Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
130 words
A speech decoder characterized by comprising: separating means (100) for separating a code string of a filter parameter, a code string of a parameter associated with a pitch, and a code string of a parameter associated with an index and a gain of a codebook representing an excitation signal of speech from a received code string; error correction decoding means (105) for detecting a transmission error, which cannot be corrected, in the received code string; interpolating means (110) for, when a transmission error which cannot be corrected is detected, interpolating between parameters of past and future proper frames, thereby recovering parameters of a current frame; and speech reproducing means (120, 130, 135, 165, 170) for reproducing a speech signal on the basis of the interpolated parameters and other received codes.
Claim 2
Dependent Claim
33 words
A decoder according to claim 1, wherein said error correction decoding means (105) performs error correction of a parameter to which an error correction code is added, and subsequently outputs a code string.
Claim 3
Dependent Claim
29 words
A decoder according to claim 1 or 2, wherein said error correction decoding means (105) detects a transmission error which cannot be corrected by using an error detection code.
Claim 4
Dependent Claim
49 words
A decoder according to claim 1, 2,or 3, further comprising weighting means (175) for, when a transmission error which cannot be corrected is detected in a received code string, weighting a filter parameter in a predetermined number of frames starting from a frame in which the error is detected.
Claim 5
Dependent Claim
40 words
A decoder according to claim 1, 2, or 3, further comprising weighting means (175) for, when a transmission error which cannot be corrected is detected in a received code string, weighting a filter parameter until a predetermined condition is satisfied.
Claim 6
Dependent Claim
72 words
A decoder according to any one of claims 1 to 5, further comprising gain control means (168) for, when a transmission error which cannot be corrected is detected in a received code string, and a value of a reproduced signal exceeds a predetermined threshold value, controlling a gain of an excitation signal or the reproduced signal in a predetermined number of frames starting from a frame in which the error is detected.
Claim 7
Dependent Claim
62 words
A decoder according to any one of claims 1 to 6, further comprising gain control means (168) for, when a transmission error which cannot be corrected is detected in a received code string, and a value of a reproduced signal exceeds a predetermined threshold value, controlling a gain of an excitation signal or the reproduced signal until a predetermined condition is satisfied.