spectrum analyzer ES8821 used in telecommunication,broadcasting,CATV and EMC testing field as the most ... and ES8821Q, which fully utilize DSP (Digital Signal Processing) technologies. They are widely used in telecommunication, broadcasting, CATV and EMC testing field ... /64/128/256QAM/QPSK modulation type and other key parameters in digital signal measurement, for instance, MER, EVM, and Pre/Post BER ...