Chip (CDMA)
（重定向自Spreading factor）
In digital communications, a chip is a pulse of a direct-sequence spread spectrum (DSSS) code, such as a Pseudo-random Noise (PN) code sequence used in direct-sequence code division multiple access (CDMA) channel access techniques.
In a binary direct-sequence system, each chip is typically a rectangular pulse of +1 or –1 amplitude, which is multiplied by a data sequence (similarly +1 or –1 representing the message bits) and by a carrier waveform to make the transmitted signal. The chips are therefore just the bit sequence out of the code generator; they are called chips to avoid confusing them with message bits.