Frequency hopping is used with which type of transmission?

Frequency Hopping Spread Spectrum (FHSS) is a specific wideband transmission method where the carrier frequency is rapidly changed, or 'hopped,' across a wide band of frequencies. The transmitter and receiver hop in sync according to a mathematically predetermined pseudo-random pattern. Other options like Packet, AMTOR, and RTTY are traditional narrowband digital modes or protocols. They do not distribute their signal energy across a wide frequency band by rapidly changing frequencies, which is the defining characteristic of spread spectrum technology.