It is possible to do whitening of the transmitted data to avoid long parts of consecutive 1’s or 0’s on the air (DC-balance). When using whitening in TX, the data is XOR-ed with a 9-bit pseudo-random (PN9) sequence before being transmitted. At the receiver end, the data is XOR-ed with the same pseudorandom sequence. This way, the whitening is reversed, and the original data appear in the receiver. The polynomial used is x^9+x^5+1 initialized to all 1’s. This sequence is also used when generating random data.

Whitening is not performed on the sync word. After a sync word is transmitted or received, the payload is XOR-ed as showed below.

Since the sync word is not whitened and the PN9 sequence always has the same initial value, the transmitter and receiver will always be in sync.