Method and apparatus to evaluate audio equipment via filter banks

摘要

A testing method or apparatus utilizes filter banks to measure time varying or dynamic harmonic distortion or intermodulation distortion. With a stairstep signal and filter banks, Nth order harmonic and or intermodulation distortion is measured via the filter banks at different offsets provided by an arbitrary low frequency signal. An amplifier with crossover distortion will show increased harmonic and or intermodulation distortion near the zero crossing while providing less distortion in other portions of the transfer curve of the amplifier.

主权项

1. Method for measuring in a time domain, time varying harmonic distortion from an audio device, wherein the audio device has an input and an output, comprising:
providing a first signal comprising a pulsed, sinusoidal, stairstep, staircase, bipolar, and or arbitrary waveform and a second signal whose frequency is higher than the frequency of the first signal, to an input of the audio device; coupling the output of the audio device to an input of a filter bank, and wherein the filter bank includes, at least one output terminal; measuring the time varying harmonic distortion via measuring or displaying the amplitude level from one of the output terminals of the filter bank to provide the time varying harmonic distortion measurement of the audio device, wherein the time varying harmonic distortion includes a harmonic distortion signal of the second signal, and wherein the harmonic distortion signal of the second signal is varied or induced by the first signal.