Voice recording-reproducing system and voice recording-reproducing method using the same

• US 6,778,956 B1
• Filed: 10/16/2000
• Issued: 08/17/2004
• Est. Priority Date: 03/02/2000
• Status: Active Grant

• Current Assignee: Rakuten Group, Inc.
• Original Assignee: OKI Electric Industry Company Limited
• Inventors: Sasaki, Hiroshi, Sato, Masayasu
• Primary Examiner(s): CHAWAN, VIJAY B
• Application Number:
  US09/688,139
• Time in Patent Office: 1,401 Days
• Field of Search: 704/200, 704/201, 704/260, 704/212, 704/230, 704/229, 704/219
• US Class Current: 704/230
• CPC Class Codes: G10L 19/08 Determination or coding of the excitation function; Determination or coding of the long-term prediction parameters

Abstract

Code patterns are first sorted in a codebook in order of power, and catalogued while preparing fixed parameters indicating a selection range size of the code patterns (not greater than values recordable in an analog flash memory), and a variable parameter indicating an offset amount of a selection range, from the leading edge of the codebook. When selecting a waveform, such selection is made from among the code patterns within the selection range, and the selection range is shifted to the optimal position by sequentially renewing the offset amount on the basis of a code number resulting from encoding of a preceding frame, and is then decided upon.

Claims

1. A voice recording-reproducing system comprising:

means of sampling voice signals on the basis of a preset sampling frequency;

frame waveform storage means of storing a plurality of sample data in succession as one frame waveform;

codebook storage means of storing a codebook for sorting standard patterns of the frame waveforms in order of power, and cataloging sets of the standard pattern as sorted and a pattern number, a selection range size for selecting a frame waveform from the codebook, and an offset amount of a selection range, from the leading edge of the codebook;

waveform selection means of selecting a code pattern most similar to an input frame waveform among code patterns cataloged in the codebook storage means;

means of converting a code number corresponding to the code pattern selected by the waveform selection means into an analog value, and recording the analog value in an analog flash memory; and

code pattern selection range alteration means of renewing the offset amount of the selection range, on the basis of a code number resulting from encoding of a preceding frame.

2. A voice recording-reproducing method for recording voice, comprising the steps of:

(a) storing a codebook for sorting standard patterns of frame waveforms in order of power, and cataloging sets of the standard pattern as sorted and a pattern number, a selection range size for selecting a frame waveform from the codebook, and an offset amount of a selection range, from the leading edge of the codebook;

(b) sampling voice signals on the basis of a preset sampling frequency;

(c) creating one frame waveform from a plurality of sample data in succession;

(d) selecting a code pattern most similar to an input frame waveform from among a plurality of code patterns within a code pattern selection range of the codebook, and acquiring a code number allocated to the code pattern;

(e) converting the code number into an analog value, and recording the analog value in an analog flash memory;

(f) renewing the offset amount of the selection range on the basis of a code number resulting from encoding of a preceding frame; and

(g) repeating processing by the above-described steps from (b) to (f) until input voice signals come to an end.

3. A voice recording-reproducing method for recording voice according to claim 2, wherein the step (f) of altering the code pattern selection range comprises the following sub-steps of:

(a) acquiring the offset amount B indicating a starting position of the code pattern selection range;

(b) substituting (B+1)+k−

W/2 for the offset amount B provided that the code number corresponding to a frame waveform of the preceding frame is k, and a predetermined size of the selection range is W; and

(c) altering a code pattern selection range for a succeeding frame to [B+1, B+W].

4. A voice recording-reproducing system comprising:

means of sampling voice signals on the basis of a preset sampling frequency;

frame waveform storage means of storing a plurality of sample data in succession as one frame waveform;

codebook storage means of storing a plurality of codebooks cataloging standard patterns of the frame waveforms, sorted in increasing order of average power of cataloged patterns, a codebook number in current use, and switchover condition parameters for a codebook in current use;

waveform selection means of selecting a code pattern most similar to an input frame waveform from among code patterns cataloged in the codebook storage means;

means of converting a code number corresponding to the code pattern selected by the waveform selection means into an analog value, and recording the analog value in an analog flash memory; and

code pattern selection range alteration means of renewing the codebook number through comparison of a code number resulting from encoding of a preceding frame with the switchover condition parameters for the codebook in current use.

5. A voice recording-reproducing method for recording voice, comprising the steps of:

(a) storing a plurality of codebooks cataloging standard patterns of frame waveforms, sorted in increasing order of average power of cataloged patterns, a codebook number in current use, and switchover condition parameters for a codebook in current use;

(b) sampling voice signals on the basis of a preset sampling frequency;

(c) creating one frame waveform from a plurality of sample data in succession;

(d) selecting a code pattern most similar to an input frame waveform among code patterns cataloged in the respective codebooks, and acquiring a code number allocated to the code pattern;

(e) converting the code number into an analog value, and recording the analog value in an analog flash memory;

(f) renewing the codebook number through comparison of a code number resulting from encoding of a preceding frame with the switchover condition parameters for the codebook in current use; and

(g) repeating processing by the above-described steps from (b) to (f) until input voice signals come to an end.

6. A voice recording-reproducing method for recording voice according to claim 5, wherein the step (f) of renewing the codebook number, comprises the following sub-steps of:

(a) acquiring the switchover condition parameters for the codebook in current use, comprised of the codebook number “

N”

in current use, an upward switchover number “

U”

, and a downward switchover number “

L”

;

(b) comparing the code number k of the preceding frame with “

L”

, and subtracting 1 from “

N”

if k≦

L while comparing k with “

U”

if k>

L; and

(c) adding 1 to “

N”

if k≧

U upon comparing k with “

U”

, and keeping the value “

N”

unaltered if k<

U.