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RASSP Virtual Prototyping Application Note

2.0 Introduction to Virtual Prototyping

A prototype is any preliminary working example or model of a product, component, or system. It is often abstract or lacking in some details from the final version. Two main classes of prototypes are used in design processes: physical prototypes and virtual prototypes.

A physical prototype is a physical model of a product, component, or system. Traditionally, prototypes were physical models, as opposed to virtual-prototypes.

Examples of physical prototypes are: bread-boards, mock-ups, and brass-boards. Physical prototypes are characterized by fabrication times that typically require weeks-to-months and that typically require days-or-weeks to modify. Construction usually involves detailed design, lay out, board or integrated-circuit fabrication, ordering, and mounting via solder or wire-wrap. Additionally, programmable systems or parts require detailed target-software design of drivers and operating system, or programming PLAs, FPGAs, PROMS.

A virtual prototype is defined in the RASSP Taxonomy as a computer simulation model of a final product, component, or system. Unlike the other model type-names that distinguish models based on their characteristics, the term virtual-prototype does not refer to any particular model characteristic but rather it refers to the role of the model within a design process; specifically for:

To be useful in a larger system design, a virtual-prototype model should define the interfaces of the component or system under design. As with any model, a test-bench should exist for regressive verification.

In contrast to a physical prototype, which requires detailed hardware and software design, a virtual prototype can be configured more quickly and cost-effectively, can be more abstract, and can be invoked earlier in the design process. Another distinction is that a virtual prototype, being a computer simulation, provides greater non-invasive observability of internal states than is normally practical from physical prototypes. Comparatively, virtual prototypes introduce some risk due to the possibility of modeling inaccuracy or incorrectness.

Virtual prototyping is the activity of configuring (constructing) and using (simulating) a computer software-based model of a product, system, or component to explore, test, demonstrate, and/or validate the design, its concept, and/or design features, alternatives, or choices. Specifically, the act of using the virtual-prototype model as if it where an example of the final (physical) product.

Virtual-prototyping is synergistic with rapid-prototyping because it shortens product evolution cycles from days or weeks down to minutes. The designer can determine the effect of design changes on the behavior of the final system as quickly as it takes to edit a file.

next up previous contents
Next: 3 Example - SAR System Virtual Prototype Up: Appnotes Index Previous:1 Executive Summary

Approved for Public Release; Distribution Unlimited Dennis Basara