An integrator includes a source of {TAIL ~ current} responsive to {HEAD ~ the signal} to be integrated 
An integrator includes a source of { TAIL ~ current } responsive to { HEAD ~ the signal } to be integrated
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH