This module covers practical oscilloscope techniques with a focus on two critical pitfalls that can lead to misdiagnosis: sample rate limitations and aliasing.

Using a Nissan Pathfinder crank angle sensor capture as a real-world example, Tom demonstrates how a scope pushed beyond its sample rate limits can produce apparent signal dropouts on a perfectly healthy vehicle — and how that can send you down the wrong diagnostic path.

The bulk of the module is dedicated to aliasing: what it is, why it happens, and how to recognize and avoid it. Topics include:

• The Nyquist theorem and its practical implications for automotive scope work
• Live demonstration of aliasing using a 488 Hz signal generator and a Fluke 97
• How to identify the aliasing threshold using the time base and a sample rate calculator
• Comparison of a small-buffer scope versus a large-buffer scope (Pico 3423) on the same signal
• The role of memory buffer size in a scope's ability to maintain adequate sample rates at longer time bases
• Min/max mode as a partial workaround and its limitations