Design of radiated comb generator using single-ended positive emitter coupled logic (PECL) D Flip-Flop

Abstract

Comb generator has been an indispensable tool in the electromagnetic compatibility (EMC) testing field. It is used for calibration and self checking of the test systems. This paper presents a rarely explored yet promising radiated comb generator that makes use of a single-ended PECL D Flip-Flop as the pulse forming component. Measurements show that the generated pulses typically possess fall time and rise time of 330 ps and 410 ps, respectively. Its frequency accuracy is offset by +24 ppm, which is common for crystal oscillators. When being connected to a monopole rod antenna, the comb generator is able to generate radiated emissions that have smooth envelope profile up to 1000 MHz frequency range.