A spectrum analyzer is a device used to measure and display the frequency spectrum of signals. It helps visualize the amplitude of signals across different frequencies, allowing users to identify and analyze various components within a signal. This tool is commonly used in fields like telecommunications, audio engineering, and electronics to ensure signals are within desired parameters. Spectrum analyzers can be either analog or digital, with digital models offering more advanced features and greater accuracy. They are essential for troubleshooting and optimizing systems by detecting unwanted noise or interference. Overall, spectrum analyzers play a crucial role in maintaining signal quality in various applications.