This paper comprehensively studies the difference between max output level "Somax" and nominal output level "Sa" of CATV amplifier, and analyzes the time and condition that the formulas based on "Somax "and Sa being applied.

In this paper, the author discussed the history and cause of the variation of the design method for the maximum output level of CATV amplifiers, analyzed the difficulty to accurately design the output level, and proposed a method which is based on the original parameters of the amplifier module to solve the problem in designing the output level and calculating the distortion.