JAJSEY1 April 2019 ADC12DJ5200RF
ADVANCE INFORMATION for pre-production products; subject to change without notice.
The DDC contains a complex numerically-controlled oscillator (NCO) and a complex mixer. Equation 3 shows the complex exponential sequence generated by the oscillator.
The frequency (ω) is specified by a 32-bit register setting (see the Basic NCO Frequency Setting Mode section and the Rational NCO Frequency Setting Mode section). The complex exponential sequence is multiplied by the real input from the ADC to mix the desired carrier to a frequency equal to fIN + fNCO, where fIN is the analog input frequency after aliasing (in undersampling systems) and fNCO is the programmed NCO frequency.