We present a general mathematical model of signals for efficient and accurate simulation of analog and mixed signal (AMS) systems. It relies on signal coding and parameterization and allows heterogeneous system specification at different abstraction levels, as well as, the operational computation of continuous time systems' dynamical behavior. In particular, we derive a matrix for operational subdivision of continuous signals and use it to capture accurately the interaction between continuous and discrete time systems. A key advantage of this signal representation is that continuous signal monitoring and analysis can be performed more efficiently, speeding up system verification. We implemented the proposed modeling approach in SystemC AMS 2.0 to exploit the dynamic reactive behavior of TDF MoC for accurate synchronization between the digital and analog system parts. With the example of a PLL system we evaluate the capabilities of our implementation to cope with heterogeneous designs at different design abstraction levels. The experimental results show a significant simulation speedup for high accurate models.