Guest columnist Mike Woodward, communications industry marketing manager at The MathWorks, describes how digital and analogue circuit simulation techniques can be combined at the system level.
Design tools are often targeted at a single design domain, for example analogue design, and don’t work well with tools for other design domains. This makes interaction between engineering teams more difficult than it needs to be.
This type of ‘silo development’ also introduces verification inefficiencies. It pushes integration testing toward the end of the design process, when bugs are more expensive to fix.
Adding to this is the tendency of engineering teams to write test harnesses from scratch, instead of using trusted models created earlier in the design process.
Linking design domains
To link different design disciplines, we need to design and simulate different design domains in the same model. This requires a platform that can simulate different types of systems at the same time.
Multi-domain system-level design platforms do exist, combining different simulation types and tools, allowing the user to build one system model combining the behaviours of all subsystems.
Multidomain simulation can rule out unworkable designs at the start of the project. Effectively this can bring verification to project inception.
Linking different tools
To re-use the “golden reference” system model for verification, it is necessary for the system-level design platform to have run-time co-simulation links to implementation tools that enable us to examine the dynamic behaviour of systems.
The tools, from different vendors, can exchange data at each simulation time step, enabling simulation of the dynamic behaviour of the analogue-digital system. Similar co-simulation links are also available for other popular analogue and circuit-level simulation environments.
This co-simulation offers three benefits. First, it re-uses the system-level model as a test bench during the implementation phase of the project.
Second, the system model acts as a common simulation platform between different disciplines, enabling collaboration via a common model all can understand and use.
Third, we can benefit from a more integrated development approach while still using existing tools, reducing adoption risk. This early verification has yielded large savings in several real projects.
The design flow we are advocating starts with a system-level design and integrates with existing flows to offer efficiency improvements without the risk of revolutionary change.
At the early stages of the project, the model unifies different design domains and enables us to make design trade-offs. This brings verification to the start of the design process and links the different design teams via a common platform that enables earlier and more detailed testing.
Finally, we re-use the system model as a test harness and golden reference for verification, comparing the physical wireless prototype with the system model golden reference.
Engineering managers today face the challenge of co-ordinating geographically dispersed teams working on different parts of an overall system using different, disconnected tools.
Engineering teams can best address this challenge by adopting system-level design, while expressing some lower-level details as text.
Whether small or large, geographically distributed or located in the same office, engineering teams struggling with discontinuities in their design workflow can apply the technologies discussed here to streamline and accelerate the development of complex signal processing and communications systems.
The Mathworks