| US 7,577,567 B2 | ||
| Multimode speech coding apparatus and decoding apparatus | ||
| Hiroyuki Ehara, Yokohama (Japan) | ||
| Assigned to Panasonic Corporation, Osaka (Japan) | ||
| Filed on Dec. 12, 2006, as Appl. No. 11/637,128. | ||
| Application 11/637128 is a continuation of application No. 09/914916, filed on Sep. 06, 2001, granted, now 7,167,828. | ||
| Prior Publication US 2007/0088543 A1, Apr. 19, 2007 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. G10L 19/12 (2006.01) | ||
| U.S. Cl. 704—223 [704/219; 704/222; 704/228; 704/220; 704/230] | 6 Claims |
| 1. A speech decoding apparatus comprising:
a decoder that decodes a code representing a quantized LPC and generates a decoded LSP parameter for a current frame;
a mode determining apparatus that calculates an average decoded LSP parameter in a period in which a decoded LSP parameter
is stationary and determines whether the current frame indicates a speech mode or non-speech mode utilizing the average decoded
LSP parameter; and
a stationary noise generator that drives a synthesis filter with a random signal obtained from a random codebook, the synthesis
filter comprising an LPC parameter obtained from the average decoded LSP parameter calculated in a period other than a period
in which the mode determining apparatus determined to indicate the speech mode, and generates a stationary noise signal and
superimposes the stationary noise signal over a decoded speech signal.
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