Title:
【発明の名称】雑音削減装置
Document Type and Number:
Japanese Patent JP3204501
Kind Code:
B2
Abstract:
PCT No. PCT/GB89/00049 Sec. 371 Date Sep. 15, 1989 Sec. 102(e) Date Sep. 15, 1989 PCT Filed Jan. 18, 1989 PCT Pub. No. WO89/06877 PCT Pub. Date Jul. 27, 1989.A noise reduction system for enhancing noisy speech signals by performing a spectral decomposition on the signal, passing each spectral component through a non-linear stage which progressively attenuates lower intensity spectral components (uncorrelated noise) but passes higher intensity spectral components (correlated speech) relatively unattenuated, and reconstituting the signal. Frames of noisy signal are transformed into the frequency domain by an FFT (Fast-Fourier Transform) device, with windowing. Each transformed frame is then processed to effect a non-linear transfer characteristic, which is linear above a soft "knee" region, and rolls off below, and transformed back to a reconstituted time-domain signal with reduced noise by an IFFT (Inverse Fast Fourier Transform) device (with overlapping). A level control matches the signal to the characteristic. In further embodiments, the characteristic may vary between frequency bands, and may be matched to speech formants by tracking formants using an LSP (Linear Spectral Pairs) technique.
Inventors:
Monday Edward
Application Number:
JP50154289A
Publication Date:
September 04, 2001
Filing Date:
January 18, 1989
Export Citation:
Assignee:
British Telecommunications Public Limited Company
International Classes:
G10L21/0208; H03G7/00; H03H17/02; G10L21/0232; (IPC1-7): H03G7/00; H03H17/02
Domestic Patent References:
| JP631111A | ||||
| JP63191420A |
Other References:
【文献】米国特許4221934(US,A)
【文献】米国特許4544916(US,A)
【文献】米国特許4544916(US,A)
Attorney, Agent or Firm:
Naotaka Ide