How Does a Spectrum Analyzer Work?
Engineers and scientists working with sound, radio and other phenomena use spectrum analyzers to find the energy makeup of a signal. A spectrum analyzer is an electronic device that breaks a complex signal into frequency components and displays the results graphically. A spectrum analyzer can use either of two main methods of analyzing a signal: a physical method and a numerical analysis method. The physical method works by sweeping the input signal with a narrow bandpass filter. The filter’s center frequency is controlled by a rising sawtooth waveform, so it continually scans the input. The output of the filter at any given moment will be the strength of the energy of the signal at the filter’s frequency. When the filter’s output is captured on an oscilloscope screen in sync with the controlling sawtooth, the result is a display of the signal’s spectrum. The numerical analysis method involves converting your signal into a data stream and doing some number crunching. With the kind of p
