From the equation 5, it can be known that {HEAD ~ the output signal} y4 of the second synthesizer 215 includes {TAIL ~ a second order intermodulation component}, a third order intermodulation component and a fourth order intermodulation component, and so forth 
includes
From the equation 5 , it can be known that { HEAD ~ the output signal } y4 of the second synthesizer 215 includes { TAIL ~ a second order intermodulation component } , a third order intermodulation component and a fourth order intermodulation component , and so forth
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL 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