A new UWB pulse generator for narrowband interference avoidance

In this paper a new IR-UWB pulse generator circuit is proposed which is capable of solving the coexistence problem of narrowband and ultra wideband communication systems. This is done by creating a notch in the PSD of the generated UWB signal and adjusting its center frequency at the frequency of the narrowband interference. Using a triangular pulse generator, a triangular signal is generated and applied to the proposed circuit which consists of three main function blocks including quadratic, exponential and differentiator circuits. A differential pair MOS transistors in sub threshold region is utilized in order to realize the exponential block. The circuit is designed using a 0.18-mm RF CMOS technology. The notch is produced with the center frequency of 5 GHz. Simulation results verify the effectiveness of the proposed pulse generation technique where simulated signals are in accordance with mathematical analyses. The resultant IR-UWB signal also satisfies the FCC mask requirements.