User Manual DDS200 Digital Demodulation System 070-9952-00

Manual OperationTable 2–2 provides more detailed information about the messages.Table 2–2: Messages displayed in the MEASURE menuMessage Meaning Possible sourcesBER EXTERNExternal BER measurement mode selected(SPECIAL FUNCTION menu).ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁSYMBOL RATE UNSYNCSymbol rate recovery not synchronized.The set symbol rate is not correct (STATUSmenu).ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁCARRIER RECOVERY UNSYNCFRAME UNSYNCCarrier recovery not synchronized.No MPEG sync word found.The set frequency is not correct or the jitterin the signal too high.The signal to be measured does notinclude an MPEG transport stream. This isthe case if the BER is too high. See alsoI/Q INVERSION on page 2–36.ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁEXT BER measurement mode selected(SPECIAL FUNCTION menu)ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁI/Q INTERCHANGEDRecovery of MPEG transport streamcorrect but data resulting from demappingwere inverted.If the QAM signal is converted to anotherfrequency, the spectrum is inverted if theconversion oscillator frequency is higherthan the signal frequency. The DDS200identifies this inversion and automaticallycorrects the decoded data information sothat a valid MPEG data stream is availableat the MPEG outputs. See also I/QINVERSION on page 2–36.ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁEQUALIZER UNLOCKED / OFF FREEZEÁÁÁÁÁÁÁÁÁÁÁÁ/ Equalizer unable to adapt to channel. OFF or FREEZE: set equalizer to AUTO(refer to EQUALIZER MODE onpage 2–34).UNSYNC: Conditions at the instrumentinput are so unstable that the equalizercannot synchronize. This happens in thecase of considerable level variations orwhen the transmission path of the QAMchannel has been changed.ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁIf a hardware-relevant error occurs, the SELFTEST ERROR CODE is displayedin the bottom line of the MEASURE menu. For evaluation of the SELFTESTERROR CODE, refer to Selftest (QAM) on page 4–3.ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁCommon to all MEASURE menus is that a noise generator can be connected.The noise generator in the OFF condition is activated with the ADD. NOISEkey. The desired value for the C/N ratio can now be entered in dB. When a noisesignal is added to the information signal, conclusions can be made about thesystem characteristics.DDS200 Digital Demodulation System User Manual 2–47