Manchester decoder

The Manchester or biphase code is used very frequently, (examples include hard disk drives and networks), because the code contains both the data and the clock and is therefore very compact. In addition, there are only two frequencies present and never contains low frequencies. A logic zero is defined as a ‘0 to 1 edge’, a logical one is represented by a falling edge. This works well as long as the data is continuously changing, but when multiple zeros or ones appear in a row, it becomes necessary to insert additional edges between the original rising or falling edges.