A Novel Circuit Architecture for Generating Narrow Pulses via Spectrum Stitching

In this paper, a novel circuit architecture is proposed to generate narrow pulses with high flexibility and without high cost. The desired narrow pulse signal is obtained via combining multiple sub-signals. The bandwidth of individual sub-signals is much smaller than the bandwidth of the desired pulse signal, and thus the sub-signals can be generated by low-speed digital-to-analog converters (DACs). When the sub-signals are combined, their spectra are stitched into the wideband spectrum of narrow pulse signal. Theoretically, arbitrary pulse waveforms can be synthesized through the proposed “spectrum stitching” technique without resorting to high-speed DACs, as long as the sub-signals are synchronized among each other in time. A prototype circuit is implemented to verify the fundamental scheme of the proposed “spectrum stitching” technique. The experimental results demonstrate that, Dirichlet pulses with temporal width of approximately 4 ns are successfully synthesized through combining the outputs of a regular 80-MHz waveform generator. In addition, numerical and experimental results indicate that, the proposed “spectrum stitching” circuit architecture is quite insensitive to various practical errors.