so that the input to {HEAD ~ said feedback element} is {TAIL ~ either the data input signal} or a combination thereof with the output of the feedback element, as determined by said control signal 
so that the input to { HEAD ~ said feedback element } is { TAIL ~ either the data input signal } or a combination thereof with the output of the feedback element , as determined by said control signal
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH