Title:
ENVELOPE ESTIMATING METHOD OF FREQUENCY DOMAIN CONVERTING COEFFICIENT OF ACOUSTIC SIGNALS
Document Type and Number:
Japanese Patent JP3468335
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To precisely obtain the power envelope of MDCT coefficients.
SOLUTION: The sample series of acoustic signals are superimposed for every N samples and taken out for every 2N samples (12). Then, these samples are multiplied by a Hanning function window (13). Samples x(i), (i=0,..., N/2-1) having an N/2 length of the beginning of a frame are reversed in time and substrated from next N/2 x(i), (i=N/2,..., N-1). Then, x(i), (i=N+N/2,..., 2N-1) having an N/2 length of the end of the frame are reversed in time, added to N/2 x(i), (i=N,..., N+N/2-1) just before, a folded process result y(i) is DCTed and MDCT coefficients are obtained (26). Moreover, y(i) is lenear prediction analyzed (24) and the envelopes of the MDCT coefficients are obtained from the power spectrum envelope of the predicted coefficients (28).
Inventors:
Takehiro Moriya
Akio Jin
Naoki Iwakami
Satoshi Miki
Kazunaga Ikeda
Akio Jin
Naoki Iwakami
Satoshi Miki
Kazunaga Ikeda
Application Number:
JP19037596A
Publication Date:
November 17, 2003
Filing Date:
July 19, 1996
Export Citation:
Assignee:
Nippon Telegraph and Telephone Corporation
International Classes:
G10L19/02; G10L19/04; G10L25/00; G10L25/18; H03M7/30; H04B14/04; (IPC1-7): G10L19/04; G10L11/00; H03M7/30; H04B14/04
Domestic Patent References:
| JP6232824A | ||||
| JP444099A |
Attorney, Agent or Firm:
Suguru Kusano
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