Spectroscopy done with visible or infrared radiation involves wavelengths of 10 to 10 Hz. Phototransducers (instruments that convert light to information readable by a computer) cannot make measurements that quickly. What is needed, then, is a way to make these high-frequency signals into low-frequency signals. For optical spectroscopy (such as infrared spectroscopy) the most common way to do this is by using a "Michelson interferometer".