Which instrument is used to test for noise problems?

The oscilloscope is an essential instrument for testing noise problems due to its capability to visualize electrical signals over time. By displaying waveforms, an oscilloscope allows engineers and technicians to observe noise characteristics such as amplitude, frequency, and distortion. In the context of noise issues, oscilloscopes can help identify unwanted signals or interference in a system, enabling the diagnostic process to target specific problems effectively.

While other instruments serve specific purposes, such as measuring voltage and current (the DMM), analyzing harmonics (the harmonic analyzer), or checking cable integrity (the TDR), they are not primarily designed for noise analysis. The oscilloscope's real-time visualization makes it integral for troubleshooting and understanding noise issues in electronic systems.