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1. (WO1997030525) REDUCED COMPLEXITY SIGNAL TRANSMISSION SYSTEM
Latest bibliographic data on file with the International Bureau   

Pub. No.: WO/1997/030525 International Application No.: PCT/IB1997/000069
Publication Date: 21.08.1997 International Filing Date: 31.01.1997
IPC:
G10L 19/12 (2013.01) ,H03M 7/30 (2006.01) ,H04B 1/62 (2006.01)
G PHYSICS
10
MUSICAL INSTRUMENTS; ACOUSTICS
L
SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
19
Speech or audio signal analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis
04
using predictive techniques
08
Determination or coding of the excitation function; Determination or coding of the long-term prediction parameters
12
the excitation function being a code excitation, e.g. in code excited linear prediction [CELP] vocoders
H ELECTRICITY
03
BASIC ELECTRONIC CIRCUITRY
M
CODING, DECODING OR CODE CONVERSION, IN GENERAL
7
Conversion of a code where information is represented by a given sequence or number of digits to a code where the same information is represented by a different sequence or number of digits
30
Compression; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
H ELECTRICITY
04
ELECTRIC COMMUNICATION TECHNIQUE
B
TRANSMISSION
1
Details of transmission systems, not covered by a single one of groups H04B3/-H04B13/123; Details of transmission systems not characterised by the medium used for transmission
62
for providing a predistortion of the signal in the transmitter and corresponding correction in the receiver, e.g. for improving the signal/noise ratio
Applicants:
PHILIPS ELECTRONICS N.V. [NL/NL]; Groenewoudseweg 1 NL-5621 BA Eindhoven, NL
PHILIPS NORDEN AB [SE/SE]; Kottbygatan 7 Kista S-164 85 Stockholm, SE (SE)
Inventors:
WUPPERMANN, Friedhelm; NL
DE BONT, Fransiscus, Marinus, Jozephus; NL
Agent:
DEGUELLE, Wilhelmus, H., G.; Internationaal Octrooibureau B.V. P.O. Box 220 NL-5600 AE Eindhoven, NL
Priority Data:
96200371.115.02.1996EP
Title (EN) REDUCED COMPLEXITY SIGNAL TRANSMISSION SYSTEM
(FR) SYSTEME DE TRANSMISSION DE SIGNAUX A COMPLEXITE REDUITE
Abstract:
(EN) In a CELP coder a comparison between a target signal and a plurality of synthetic signals is made. The synthetic signal is derived by filtering a plurality of excitation sequences by a synthesis filter having parameters derived from the target signal. The excitation signal which results in a minimum error between the target signal and the synthetic signal is selected. The search for the best excitation signal requires a substantial computational complexity. To reduce the complexity a preselection of a small number of excitation sequences is made by selecting a small number of excitation sequences resembling the most a backward filtered target signal. With this small number of excitation sequences a full complexity search is made. Due to the reduced number of excitation sequences involved in the final selection the required computational complexity is reduced.
(FR) On effectue, dans un codeur CELP, une comparaison entre un signal cible et plusieurs signaux de synthèse. On dérive le signal de synthèse en filtrant plusieurs séquences d'excitation à l'aide d'un filtre de synthèse possédant des paramètres dérivés du signal cible. On sélectionne le signal d'excitation donnant une valeur d'erreur minimale entre le signal cible et le signal de synthèse. La recherche du meilleur signal d'excitation exige des calculs très complexes. Afin de réduire cette complexité, on effectue une présélection d'un petit nombre de séquences d'excitation en choisissant un petit nombre de séquences d'excitation s'approchant le plus d'un signal cible ayant été soumis à un filtrage inverse. On effectue, en s'aidant de ce petit nombre de séquences d'excitation, une recherche d'une totale complexité. Du fait du nombre réduit de séquences d'excitation participant à la sélection définitive, le volume des calculs fort complexe que réclame ce type d'opération est réduit.
Designated States: CA, CN, JP, KR
European Patent Office (EPO) (AT, BE, CH, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE)
Publication Language: English (EN)
Filing Language: English (EN)