Subband coded digital transmission system using some composite signals

• US 5,606,618 A
• Filed: 12/27/1993
• Issued: 02/25/1997
• Est. Priority Date: 06/02/1989
• Status: Expired due to Term

• Current Assignee: TDF SAS (Fluor Corporation), Institut Fur Rundfunktechnik GmbH, US Philips Corporation (Koninklijke Philips N.V.), Telediffusion De France SA
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Dehery, Y. F., Theile, G., Stoll, G., Lokhoff, Gerardus C. P.
• Primary Examiner(s): Isen, Forester W.
• Application Number:
  US08/173,850
• Time in Patent Office: 1,156 Days
• Field of Search: 381/22, 381/23, 381/1, 381/2, 395/2.12, 395/2.14, 395/2.38
• US Class Current: 381/2
• CPC Class Codes: G10L 19/008 Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
• CPC Class Codes: G10L 19/0208 Subband vocoders
• CPC Class Codes: G11B 20/00007 Time or data compression or expansion audio compression based on psychoacoustics G10L19/00; data processing for reproducing audio data at different playback speeds G10L21/04; video compression H04N19/00; data compression per se H03M7/30
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00992 Circuits for stereophonic or quadraphonic recording or reproducing
• CPC Class Codes: G11B 20/10 Digital recording or reproducing
• CPC Class Codes: G11B 20/10527 Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: G11B 20/12 Formatting, e.g. arrangement of data block or words on the record carriers within interface between computers and data recorders G06F3/06
• CPC Class Codes: G11B 20/1833 by adding special lists or symbols to the coded information G11B20/1806, G11B20/1866 take precedence
• CPC Class Codes: G11B 2020/10592 specifically adapted for recording or reproducing multichannel signals
• CPC Class Codes: G11B 2020/10601 surround sound signal
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• CPC Class Codes: G11B 2220/913 Digital audio tape [DAT] format
• CPC Class Codes: G11B 2220/93 Longitudinal format, wherein tracks are in the direction of the tape, read with a static head, e.g. DCC
• CPC Class Codes: G11B 27/3027 used signal is digitally coded
• CPC Class Codes: H04B 1/665 using psychoacoustic properties of the ear, e.g. masking effect
• CPC Class Codes: H04B 1/667 using a division in frequency subbands for TV signals H04N19/63
• CPC Class Codes: H04H 20/28 Arrangements for simultaneous broadcast of plural pieces of information
• CPC Class Codes: H04H 20/30 by a single channel
• CPC Class Codes: H04H 20/31 using in-band signals, e.g. subsonic or cue signal
• CPC Class Codes: H04H 20/47 : specially adapted for stereophonic broadcast systems
• CPC Class Codes: H04H 20/88 : Stereophonic broadcast systems multiplex system in general H04J
• CPC Class Codes: H04H 20/89 : using three or more audio channels, e.g. triphonic or quadraphonic
• CPC Class Codes: H04H 20/95 : characterised by a specific format, e.g. an encoded audio stream
• CPC Class Codes: H04H 40/18 : Arrangements characterised by circuits or components specially adapted for receiving
• CPC Class Codes: H04H 40/36 : specially adapted for stereophonic broadcast receiving
• CPC Class Codes: H04H 60/07 : characterised by processes or methods for the generation
• CPC Class Codes: H04H 60/13 : Arrangements for device control affected by the broadcast information
• CPC Class Codes: H04H 60/18 : on copying information

Abstract

Reproduction accuracy of, for example a digital stereo audio signal, is improved by transmitting sample data as sub-signals such as frequency subband signals. In one or more subbands, corresponding components such as left and right stereo channels are combined so that only one composite signal is transmitted per subband. An indicator signal is transmitted, indicating which subbands are combined. Scale factor signals for all subbands, and for the relative intensity of the respective subband signals which were combined, may also be transmitted. In the receiver a subband signal is derived for each channel from the composite signal, before synthesis of the full channel signals which will be reproduced.

Claims

1. An encoder for encoding a plurality of input signals, comprising

steering means responsive to said plurality of input signals for generating at least one individual signal and a composite signal, said composite signal having a frequency spectrum in one frequency band, and said at least one individual signal having at least one respective frequency spectrum in a plurality of frequency bands excluding said one frequency band, said plurality of frequency bands respectively representing a corresponding one of said plurality of input signals within the plurality of frequency bands, and

control means responsive to said steering means for generating a steering control signal having at least one component relating to said frequency band of said composite signal.

2. An encoder as claimed in claim 1, wherein bandwidths of said frequency bands are respectively approximately equal to the bandwidths of the critical bands of the human ear.

3. An encoder as claimed in claim 1, wherein said plurality of input signals represent input channels, and the steering control signal includes a control signal which represents a ratio of levels between the signals representing the channels, corresponding to the composite signal.

4. An encoder for encoding a plurality of input signals, comprising

steering means responsive to said plurality of input signals for generating at least one individual signal and a composite signal, said at least one individual signal having at least one respective individual frequency spectrum in a first plurality of frequency bands respectively representing a corresponding one of said plurality of input signals within the first plurality of frequency bands, and said composite signal having a frequency spectrum in a respective second plurality of frequency bands excluding said first plurality of frequency bands, and

control means responsive to said steering means for generating a steering control signal having a plurality of components relating to the second plurality of frequency bands of said composite signal.

5. An encoder as claimed in claim 4, wherein bandwidths of said frequency bands are respectively approximately equal to the bandwidths of the critical bands of the human ear.

6. An encoder as claimed in claim 4, wherein said plurality of input signals represent input channels, and the steering control signal includes a control signal which represents a ratio of levels between the signals representing selected ones of the channels, in said second plurality of frequency bands of said composite signal.