--- In [email protected], "Adnan Yusuf" <[EMAIL PROTECTED]> wrote: > > This one is a basic one. How does IQ sampling double the sampling > rate, I just cant grasp the concept. HELP!! > > Adnan Yusuf >
A purely real signal has a frequency spectrum that is symmetric. (If you do a Fourier transform, the left half plane is a mirror copy of the right half plane). If you downconvert to zero Hertz a RF signal at the carrier frequency where the right and left of the carrier frequency are asymetric, you get corruption. For a IQ downconversion sampling, the signal's frequency spectrum is not constrained to be symmetric. The frequency spectrum at the carrier frequency is simply shifted down to 0 Hz. Frank
