SIGNAL ANALYSIS METHOD

摘要

By paying attention on a harmonic spectrum characteristic on a logarithmic frequency axis, it is possible to visually present the basic frequency appearance by performing a predetermined conversion operation. When each of the sounds constituting a multiplexed sound has a spectrum of a common harmonic structure pattern, on the logarithmic frequency axis, they are in the relationship obtained by parallel-displacing the same overtone pattern shape. This can be interpreted to be convolution of the distribution of the reference frequency of the multiplexed sound and the common harmonic structure pattern on the logarithmic frequency axis. It can be considered that the basic frequency distribution is the input while the common harmonic structure patter is a linear output as the impulse response. By assuming a common harmonic structure pattern and performing counter convolution by using division in the Fourier region for the logarithmic frequency region, it is possible to calculate the basic frequency as a continuous distribution. By displaying the result in dark/light coloring or in multiple colors, it is possible to obtain a basic frequency distribution display similar to a spectrogram.