A PPM Gaussian monocycle transmitter for ultra-wideband communications

A Gaussian pulse generator incorporating a pulse position modulator for use in an impulse radio ultrawideband system is described. The pulse generator is preceded by a programmable pulse position modulator and comprises a cascade of complex first-order systems, which, in turn, are made up of differential pairs employing partial positive feedback. The resulting PPM Gaussian pulse generator is designed in IBM 0.18 /spl mu/m Bi-CMOS IC technology. Simulations predict the correct operation of the circuit for supply voltages of 1.8 V and a power consumption of 30 mW. The output monocycle indeed approximates a Gaussian monocycle, having a pulse duration of about 250 ps. Proper modulation of the pulse in time is confirmed.