为何需要进行仿真？

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Simulation and Prototyping in the Design Process
In order to ensure a successful circuit design and mitigate costly and potentially dangerous design flaws, careful planning and evaluation must occur at every stage of the process. While there is no substitute for a physical prototype from which measurements can be taken and final behavior evaluated, circuit simulation provides a cost-effective and efficient method for identifying faults before moving to the more expensive and time-consuming prototyping stage. Therefore the best design processes include a good mixture of simulation and prototyping.

The prototyping stage helps engineers discover errors before a product goes to market. Including simulation in the design process reduces design errors and speeds the design cycle by allowing you to predict and better understand circuit behavior, experiment with what-if scenarios, optimize key circuits, and characterize difficult-to-measure properties.

Predict Circuit Behavior
The main purpose of simulation is to predict and understand the behavior of electronic circuits. Industry-standard SPICE simulation, as well as other types of circuit simulation such as microcontroller and VHDL co-simulation, fulfills this primary goal. Simulation is never meant to replace prototyping, since certain real-world effects, including cross-talk, electromagnetic noise, and spurious line noise, can be too difficult, time-consuming, or costly to model in simulation. However, simulation does provide a general understanding of the behavior and the characteristics of a given circuit. With this insight, engineers can discover and correct fundamental errors in their designs before moving to the more intensive prototyping phase.

Experiment with “What-if” Scenarios
Not only are modern circuit simulators good at giving a general prediction of behavior, but they allow components and topologies to be quickly modified, customized, and interchanged – replacing a given OpAmp or IC takes only a few clicks of a mouse. Designers have the ability to experiment with a variety of circuits in a simulated setting, enabling them to significantly reduce time spent spinning prototypes or bread-boarding each circuit. By exploring these what-if scenarios virtually, designers can lower the overall cost by creating designs with fewer components, more forgiving (and less expensive) component tolerances, or less expensive ICs.

Optimize Key Sub-Circuits
Today’s designs are more sophisticated than ever before. With the prominence of programmable devices such as FPGAs and FPAAs, the complete system-level simulation of sophisticated designs has become impractical and expensive, and in some cases even impossible. Notwithstanding, it is necessary to evaluate critical sections and sub-systems of a design for accuracy, functionality, and efficiency long before prototypes are built. Simulators can help designers to optimize subsystems, key sub-circuits, and components of a design.

Make Difficult Measurements Simple
Additionally, simulation provides the added benefit of giving designers insight into characteristics of a circuit that are difficult or impossible to measure. For example, Monte Carlo analysis gives designers insight into the effects of component tolerance on the overall operation of a circuit or design by running dozens or hundreds of iterations of an analysis with randomly varied component values. Performing a Monte Carlo analysis at a production or prototype level is simply economically not feasible, and so simulation provides a cost-effective window into this characteristic of a circuit.

Conclusion
While a prototype helps you to verify and validate your design in the real world, simulation helps you catch design errors before spending money and time on prototyping. These two stages go hand-in-hand to contribute to the overall success of almost any circuit design.

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