FM Stereo Signal Generator Design Method by Fully Differential Difference Amplifier

摘要

PURPOSE: A method for designing an FM stereo signal generator using a fully differential difference amplifier is provided to improve immunity from noise in a process for generating a stereo signal by converting left and right audio signals to fully differential signals. CONSTITUTION: A folded-cascode type amplifier is used in a fully differential difference amplifier. Four inputs are formed by two differential input terminals. Negative inputs of each terminal are crossed each other. A capacitor is used for interrupting direct current element of an input signal. A single input signal is changed to a differential signal by the fully differential difference amplifier. Signals of L+, L-, R+, and R- are used as inputs of the fully differential difference amplifier having a voltage gain of 0dB. A sum signal and a difference signal are obtained by combination of L+ and R- signals and L+ and R+ signals, respectively.