Numerical device simulation of the composite triple-beat distortion of a cable television amplifier

The composite triple-beat (CTB) distortion of a cable television amplifier was simulated using numerical device simulation. The structures for the und erlying bipolar transistors were created using numerical process simulation . Subsequent time-domain device simulation was performed in a mixed device- circuit mode for a 77-carrier input signal with a random phase relationship between carriers. Using a novel mathematical technique, the turn-on transi ent of the amplifier was subtracted from the periodic part of the output si gnal in order to reduce the simulation time required to resolve the CTB dis tortion. A Fourier transform mapped the resulting signal into the frequency domain, where the CTB distortion could be determined directly. This simula tion methodology demonstrates the capability of correlating circuit level r adio frequency figures of merit with the process conditions in a technology .