This contribution presents a time-domain model of the skin depth effect in a lossy transmission line. The model was developed and implemented in VHDL-AMS for a two wire edge coupled line but it is general and can be used for other types of lossy transmission line and high-frequency applications with skin depth effect. The salient feature of the model is the use of signal variation rate instead of frequency in the signal dependent resistance that models the skin depth losses. VHDL-AMS simulation experiments are presented to validate the model