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 5GHz. 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.