Direct Analytical Comparisons of Video Preamplifier Configurations for Optimum Signal-to-Noise Ratio Performance

A detailed analytical study has been made of the various factors affecting the band-limited signal-to-noise ratio in wideband video preamplifiers, where the signal source is essentially a current source and where the basic limitation on high-frequency performance is that of the input time-constant. This study involves an evaluation of the factors involved in creating "feasibility circuit models" preliminary to design optimization for specific requirements. Using identical overall frequency response forms, four basic types of amplifiers which correct for the input capacitance limitation are compared.