Digital television technology in theory and practice. MPEG basic coding, DVB, DAB, ATSC transmission technology, measurement technology . Springer, 2006, ISBN 978-3-540-29203-6 , Chapter 18.2.5: Modulation Error Rate (MER).
• Andres Keller: Broadband cables and access networks. Technical principles and standards. Springer-Verlag, Berlin / Heidelberg 2011, ISBN 978-3-642-17631-9 .
• Walter Fischer: Digital television and radio technology in theory and practice. MPEG baseband coding, DVB, DAB, ATSC, ISDB-T transmission technology, measurement technology . 2nd edition, Springer Verlag, Berlin / Heidelberg 2009, ISBN 978-3-540-88187-2 .

Individual evidence

1. ↑ ETR 290: Measurement guidelines for DVB systems. European Telecommunications Standards Institute (ETSI), 1997, accessed November 15, 2016 . 

Web links

• DVB Lexicon (accessed September 14, 2017)
• Measurements in digital transmission systems using the example of DVB-T (accessed on September 14, 2017)
• Noise measurements on DVB signals (accessed on September 14, 2017)