But there is Mosaic impact in the enlarged picture because this method can't adequately attenuate the vertical frequency off the Base Band in the horizontal and vertical direction.

The spectrum of amplitude modulated signal are two half magnitude spectrums of base band signal positive and negative shifted by a carrier or R. F. frequency.

Then we perform digital pre-compensation method, which can be used in the processing of base band signal to reject image frequency and protect carrier leak to meet the application purpose.