Harvard biphase

Harvard biphase is a magnetic run length code for encoding magnetic tape. Harvard biphase has previously been used for digital flight data recorder where 12-bit words per second are recorded onto magnetic tape using Harvard biphase code. For Harvard biphase, a phase transition in the middle of the bit cell indicates that the bit is 1. No transaction indicates that the bit is 0. There is also a phase transition at the start of each bit cell.