Definitions for "Frequency hopping spread spectrum"
Keywords:  fhss, narrowband, hop, wlan, spectrum
A type of radio communications in which the transmitter and receiver hop in synchronization through a pre-arranged pattern of frequencies. This reduces the effect of narrow band noise. FHSS modulates information onto a narrowband carrier signal that "hops" in a pseudo-random but predictable sequence from frequency to frequency. This technique reduces interference because a signal from a narrowband system will only affect part of the spectrum. Transmission frequencies are determined by a so-called spreading, or hopping, code. Receivers must be set to the same hopping code and must listen to the incoming signal at the right time and correct frequency in order to properly decode the signal. FCC regulations require manufacturers to use 75 or more frequencies per transmission channel with a maximum dwell time (the time spent at a particular frequency) of 400 ms.
A spread spectrum modulation technique whereby the radio transmitter frequency-hops from channel to channel in a predetermined but pseudorandom manner. The RF signal is dehopped at the radio receiver using a frequency synthesizer controlled by a pseudorandom sequence generator synchronized to the transmitter's pseudorandom sequence generator. A frequency hopper may be fast-hopped, where there are multiple hops per data bit, or slow-hopped, where there are multiple data bits per hop.
A type of spread-spectrum radio transmission in which the transmitter and receiver hop in synchronization from one frequency to another according to a prearranged pattern.