DDS-Based Flexible UWB Pulse Generator Using Anti-Nyquist Sampling Theorem

Abstract

Abstract A real all-digital and all-coherent arbitrary ultra wideband pulse generator is presented. The generator is a multi-core & single-channel (MCSC) direct-digital-synthesizer (DDS) which consists of 16 sub-cores and a high speed digital analog converter AD9739. The ultra-wideband pulses are generated according to the proposed anti-Nyquist sampling theorem. Their frequencies are aliasing in the first and second Nyquist zones. By purposely aliasing the spectrum, the output bandwidth can be increased greatly. All the parameters including pulse width, bandwidth, amplitude, pulse type, pulse repeat frequency and modulation are user-controlled on-the-fly. In order to test the performance, monopole pulse, monocycle pulse and two 4th order Gaussian pulses are generated. The monopole pulse whose pulse rate can achieve 2.5 GHz has a 10% pulse width of 450 ps, a 200 mV peak amplitude and a -10 dB bandwidth of 2.15 GHz.