yquist rate. When we sample at 245.76 MHz, the processing gain is calculated as 10*log10(245.75/100) = d dB. Aggregate, it looks like we need a minimum of 29 + 9 + 8 + 2-4 = 44 dB. However, keep in mind that the DAC performance is defined by a secondary factor which is the requirement to provide an output signal with sufficiently low ACLR - per 3GPP specs better than -45dB leakage to the adjacent channel. This -45dB number defines a lower bound to the perfor- mance of the DAC say 60 dB or 10 ENOB to have implementation margin. ACLR is also impacted by the intermodulation distortion (nonlinearity) of the DAC which causes spectral regrowth. The above example is a case of a zero-IF interface where the data converter is operating in what is called the 1st Nyquist zone. This zone is defined as the bandwidth between DC and 1/2 of the sampling frequency Fsample Similarly, the 2nd Nyquist zone is defined as 1/2 Fsample Fsample, the 3rd Nyquist zone as Fsample 11/2 Fsample, and SO on. The signal in these other (nonprimary) Nyquist zones can still be captured by the data converter but they are combined with (folded into) the baseband signal. If we filter out all other input signals to make sure that only the signal from the desired Nyquist zone reaches the data converter, we can convert the signal between analog and digital domains. For a data converter to be used for undersampling (or subsampling), its input bandwidth needs to be wide enough to be able to capture the target RF bandwidth. Such data converters are commonly referred to as RF data converters and are used for IF and RF data use-cases as we described earlier. There is a similar discussion on the digital predistortion (DPD) feedback path that also includes an ADC which we will discuss later.Andersen et al. 8 shows how Zhu's general sam- pling theorem9 can be applied to PA characterization, thus removing the requirement of feedback ADC bandwidth to be wide enough to capture all out-of-band distortion. Radio frequency subsystem The interface between the modem and 