Impedances of different stages can interact and affect the performance of your precision signal chain. Signal Chain Designer, a web-based tool built to create and simulate complex precision signal chains, helps you solve common design issues such as knowing when output impedance reduces amplifier gain and helps you work around it to meet your system level requirements.
Signal Chain Designer Web-based Tool
Signal Chain Designer demonstrates how the output impedance of a preceding stage can directly influence the effective gain of the amplifier that follows. When the previous stage’s output impedance is in the same order of magnitude as the input impedance of the amplifier, the latter loads the former, creating an unintended voltage divider that reduces the delivered signal amplitude.
Amplifier Gain Plot in Signal Chain Designer - Example Scenario where Output Impedance of the Previous Stage Affected the Amplifier Gain
This loading effect leads to lower than expected gain, which can be seen in the tool's gain vs. frequency plot, as well as the nominal gain in the DC error view, showing that impedance interactions altered the intended transfer function.
Signal Chain Designer Warning on Gain being Different than Requested
These effects highlight the importance of proper impedance planning in ensuring system‑level gain accuracy. This is one of the many design challenges that Signal Chain Designer tool helps users solve.
For deeper understanding of how these impedance interactions behave in signal chain scenario, as well as a demonstration of how the Signal Chain Designer tool visualizes gain error, loading effects, and frequency response, see this video Signal Chain Designer: Watch out for Output Impedance which provides an excellent, detailed walkthrough.