Spectre MDL: Turn Simulation Results into Reusable Measurements

10 Sep 2026 • 3 minute read

Running a simulation is only half the job. Engineers must also extract useful measurements from the resulting waveforms.

Imagine characterizing an amplifier across different voltages and temperatures. Manually checking gain, rise time, duty cycle, and threshold crossings for every run can become repetitive. Spectre Measurement Description Language, or Spectre MDL, helps automate this work.

What Is Spectre MDL?

Spectre MDL is a scripting and measurement language that works with the Spectre Circuit Simulator and Virtuoso Visualization and Analysis.

It can help you:

Create reusable measurement definitions
Run simulations in batch mode
Pass parameters into measurements
Automate sweeps using loops
Search for circuit-performance boundaries
Evaluate additional measurements from existing simulation results

A Simple Example

An engineer may want to measure the DC gain and zero-dB crossing frequency of an amplifier:

The measurement alias connects an analysis with one or more measurement expressions. It can then be reused in compatible simulation flows.

Why Use Spectre MDL?

Reuse Measurement Logic

Measurements such as gain, rise time, fall time, RMS, duty cycle, phase margin, and threshold crossing can be defined once and reused.

Automate Characterization

The foreach statement supports repetitive simulations and sweeps. The search statement varies a parameter until a specified circuit condition is reached.

Reduce Unnecessary Simulation

The autostop feature can stop a transient simulation after sufficient data is available for the requested measurements.

Measure Existing Results

Postprocessing mode lets you evaluate updated or additional measurements using an existing simulation results database, provided the required signals were saved.

Spectre MDL turns measurement intent into an executable and reusable part of the simulation flow. Instead of repeatedly inspecting waveforms, engineers can automate measurements, sweeps, searches, and postprocessing. For anyone working with Spectre simulation and analog characterization, MDL offers a practical path from waveforms to repeatable results.

Want to Learn More?

For lab instructions and a downloadable design, enroll in the online training courses of your interest:

Spectre Simulator Fundamentals S4: Measurement Description Language Training

Training is also available as a blended or live class.

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Related Resources

Training Bytes (Video Channel)

Spectre MDL (Video Channel)

Online Course

Spectre Simulator Fundamentals S4: Measurement Description Language Training

About Knowledge Booster Training Bytes

"Knowledge Booster Training Bytes" is an online journal that provides information about Cadence Training videos, online courses, and upcoming webinars that are available on the Cadence Learning and Support portal. This blog category offers direct links to these videos, courses, and other related materials on a regular basis.

Sai Darshan S Nishani

Sr. Education Application Engineer