RFDAC Convertor Design Using First Order Holder

A noise shaped directed digital to RF converter based on first order hold pre-filtering is presented. The converter consists of a 400MS/s digital ΔΣ modulator followed by a 2.4-GHz digital to Radio Frequency (RF) converter. The proposed structure attenuates the out-of-band spectral and relaxes the design of ΔΣ and RF-Filter. The technique is based on using First Order Hold filter in respect to use the conventional Zero Order Hold filter. The simulation result shows 16dB image rejection improvement. Also, the modulator achieved 79dB of Signal to Noise Ratio in 5MHz of band width. The output power is -4dBm while power consumption is about 2.55mW.