A spread signal is a signal that is used for "spreading out" a communication band when a digital signal is transmitted wirelessly. When a signal is transmitted on a normal communication band, noise and interference from other channels are received, and the signal is subsequently degraded. In contrast, if the communication band is deliberately spread out, the effect of noise and other-channel signals can be reduced. When the signal is received, the same "spread code" used at the time of transmission is used, and the original signal is restored to its original state.
