An apparatus for adjusting a phase difference between a positive signal of {TAIL ~ a differential signal} and a negative signal of {HEAD ~ the differential signal}, the apparatus comprising: 
An apparatus for adjusting a phase difference between a positive signal of { TAIL ~ a differential signal } and a negative signal of { HEAD ~ the differential signal } , the apparatus comprising :
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH