Encoder

The major steps involved in PCM are sampling, quantizing, and encoding.

Encoder:

• An encoder performs the conversion of the quantized signal into binary codes.
• This unit generates a digitally encoded signal which is a sequence of binary pulses that acts as the modulated output.
• It is a binary encoder thus generates a binary code sequence. That is transmitted through the transmission path.
• The encoder is a combinational logic circuit that converts an active input signal into a coded output signal.
• It has n input lines, only one of which is active at any time, and m output lines.
• It encodes one of the active inputs to a coded binary output with m bits.
• In an encoder, the number of output lines is less than the number of inputs.
• If an encoder has n input lines and m output lines then n<= 2m.