coded diphase (CD)
Coded Diphase(CD) is a transmission method for baseband. This method works with phase shift keying whereby the level value changes either with each clock pulse or with half the clock frequency while the digital state remains constant.
When transmitting zeros, a bit sequence of the clock signal is sent; for binary ones, the clock frequency is switched to half.
The Coded Diphase method is independent of the digital signal and always transmits a bit sequence at continuous digital levels: at zero the clock frequency, at one the half clock frequency.