Effectively, there is no theoretical limit to the applicability of the invention, although practical difficulties may occur at {HEAD ~ extremes} of {TAIL ~ low and high frequency} 
Effectively , there is no theoretical limit to the applicability of the invention , although practical difficulties may occur at { HEAD ~ extremes } of { TAIL ~ low and high frequency }
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 REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL