Transfer functions are used in the design of electronic systems such as filters, power supplies, and other control systems. Frequency-domain analysis of a transfer function involves the Laplace transform. This article explores the implementation of a transfer function in LTspice, compares the ideal response to a modeled implementation, and provides several useful examples along the way. Files are available to aid in the understanding and implementation of this topic.
Transfer functions are used when we want to analyze how the output of a system changes depending on the input. The system could be the output voltage of a resistor divider or the speed of a car when you step on the gas. To analyze a system, we want to know how its output amplitude and phase compare with the input over frequency.