1. A method for generating coverage data for a switch frequency of hardware description language (HDL) signals, comprising the steps of: providing a HDL hardware description model within a register transfer level, providing a filtering algorithm for signals occurring in the HDL hardware description model, extracting signals from the HDL hardware description model according to said filtering algorithm in order to get relevant signals, performing a simulation process on a compiled representation of the HDL hardware description model, performing a checking routine for the relevant signals in every cycle and storing the relevant signals in a data base.