In the method, a mixed signal is provided by mixing the tone signal with {HEAD ~ a reference signal} alternating at a frequency fm between {TAIL ~ values} related to sin fr and cos fr, where fr is a frequency substantially equal to fd and where fm is substantially greater than fr 
alternating between
In the method , a mixed signal is provided by mixing the tone signal with { HEAD ~ a reference signal } alternating at a frequency fm between { TAIL ~ values } related to sin fr and cos fr , where fr is a frequency substantially equal to fd and where fm is substantially greater than fr
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL 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