DEVICE AND METHOD FOR MEASURING DISTORTION OF AUDIO SIGNAL

PURPOSE: To objectively evaluate the performance capable of quantitatively determining the distortion degree to a wide band audio signal by extracting a masking threshold which is acoustic characteristic to the power spectrum of an input signal. CONSTITUTION: A signal power spectrum evaluating device 20 windows an input signal X(n) followed by discrete Fourier transform, and finds and outputs a power density spectrum X(k) to N-pieces of audio signals. A masking threshold detecting device 30 extracts the optimum masking threshold LTg(i) reflecting the acoustic characteristic of person. An error power spectrum evaluating device 40 outputs an error signal power density spectrum E(k) to an error signal e(n) which is the difference between the input signal X(n) and the output signal Y(n) through an audio signal processing system. A distortion value evaluating device 50 inputs the optimized threshold LTg(i) and the power density spectrum E(k) to determine a distortion curve PSD.