Patent ID: 8013653

Claim:
A system for eliminating intra-pair skew, comprising: a phase difference measuring apparatus, adapted to detect phases of differential signals inputted to the phase difference measuring apparatus to obtain a transmission delay difference between the differential signals; a delay adjusting apparatus, adapted to perform delay adjustment of the differential signals inputted to the delay adjusting apparatus according to the transmission delay difference obtained by the phase difference measuring apparatus, and output the differential signals after the delay adjustment; at least two cross switches, adapted to switch the differential signal which arrives earlier than the other differential signal to the delay adjusting apparatus according to the transmission delay difference obtained by the phase difference measuring apparatus; and a delay adjustment controlling apparatus, adapted to receive the transmission delay difference outputted by the phase difference measuring apparatus, and control the cross switches and the delay adjusting apparatus according to the transmission delay difference, to control the delay adjustment of the differential signals; wherein the delay adjustment controlling apparatus is implemented using a state machine, and states of the state machine comprise: a first state, where an electrical signal P in the differential signals arrives earlier than an electrical signal N in the differential signals, a delay of the electrical signal P is increased and a delay of the electrical signal N is maintained; a second state, where the electrical signal P and the electrical signal N in the differential signals arrive simultaneously, the delay of the electrical signal P and the delay of the electrical signal N are maintained; and a third state, where the electrical signal N in the differential signals arrives earlier than the electrical signal P in the differential signals, the delay of the electrical signal N is increased and the delay of the electrical signal P is maintained.