标签: rfic03y02

RFIC03y02L20021118EExdes(t)=cos(ωdest)xim(t)=cos(ωimt)xI(t)=cos(ωLOt)xQ(t)=sin(ωLOt)ЁEEωIFωIF=ωLOωdes=ωimωLOωdesuredωLOωimagesin(ωLOt)xdes(t)=cos(ωdest)xim(t)=cos(ωimt)cos(ωLOt)cos(ωLOt)E1┨xdes(t)sin(ωLOt)=sin(ωLOt)cos(ωdest)=?12()sin((ωLO+ωdes)t)+12sin(ωLOωdes)t12sin(ωIFt)xim(t)sin(ωLOt)=sin(ωLOt)cos(ωimt)=?12sin((ωLO+ωim)t)+12sin((ωLOωim)t)12sin(ωIFt)sin(ωLOt)xdes(t)=cos(ωdest)xim(t)=cos(ωimt)cos(ωLOt)cos(ωLOt)xdes(t)cos(ωLOt)=cos(ωLOt)cos(ωdest)=?12Ь……