Types of Conversions Cont

o    The original signal is sampled at equal intervals o    PAM uses a technique called Sample & Hold means At a given moment , signal level is read, then held briefly o    The  pulses  are  of  any  amplitude  (still  analog  not  digital).  To  make  them digital, we need PCM    Pulse Code Modulation o    Modifies pulses created by PAM to a complete digital signal o    Four Separate Processes: 9   PAM 9   Quantization 9   Binary Encoding 9   Digital/Digital Encoding 9   Quantization PCM's first step is Quantization "Quantization is a method of assigning integral values in a specific range to sampled instances" Figure  shows  a  simple  method  of  assigning  sign  and  magnitude values to quantized samples    Results of Binary Encoding

Each  value  is  translated  into  its  seven  bit  binary  equivalent.  The eight bit indicates the sign    Result of PCM

Figure shows the result of PCM of original signal encoded finally into a unipolar signal Only first 3 values are shown