Which instrument would best help analyze the frequency components of a signal?

The spectrum analyzer is the instrument best suited to analyze the frequency components of a signal. It allows for detailed examination and display of the frequency spectrum of the input signal, breaking it down into its component frequencies. This analysis is crucial for identifying the presence and amplitude of various frequency components within a complex signal, enabling technicians to diagnose signal performance, distortion, or interference.

While an oscilloscope is often used to visualize waveforms in the time domain, it doesn't provide direct insight into the frequency domain without additional processing or techniques. A logic probe is useful for checking digital signals but does not provide frequency analysis. A wattmeter measures power but does not indicate how that power is distributed across different frequencies. Therefore, the spectrum analyzer stands out as the most effective tool for this purpose, providing the necessary functionality to assess and analyze frequency components directly.