Pulse modulation techniques can encode an analog signal for transmission. This document discusses several techniques including: - Pulse-amplitude modulation (PAM) which varies pulse amplitudes based on sample values of the message signal. - Pulse code modulation (PCM) which assigns a binary code to each analog sample. PCM is commonly used in digital communications systems. - Delta modulation which transmits one bit per sample indicating if the current sample is more positive or negative than the previous. It requires higher sampling rates than PCM for equal quality.