Glossary definition of 'IMD difference-tone measurement'

An IMD measurement method (e.g. CCIR) wherein two tones, of equal amplitude, close together in frequency (e.g. 19kHz and 20kHz, or 14kHz and 15kHz for band-limited systems) are applied to the EUT. The amplitude of the distortion component at the difference frequency (e.g. 1kHz) is measured, usually relative to one of the original tones.