EP0338040A1 - Procede de transmission de signaux audio - Google Patents

Procede de transmission de signaux audio

Info

Publication number
EP0338040A1
EP0338040A1 EP88908217A EP88908217A EP0338040A1 EP 0338040 A1 EP0338040 A1 EP 0338040A1 EP 88908217 A EP88908217 A EP 88908217A EP 88908217 A EP88908217 A EP 88908217A EP 0338040 A1 EP0338040 A1 EP 0338040A1
Authority
EP
European Patent Office
Prior art keywords
bits
amounts
distributed
values
spectrum
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP88908217A
Other languages
German (de)
English (en)
Inventor
Walter VÖSSING
Ronald Hein
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Deutsche Thomson Brandt GmbH
Original Assignee
Deutsche Thomson Brandt GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Deutsche Thomson Brandt GmbH filed Critical Deutsche Thomson Brandt GmbH
Publication of EP0338040A1 publication Critical patent/EP0338040A1/fr
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/66—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for reducing bandwidth of signals; for improving efficiency of transmission
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/66—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for reducing bandwidth of signals; for improving efficiency of transmission
    • H04B1/665—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for reducing bandwidth of signals; for improving efficiency of transmission using psychoacoustic properties of the ear, e.g. masking effect
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits

Definitions

  • the invention relates to a method for transmitting an audio signal according to the preamble of claim 1.
  • an audio signal When transmitting an audio signal, e.g. In radio broadcasting, cable transmission, satellite transmission and in recording devices, it is known to convert the analog audio signal into a digital audio signal with a certain resolution, to transmit it in this form and to convert it back into an analog signal during playback.
  • the digital transmission achieves a greater signal-to-noise ratio, particularly during playback.
  • the bandwidth required for the transmission of such a signal is essentially determined by the number of samples to be transmitted per unit of time and by the resolution.
  • the digital audio signal is transformed in successive sections into a short-term spectrum which represents the spectral components of the signal for each time period, for example 20 ms.
  • a short-term spectrum which represents the spectral components of the signal for each time period, for example 20 ms.
  • components that are not perceived by the listener can generally be nical meaning are irrelevant, easier to find than in the time domain.
  • These components are weighted less during transmission or left out entirely.
  • This measure means that a considerable part of the otherwise necessary data can be omitted during the transmission, so that the average bit rate can be considerably reduced. Therefore, only a limited number of bits is provided for coding the spectral components present in the time segments, namely the amounts and phases, which is predetermined by the desired data reduction.
  • the object of the invention is to assign the bits available for coding to the spectral components to be transmitted in the method described in the introduction in such a way that a quantization corresponding to the weighting of the spectral components with as complete a utilization of the available bits as possible within can be realized in a short time.
  • the first step is to assign a predetermined number of bits to the absolute maximum, the maximum in frequency groups of the short-term spectrum, the addresses of the maximum and the dynamics of the frequency groups. From the dynamics of the groups, quantization indicators are len and assigned to the remaining amounts in accordance with the quantization indicators bit. The phases are quantized with the same number of bits.
  • the assignment of the bits on the basis of the quantization indicators represents a rough quantization. It is dimensioned such that even in the case of short-term spectra with many amount and phase values to be transmitted, the number of bits available for coding is sufficient for an initial assignment.
  • a control variable is then defined which controls the distribution of the remaining bits over selected spectral components. It is placed as a threshold in the range of magnitudes, the height of the threshold depending on the number of bits not distributed during the rough quantization.
  • bits can only be distributed in whole numbers, there remains a remaining number of bits that is still available for distribution. These bits can either be disregarded, or can be distributed by rounding up and down and corresponding to the absolute amounts of the magnitude values of the spectrum.
  • FIG. 1 shows a block of an audio signal transformed into the frequency range in an amount
  • FIG. 2 shows a modified spectrum.
  • the signal shown in FIG. 1 is obtained by converting a low-pass filtered audio signal into a digital signal by means of an analog / digital converter, cutting out a specific section of the digital audio signal from the long-term signal through a time window and the block thus obtained from the time domain is transformed into the frequency range.
  • a number I of spectral lines occurring within a transformed block are plotted in relation to an O-dB line. These are the amounts B.
  • a control variable St which results from the number of non-distributed bits, is shown as a horizontal line. It is determined according to the empirical formula:
  • the spectral lines end partly above, partly below the control variable St.
  • the amounts B below the control variable are not assigned any bits. Forming the difference between the amounts B above the control variable St and the control variable St itself results in a modified spectrum, which is shown in FIG. 2.
  • the control variable St is compared with the amounts B. Only those amounts B that are above the control variable B are taken into account. The result is shown in FIG. 2.
  • the amounts B of this modified spectrum are summed. The values B are added up according to the formula:
  • bits can only be distributed in whole numbers, there remains a remaining number that is still available for distribution. These bits are distributed by rounding and transferring the remainder in accordance with the absolute amounts of the magnitude values of the spectrum.
  • the procedure is as follows: the first number of bits to be distributed is first rounded off and the rest is buffered between the non-integer and the integer number of bits. The temporarily stored remainder is then added to the next number of bits to be distributed. The sum thus obtained is rounded off again and the rest is stored again. The rest is added to the next number of bits to be distributed. These cycles are repeated for each amount to be quantized until the last number of bits to be distributed is distributed. Since the value "one" is reached with great probability after the addition of several residues, a further bit can be distributed repeatedly after several cycles, so that finally only one or no bit remains.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Compression, Expansion, Code Conversion, And Decoders (AREA)
  • Devices For Supply Of Signal Current (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
  • Analogue/Digital Conversion (AREA)
  • Reduction Or Emphasis Of Bandwidth Of Signals (AREA)

Abstract

Lors du codage par transformation de signaux audio, des bits sont attribués aux composants spectraux afin de les quantifier. Après une quantification approximative préliminaire, il faut résoudre le problème qui consiste à répartir de telle sorte les bits encore disponibles dans un bloc de données parmi les composants spectraux que l'on obtienne une précision aussi élevée que possible. On procède à la quantification précise selon les étapes suivantes: a) détermination des valeurs en tant que valeurs absolues, b) conversion de la norme des valeurs par une valeur de commande, c) totalisation de toutes les valeurs supérieures à 0, d) détermination d'une valeur de commande à partir des bits épargnés et de la somme effectuée auparavant, e) attribution des bits restants aux valeurs, compte tenu des valeurs caractéristiques. On peut appliquer l'invention dans des systèmes audio avec lesquels on cherche d'obtenir une transmission de haute qualité à une vitesse réduite de données.
EP88908217A 1987-09-30 1988-09-27 Procede de transmission de signaux audio Pending EP0338040A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3733016 1987-09-30
DE3733016 1987-09-30

Publications (1)

Publication Number Publication Date
EP0338040A1 true EP0338040A1 (fr) 1989-10-25

Family

ID=6337280

Family Applications (2)

Application Number Title Priority Date Filing Date
EP88115850A Expired - Lifetime EP0309974B1 (fr) 1987-09-30 1988-09-27 Procédé pour transmettre un signal audible
EP88908217A Pending EP0338040A1 (fr) 1987-09-30 1988-09-27 Procede de transmission de signaux audio

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP88115850A Expired - Lifetime EP0309974B1 (fr) 1987-09-30 1988-09-27 Procédé pour transmettre un signal audible

Country Status (8)

Country Link
EP (2) EP0309974B1 (fr)
JP (1) JP2839521B2 (fr)
KR (1) KR890702346A (fr)
AT (1) ATE73591T1 (fr)
DE (1) DE3869034D1 (fr)
ES (1) ES2030814T3 (fr)
GR (1) GR3004915T3 (fr)
WO (1) WO1989003140A1 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU7041791A (en) * 1989-10-06 1991-04-28 Telefunken Fernseh Und Rundfunk Gmbh Process for transmitting a signal
FR2653280B1 (fr) * 1989-10-13 1992-01-10 France Etat Dispositif d'allocation de bits pour signal audio-numerique transforme, a quantification adaptative sur critere psycho-auditif.
CA2105387A1 (fr) * 1991-03-05 1992-09-06 Antony H. Crossman Codeur de paroles a debit binaire variable
JP3186290B2 (ja) * 1993-01-20 2001-07-11 ソニー株式会社 符号化方法、符号化装置、復号化装置及び記録媒体
JP4789317B2 (ja) * 2000-10-13 2011-10-12 オリンパス株式会社 内視鏡装置
EP1318611A1 (fr) * 2001-12-06 2003-06-11 Deutsche Thomson-Brandt Gmbh Procédé pour récupérer une critère sensible pour détéction de spectre quantifier

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE430739B (sv) * 1982-04-27 1983-12-05 Tore Torstensson Fjellbrant Anordning for omvandling, overforing och ateromvandling av en samplad signal
DE3506912A1 (de) * 1985-02-27 1986-08-28 Telefunken Fernseh Und Rundfunk Gmbh, 3000 Hannover Verfahren zur uebertragung eines audiosignals

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8903140A1 *

Also Published As

Publication number Publication date
EP0309974A1 (fr) 1989-04-05
DE3869034D1 (de) 1992-04-16
JP2839521B2 (ja) 1998-12-16
WO1989003140A1 (fr) 1989-04-06
ES2030814T3 (es) 1992-11-16
JPH02501435A (ja) 1990-05-17
EP0309974B1 (fr) 1992-03-11
GR3004915T3 (fr) 1993-04-28
ATE73591T1 (de) 1992-03-15
KR890702346A (ko) 1989-12-23

Similar Documents

Publication Publication Date Title
EP0193143B1 (fr) Procédé de transmission d'un signal audio
DE3784120T2 (de) Tabellengesteuerte dynamische bitverteilung in einem teilband-sprachkodierer mit veraenderlicher datenrate.
DE2818052C2 (de) Quantisierung eines Signals mit einem sich über ein gegebenes Frequenzband erstreckendem Spetkrum
DE69219718T2 (de) Digitales Datenkodierungs-und Dekodierungsgerät mit hoher Wirksamkeit
DE69320722T2 (de) Quantisierungsbitzahlzuweisung dadurch, dass zuerst das Subband mit der höchsten Signal/Verdeckungsrate ausgewählt wird
DE69225100T2 (de) Reduzierung der Zusaztinformation bei Teilbandkodierungsverfahren
EP0277613B1 (fr) Procédé de transmission de signal audio
EP0910927B1 (fr) Procede de codage et de decodage de valeurs spectrales stereophoniques
DE60307252T2 (de) Einrichtungen, verfahren und programme zur kodierung und dekodierung
DE2124754C3 (de) Verfahren und Vorrichtung zur differentiellen Pulscodemodulation
DE69106580T2 (de) Codieranordnung mit einem Unterbandcoder und Sender mit der Codieranordnung.
WO1990009063A1 (fr) Procede de transmission de signaux
WO1993008656A1 (fr) Procede de transmission ou de memorisation d'un signal audio code numerise compose d'une sequence de blocs d'informations, par des canaux brouilles
DE69107511T2 (de) Codierverfahren und Codieranordnung mit einem Unterbandcoder und Sender mit der Codieranordnung.
EP0494918B1 (fr) Procede pour la transmission d'un signal
EP0485390B1 (fr) Procede pour transmettre un signal
WO1989003140A1 (fr) Procede de transmission de signaux audio
EP0635177B1 (fr) Procede de transmission ou de stockage de signaux audio numerisesa donnees reduites
WO1990014717A1 (fr) Convertisseur numerique-analogique a haute linearite
EP0027233B1 (fr) Procédé de codage de signaux analogiques
DE19625855A1 (de) Verfahren und Signalauswerteeinrichtung zur Datenreduktion bei der Verarbeitung von Signalwerten mit einer digitalen Signalverarbeitungseinheit in einem Übertragungssystem
EP0610282B1 (fr) Procede de transmission simultanee de signaux audio en provenance de n sources de signaux
DE2319650A1 (de) Verfahren und anordnung zum umwandeln eines nachrichtensignals aus einem digitalen codeformat in ein anderes
WO1989003574A1 (fr) Procede de codage numerique adaptatif par transformees
EP0133697B1 (fr) Procédé de transmission de signaux sonores numériques ainsi que dispositif de réception d'un signal sonore transmis d'après ce procédé

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 19890513

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

XX Miscellaneous (additional remarks)

Free format text: VERFAHREN ABGESCHLOSSEN INFOLGE VERBINDUNG MIT 88115850.5/0309974 (EUROPAEISCHE ANMELDENUMMER/VEROEFFENTLICHUNGSNUMMER) VOM 26.06.91.