What is direct-sequence spread spectrum?

Direct-Sequence Spread Spectrum (DSSS) works by mathematically combining the original data with a much faster pseudo-random binary bit stream, often called a "chipping code." This fast bit stream phase-shifts the carrier, which effectively spreads the signal's energy across a much wider bandwidth than the original data required. When the signal reaches the intended receiver, the exact same synchronized bit stream is used to "despread" the signal and recover the original data. This technique is widely used in modern digital communications, including Wi-Fi and GPS. If you see an option about a pseudo-random list of channels, that describes frequency hopping, not direct sequence.