There are 2 standards
IEEE standards and GE Thomas standards.
In IEEE 802.3 '1' is represented by low-to-high and '0' represented by high-to-low .
In G.E. Thomas' convention '1' by high-to-low transition and '0' is expressed by a low-to-high transition .
In Gate we follow IEEE standards generally .
In differential manchester if next bit same as current bit we will not invert if it is different then we will invert the waveform.