Differential Biphase Coding (DBP) is an edge coding. Only the binary zeros are coded as a half-bit period. The amplitude changes from "0" to "1" at half the bit period duration and falls back to "0" with the following edge. If a binary one is present, the coding pattern remains unchanged. To enable the receiver to generate a clock recovery from the data signal, the DBP signal is inverted at the start of each period.