Pulse Code Modulation (PCM) and A-law/μ-law PCM for Audio Compression Codec Process

This experiment demonstrates the detailed steps of simulating Pulse Code Modulation (PCM) and A-law/μ-law PCM audio compression codec processes using MATLAB. PCM (Pulse Code Modulation) is an encoding method that converts analog voice signals to digital signals through waveform encoding, which involves quantization and encoding of sampled signal values. The quantization process maps an infinite set of continuous amplitude values to a finite set of discrete amplitudes, while encoding uses binary numbers to represent these quantized values. Internationally standardized PCM adopts folded binary codes to ensure toll-quality transmission. Based on quantization techniques, PCM is divided into two main categories: uniform quantization PCM and logarithmic PCM. For logarithmic PCM, A-law and μ-law encoding have been established as international standards, providing efficient audio compression and decoding capabilities through algorithms that implement non-linear quantization curves, companding techniques, and digital signal reconstruction methods in code.