Signal processing method and sound source data forming apparatus
US5430241A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 16, 1989 |
| Grant date | Jul 4, 1995 |
| Priority date | — |
| Expiry date | Nov 16, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S84/09
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A method for processing a digital signal produced by digitizing an analog signal such as a musical instrument sound signal, and an apparatus for producing sound source data. When the input signal contains a periodically repetitive waveform portion, the fundamental frequency and its high harmonic components of the input signal is extracted by a comb filter prior to signal processing which takes advantage of the periodicity of the input signal. The fundamental frequency or pitch is detected by performing Fourier transform to produce frequency components, phase matching these frequency components and performing inverse Fourier transform. When extracting a repetitive waveform portion or so-called looping domain, such looping domain having the highest similarity in waveform in the vicinity of both ends of the domain is selected. When the bit compression of digital signal data is performed by selecting a filter with blocks each consisting of plural samples as units, a pseudo signal is affixed to the input signal, before the start point of the input signal, which pseudo signal will cause a filter of the lowest order to be selected. The looping domain is set so as to be a whole number mult…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.