This paper describes an executable HDL that extends the capabilities of the digital VHDL language for FPGA design. FPGA designers are familiar with HDL-based, requirements-driven design methodologies for digital electronics. But how can requirements be expressed for a system that, while it contains digital elements, is fundamentally non-digital? VHDL-AMS is the perfect language for providing continuity in design and verification at all levels: functional specifications; architectural partitions; and component implementations. It is an undiscovered asset for FPGA designers – a powerful tool to define and verify requirements in a non-digital context.