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