DESIGN of a PULSE GENERATOR CIRCUIT for UWB COMMUNICATIONS

Generation of very short pulses with a pulse width in the order of a few nanoseconds or less is a requirement for an UWB communications system. A pulse generator circuit based on the step-recovery effect of an RF transistor has been designed for the 0-960-MHz UWB system, and is presented in this paper. The pulse generator includes a linear RF amplifier with common-emitter topology and a high-pass filter following the amplifier. Input of the RF amplifier is driven by a clock signal provided by a function generator. Amplifier output includes positive amplitude and negative amplitude pulses due to rising and falling edges of the collector-emitter voltage of the transistor, respectively. Amplifier output is then fed to a high-pass filter. Low-frequency transitions are further filtered out, and the output of the high-pass filter is a pulse train consisting of very short pulses. The pulse width has been measured as about 2.5 ns using a 300-MHz digital oscilloscope