A method of downscaling the travel-time-function of a reference body of mass mt in a spring-mass system with a spring providing a spring force when the spring-mass system is exposed to an acceleration field with an acceleration which moves the reference body against the spring force according to the travel-time-function is provided. In this method, the downscaling is done by coupling the reference body of mass mt to additional masses mr which are kinematically linked together in such a way that they do not react to acceleration field.