According to the invention, {HEAD ~ the undesired periodic noise} is filtered out of {TAIL ~ the input signal} during the digital signal processing , after the conversion of the digital signal into the frequency domain 
is filtered out of
According to the invention , { HEAD ~ the undesired periodic noise } is filtered out of { TAIL ~ the input signal } during the digital signal processing , after the conversion of the digital signal into the frequency domain
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH