Nonlinear Distortion Meter

an instrument used to measure nonlinear distortions of signals in radio-engineering equipment (such as amplifiers of electrical oscillations, radio receiving and transmitting devices, and sound recording equipment). Nonlinear distortions are evaluated according to the nonlinear harmonic distortion coefficient:

where U₁ is the voltage of the fundamental frequency (first harmonic) and U_n...,U₂ are the effective voltages of the higher

harmonic components of the signal being studied, starting with the second harmonic. Nonlinear distortion meters operate with a smooth frequency overlap in the range from 5 hertz to 3 megahertz, and also at fixed frequencies in the same range; the level of signals being studied is 0.1 to 300 watts; measurement limits for Kf are 0.1 to 100 percent; and measurement error is 3–5 percent.