User Manual DDS200 Digital Demodulation System 070-9952-00

Manual OperationFigure 2–34: ALARM: STATISTICS menuThe displayed times are the sums of times during which an alarm was active overthe monitoring time. In the case of a data error (DE), the number of events (to bemore exact, the duration of the error in seconds) is summed up.Statistical values are calculated in addition and indicated as an error in %. Thepercentage values are always referenced to the elapsed monitoring time. A 0.13%for MPEG DATA ERROR TIME would mean that faulty MPEG data werereceived for 0.13% of the seconds of the monitoring period. At this point, itcannot be distinguished whether the error lasted for one second or whether itoccurred several times within this period.Detailed error information can be obtained from the MPEG DATA ERROR CNTand MPEG DATA CORR CNT counters, which indicate the absolute number offaulty MPEG frames detected (MPEG DATA ERROR CNT, 1 frame comprises188 information-bearing bytes) or the absolute number of corrected bytes (MPEGDATA CORR CNT). When the alarm register is cleared, both counters are resetto 0. The counting limit is 4 294 836 225. When this number is reached, thecounter stops. In the worst case, an overflow of the ERROR counter occurs after5.88 hours of continuous errors at a symbol rate of 6.9 MSPS with 64QAMmodulation. In practice, the number of faulty MPEG frames is below 1%, whichmakes the measurement time of the ERROR counter to be more than threeweeks.2–42 DDS200 Digital Demodulation System User Manual