What is Pulse Code Modulation (PCM)?

PCM is a method for digitizing analog signals through three steps: Sampling (measuring signal at regular intervals at Nyquist rate or higher), Quantization (mapping samples to discrete levels, introducing quantization noise), and Encoding (converting quantized values to binary). Standard telephone PCM uses 8kHz sampling and 8-bit quantization for 64 kbps. PCM enables digital transmission advantages: noise immunity, regeneration, easy multiplexing, and digital processing. Companding (A-law, mu-law) improves dynamic range for voice signals.