the first circuit is coupled to the oscillator through the second input node and configured for detecting a phase/frequency difference between the externally provided clock signal and {HEAD ~ an internal clock signal} to be generated by {TAIL ~ the oscillator}, and 
to be generated by
the first circuit is coupled to the oscillator through the second input node and configured for detecting a phase / frequency difference between the externally provided clock signal and { HEAD ~ an internal clock signal } to be generated by { TAIL ~ the oscillator } , and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH