Square-Wave Analysis of Compensated Amplifiers

A complete analysis of a single-stage compensated video-frequency amplifier is presented. In this amplifier high-frequency compensation is obtained by the use of a shunt peaking coil in series with the plate load resistance, and low-frequency compensation is obtained by using a resistance-capacitance network in series with the plate load resistance. Both square-wave and sine-wave input voltages to the amplifier are considered. The square-wave analysis consists of a determination of the output wave shape when a symmetrical square wave is applied to the input. Equations for the output wave shape are derived and put in such a form that the output wave shape may be plotted for any desired frequency of input square wave. Output wave shapes are drawn for a number of typical operating conditions, and the corresponding frequency- and phase-response curves are drawn for comparison. The effect of the cathode impedance, assumed negligible in the square-wave analysis, is considered briefly in a separate section, and its effect on low-frequency compensation is discussed. Derivations of many of the equations used are found in the Appendix.