1.ADC PCM The unit doing the conversion is called ADC. There are 2 important operations, 1. discrete in TIME; 0→[ 2. discrete in Value; xn川]→x[n Analog waveform Discrete sequence Digital sequence Sampling Quantizing t1:-04.88y -5 t2:+21.43V 21 UESTC-Digital transmission through the AWGN channel Prof李晓峰 8