The harmonic distortion level measurement system of the loudspeaker using two adaptive filters
Toyota Fujioka, Yoshifumi Nagata, Masato Abé · The Journal of the Acoustical Society of America · 2012
The harmonic distortion level is an important criterion to evaluate loudspeaker performance. The harmonic distortion level is generally obtained using the power spectrum of the audio signal from a loudspeaker, and a microphone is used to receive the audio signal. It is important to measure the accurate harmonic distortion level for evaluating performance of the loudspeaker. Generally, The harmonic distortion level is measured by the spectrum analysis. However, the spectrum analysis requires large computational complexity. Therefore, we proposed the new technique to measure the harmonic distortion level of the loudspeaker by using the adaptive filter. And we evaluated the performance of the proposed technique by experiment. The proposed technique can measure the accurate level the same as the spectrum analysis, but requires long measurement time to converge the filter coefficient. This paper presents a description of the new technique to measure the harmonic distortion of the loudspeaker by using two adaptive filters. The propose technique improves the accuracy and the measurement time of the proposed measurement technique by using the adaptive filter. We show some results of real-time experiments. The results of the real-time experiments verified that the newly proposed technique improves measurement time and accuracy of measured level.