BER MER OR BIT ERROR RATE MODULATION ERROR RATIO, BER MER OR BIT ERROR RATE MODULATION ERROR RATIO, BER MER OR BIT ERROR RATE MODULATION ERROR RATIO, Equalized or unequalized modulation error ratio (MER), that is. The answer is, “it depends.”. Let’s back up a bit and look at the concept of equalization from the perspective of a coaxial cable distribution network. As you know, in a given length of cable, higher frequencies are.
Un -equalized MER is typically measured before the adaptive equalizer and equalized MER is measured after the adaptive equalizer but often this circuitry resides in the QAM demodulator and cannot be disabled. So while the adaptive equalizer performs a great job of improving MER of a QAM signal, it does makes troubleshooting, 5/1/2012 · The type of measurement – equalized or unequalized – must be stated when defining MER performance metrics. It’s normal for unequalized MER to be a few dB lower than an equalized MER measurement on a given signal, but I have seen 10 dB or more difference when significant in-channel linear distortions were present.
9/6/2017 · MER is measured in dB. We need to keep MER 3 to 6 dB above from the unequalized MER value for proper receiving of signal. The unequalized MER value is different for different modulation i.e. QPSK ? 18 dB. 16 QAM ? 24 dB. 64 QAM ? 27 dB. 256 QAM ? 31 dB. Try to maintain high MER for proper signal receiving. Reasons For Degradation Of MER, MER = 10log 10 (average symbol power/average error power) I In effect, MER is a measure of how fuzzy the symbol points in a constellation are. Lab and field test results: Limitations of real-world MER measurements• Different makes/models of test equipment report different equalized and unequalized MER values on the same signal under identical conditions.
Good engineering practice says to keep unequalized MER 3 to 6 dB above the unequalized MER “failure threshold” for the modulation type in use Many cable operators use the following unequalized MER values as minimum acceptable operational values: QPSK ~18 dB 16-QAM ~24 dB 64-QAM ~27 dB and 256-QAM ~31 dB. So in general terms MER is, in effect, a measure of the “fuzziness” of a data, This means that for the same signal under identical conditions, unequalized MER will always be at least a few decibels less than an equalized value. How do you calculate bit error rate? The BER is calculated by comparing the transmitted sequence of bits to.
Equalized and Unequalized MER – Unequalized MER is typically measured before the adaptive equalizer and equalized MER is measured after the adapter equalizer, but often this circuitry resides in the QAM receiver and cannot be disabled. So while the adaptive equalizer does a great job improving MER of a QAM signal, it is also important, using the MAC address. The downward spikes in the MER strip chart in Figure 25 indicated bad packets, the pink line is equalized MER, and the brown line is unequalized MER. Figure 25. MER chart for a specific MAC address As Figure 26 shows, the first modem in the radio frequency (RF) path was verified from the subscriber’s
