The document discusses bandwidth utilization techniques including multiplexing and spreading. Multiplexing allows simultaneous transmission of multiple signals across a single data link by dividing the bandwidth into channels. Efficiency is achieved through multiplexing while privacy and anti-jamming is achieved through spreading techniques that add redundancy such as frequency hopping spread spectrum and direct sequence spread spectrum. The document provides examples and figures to illustrate concepts such as frequency-division multiplexing, time-division multiplexing, and digital signal hierarchies.