(19)
(11) EP 0 725 384 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
27.12.1996 Bulletin 1996/52

(43) Date of publication A2:
07.08.1996 Bulletin 1996/32

(21) Application number: 96200973.4

(22) Date of filing: 25.05.1989
(51) International Patent Classification (IPC)6: G10L 7/06
(84) Designated Contracting States:
AT BE CH DE FR GB IT LI LU NL SE

(30) Priority: 26.05.1988 US 199360

(62) Application number of the earlier application in accordance with Art. 76 EPC:
89907458.7 / 0416036

(71) Applicant: PACIFIC COMMUNICATION SCIENCES, INC.
San Diego, California 92121-1761 (US)

(72) Inventor:
  • Wilson, Philip J.
    San Diego, California 92130 (US)

(74) Representative: W.P. THOMPSON & CO. 
Eastcheap House Central Approach
Letchworth, Hertfordshire SG6 3DS
Letchworth, Hertfordshire SG6 3DS (GB)

 
Remarks:
This application was filed on 09 - 04 - 1996 as a divisional application to the application mentioned under INID code 62.
 


(54) Adaptive transform coding


(57) Determining formant information of a speech signal in a transform coder in order to reduce noise and distortion caused by quantization is disclosed. Dividing the signal into blocks using a window (52) is followed by dynamic scaling (54) used to conserve necessary processing for the discrete cosine transform (64) and the use of LPC coefficients (68) for pitch generation (82) and bit allocation (108). Consequently, the transformed information (64), pitch (106), and bit allocation (108) are utilized for accurate quantization (66) of the speech signal. Dynamic scaling (54), pitch (97), and quanitization (66 and 80) information are then converted to a standard format (116) for transmission and subsequent decoding.






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