unrelated to the input signal. As a signal result, THD+N can be considered all signal content in the DUT response that is not contained in the stimulus. Signal-to-Noise Ratio (SNR): the ratio of desired signal to unwanted noise coming from a DUT, expressed in dB. Crosstalk: the unwanted presence of a signal from one audio channel as it appears in other audio channels of a DUT. Since this is a ratio, it is expressed in dB. Phase: the relationship in time between two signals of identical frequency, expressed as a fraction of the period of the signal. This is usually expressed in degrees, with one complete cycle of a sinusoidal signal being 360 degrees. Intermodulation Distortion (IMD): Distortion that is the result of non-linear mixing of two or more signals, typically two sine-waves at different frequencies or the sum of a sine-wave and square-wave. In addition to distortion products at harmonic multiples of the frequencies, products are also found at multiples of the sums and differences of the original frequencies. Time domain display: Equivalent to an oscilloscope display of the signal, showing instantaneous amplitude as a function of time. See also Audio system measurements Distortion References Understanding the Decibel in Audio Measurements SINAD measurements Using Audio Analyzer Two-Way Radio Testing with Audio Analyzer Introduction to the Six Basic Audio Tests How to Write (and Read) Audio Specifications The Audio Measurement Handbook Acoustic Transducer Testing Audio electronics