Digital transmission system, transmitter and receiver for use in the transmission system

• US 5,323,396 A
• Filed: 12/21/1992
• Issued: 06/21/1994
• 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: Lokhoff, Gerardus C. P.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): TON, DANG T
• Application Number:
  US07/997,158
• Time in Patent Office: 547 Days
• Field of Search: 370/94.1, 370/60, 370/84, 370/82, 370/83, 370/100.1, 370/103, 370/105.1, 370/106, 370/105.4, 375/25, 375/26, 375/122, 360/31, 360/5-8, 360/18, 360/19.1, 381/29, 381/31, 381/30, 381/32-40
• US Class Current: 370/468
• 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

Digital data are transmitted as packets within frames, at an average frame rate equal to the sampling rate divided by the number of samples per frame. When, as a result of subband or other coding, the number of packets required per frame would not be an integer, frames containing the next lower integer are transmitted, followed by frames containing the next higher integer. Preferably a first portion of each frame contains synchronization information, a second portion contains allocation information, and a third contains samples of, and scale factor information for, the transmitted signal.

Claims

1. A digital transmission system comprising a transmitter and a receiver, for transmitting wide-band digital information having a sample frequency F, via a transmission medium, and for receiving said information,

said transmitter having an input terminal for receiving said information to be transmitted, in the form of a first digital signal;

an output; and

a signal source, having an input coupled to said input terminal, for generating and supplying to said output a second digital signal which includes said information, said second digital signal comprising consecutive frames, each frame comprising a plurality of information packets, and each information packet comprising N bits, where N>

1,

said receiver comprising a decoder and an output terminal, said decoder having an input for receiving said second digital signal and an output coupled to said output terminal for supplying said wide-band digital information,

characterized in that, in the formula ##EQU4## where BR is the bit rate of said second digital signal, and n_s is the number of samples of said information whose corresponding information in said second signal is included in one frame of said second signal,

if P is an integer, the number of information packets in one frame is P, and

if P is not an integer, the number of information packets in a number v of the frames is P'"'"', where P'"'"' is the highest integer whose value is less than P; and

the number of information packets in a number w of the other frames is p'"'"'+1, the numbers v and w being selected such that the average frame rate of said second digital signal is substantially equal to F_s /n_s, and that each frame comprises at least a first frame portion including synchronizing information.

2. A transmission system as claimed in claim 1, characterized in that the first frame portion contains further information related to the number of information packets in the frame.

3. A transmission system as claimed in claim 1, characterized in that a frame comprises a first frame portion, a second frame portion and a third frame portion, the first frame portion further including system information and the second and the third frame portion including signal information.

4. A transmission system as claimed in claim 1, characterized in that if a frame comprises P'"'"'+1 information packets, the first frame portion contains information corresponding to P'"'"'.

5. A transmission system as claimed in claim 3, the transmitter comprising a coder comprising signal-splitting means responsive to the first digital signal to generate said second digital signal in the form of a number of M subsignals, M being larger than 1, and comprising means for quantising the respective subsignals, characterized in that the second frame portion of a frame contains allocation information which, for at least a number of subsignals, indicates the number of bits representing the samples of the quantised subsignals derived from said subsignals, and in that the third frame portion contains the samples of at least said quantised subsignals.

6. A transmission system as claimed in claim 5, in which the signal-splitting means take the form of analysis-filter means responsive to the first digital signal to generate a number of M subband signals, which analysis-filter means divide the signal band of the first digital signal, applying sample-frequency reduction, into successive subbands having band numbers m increasing with the frequency, and in which the quantisation means are adapted to quantise the respective subband signals block by block, characterized in that for at least a number of the subband signals the allocation information in the second frame portion of a frame specifies the number of bits representing the samples of the quantised subband signals derived from said subband signals, and in that the third frame portion contains the samples of at least said quantised subband signals.

7. A transmission system as claimed in claim 6, characterized in that in addition the third frame portion includes information related to scale factors, a scale factor being associated with at least one of the quantised subband signals contained in the third frame portion, and in that the scale factor information is included in the third frame portion before the quantised subband signals.

8. A transmission system as claimed in claim 6, in which the receiver decoder comprises synthesis-filter means responsive to the respective quantised subband signals to construct a replica of the first digital signal, which synthesis filter means combine the subbands, applying sample frequency restoration to form the signal band of the first digital signal, characterized in that said samples of the quantized subband signals are inserted in the third frame portion in a sequence corresponding to the sequence in which said samples are applied to the synthesis-filter means upon reception in the receiver.

9. A transmission system as claimed in claim 8, characterized in that the allocation information for the various quantised subband signals is inserted in the second frame portion in a similar sequence.

10. A transmission system as claimed in claim 9, characterized in that in addition the third frame portion includes information related to scale factor, a scale factor being associated with at least one of the quantised subband signals contained in the third frame portion, and in that the scale factor information is included in the third frame portion before the quantised subband signals, and the scale information for the scale factors is inserted in the third frame portion in a sequence corresponding to the sequence in which the allocation information for the quantised subband signals associated with said scale factors is included in the second frame portion.

11. A transmission system as claimed in claim 6, the first digital signal comprising a first and a second signal component, the analysis-filter means being adapted to be responsive to the first and the second signal components to generate a number of M subband signals, each subband signal comprising a first and a second subband signal component, the means being further adapted to quantise the respective first and second subband signal components in a specific subband, characterized in that the second frame portion of a frame includes allocation information specifying for said specific subband the number of bits representing the samples of the quantised first and second subband signal components derived from each of the two subband signals of said specific subband, and in that the third frame portion includes samples of said quantised first and second subband signal components.

12. A transmission system as claimed in claim 11, characterized in that in addition the third frame portion includes information related to scale factor, a scale factor being associated with at least one of the quantised subband signals contained in the third frame portion, and in that the scale factor information is included in the third frame portion before the quantised subband signals, and the third frame portion includes scale-factor information for two scale factors for said specific subband, each scale factor belonging to the first or the second quantised subband signal component of said subband.

13. A transmission system as claimed in claim 11, in which the receiver decoder comprises synthesis filter means responsive to the respective quantised subband signal components to construct a replica of the first digital signal comprising the first and the second signal component, characterized in that the samples of the subband signal components (if present) are inserted in the third frame portion in a sequence corresponding to the sequence in which the samples of said subband signal components are applied to the synthesis filter means upon reception in the receiver.

14. A transmission system as claimed in claim 13, characterized in that the allocation information for the various quantised subband signal components is inserted in the second frame portion in a similar sequence.

15. A transmission system as claimed in claim 14, characterized in that in addition the third frame portion includes information related to scale factor, a scale factor being associated with at least one of the quantised subband signals contained in the third frame portion, and in that the scale factor information is included in the third frame portion before the quantised subband signals, and the scale-factor information for the scale factors is inserted in the third frame portion in a sequence corresponding to the sequence in which the allocation information for the first and second quantised subband signal components belonging to said scale factors are inserted in the second frame portion, and in that the scale-factor information is inserted in the third frame portion before said samples of the quantised subband signal components.

16. A transmission system as claimed in claim 5, characterized in that the (P'"'"'+1)-st information packet does not contain any useful information.

17. A transmission system as claimed in claim 3, characterized in that the frames comprise a fourth frame portion in which error-detection and/or error-correction information is included.

18. A transmission system as claimed in claim 2, characterized in that a frame comprises a first frame portion, second frame portion and a third frame portion, the first frame portion further including system information and the second and the third frame portion including signal information.

19. A transmission system as claimed in claim 2, characterized in that if a frame comprises P'"'"'+1 information packets, the first frame portion contains information corresponding to the value P'"'"'.

20. A transmission system as claimed in claim 19, the transmitter comprising a coder comprising signal-splitting means responsive to the first digital signal to generate said second digital signal in the form of a number of M subsignals, M being larger than 1, and comprising means for quantising the respective subsignals, characterized in that the second frame portion of a frame contains allocation information which, for at least a number of subsignals, indicates the number of bits representing the samples of the quantised subsignals derived from said subsignals, and in that the third frame portion contains the samples of at least said quantised subsignals.

21. A transmission system as claimed in claim 3, characterized in that if a frame comprises P'"'"'+1 information packets, the first frame portion contains information corresponding to the value P'"'"'.

22. A transmission system as claimed in claim 21, the transmitter comprising a coder comprising signal-splitting means responsive to the first digital signal to generate said second digital signal in the form of a number of M subsignals, M being larger than 1, and comprising means for quantising the respective subsignals, characterized in that the second frame portion of a frame contains allocation information which, for at least a number of subsignals, indicates the number of bits representing the samples of the quantised subsignals derived from said subsignals, and in that the third frame portion contains the samples of at least said quantised subsignals.

23. A transmission system as claimed in claim 7, in which the receiver decoder comprises synthesis-filter means responsive to the respective quantised subband signals to construct a replica of the first digital signal, which synthesis filter means combine the subbands, applying sample frequency restoration to form the signal band of the wide-band digital signal, characterized in that the samples of the subband signals are inserted in the third frame portion in a sequence corresponding to the sequence in which said samples are applied to the synthesis-filter means upon reception in the receiver.

28. A system as claimed in claim 1, wherein a same number n_s of samples of said information are included in each said frame of said second signal.

29. A system as claimed in claim 5, wherein said number n_s is 384.

24. A transmitter for transmitting wide-band digital information having a sample frequency F, via a transmission medium, comprising:

an input terminal for receiving said information to be transmitted, in the form of a first digital signal,

an output, and

a signal source, having an input coupled to said input terminal, for generating and supplying to said output a second digital signal which includes said information, said second digital signal comprising consecutive frames, each frame comprising a plurality of information packets, and each information packet comprising N bits, where N>

1,

characterized in that, in the formula ##EQU5## where BR is the bit rate of said second digital signal, and n_s is the number of samples of said information whose corresponding information in said second signal is included in one frame of said second signal,

if P is an integer, the number of information packets in one frame is P, and

if P is not an integer, the number of information packets in a number v of the frames is P'"'"', where P'"'"' is the highest integer whose value is less than P; and

the number of information packets in a number w of the other frames is p'"'"'+1, the numbers v and w being selected such that the average frame rate of said second digital signal is substantially equal to F_s /n_s, and that each frame comprises at least a first frame portion including synchronizing information.

25. A transmitter as claimed in claim 24, where said transmission medium is a record carrier, said transmitter being formed as a device for recording said second digital signal in a track on said record carrier.

30. A transmitter as claimed in claim 24, wherein a same number n_s of samples of said information are included in each said frame of said second signal.

31. A transmitter as claimed in claim 25, wherein said number n_s is 384.

26. A receiver for receiving wide-band digital information having a sample frequency F_s transmitted over a transmission medium, having an output at which said information is provided in the form of a first digital signal, and a decoder for receiving said information in the form of an encoded second digital signal which comprises consecutive frames, each frame comprising a plurality of information packets, and each information packet comprising N bits, where N>

1,

characterized in that, in the formula ##EQU6## where BR is the bit rate of said second digital signal, and n_s is the number of samples of said information whose corresponding information in said second signal is included in one frame of said second signal,

if P is an integer, the number of information packets in one frame is P, and

if P is not an integer, the number of information packets in a number v of the frames is P'"'"', where P'"'"' is the highest integer whose value is less than P; and

the number of information packets in a number w of the other frames is p'"'"'+1, the numbers v and w being selected such that the average frame rate of said second digital signal is substantially equal to F_s /n_s, and that each frame comprises at least a first frame portion including synchronizing information.

27. A receiver as claimed in claim 26, characterized in that said transmission medium is a record carrier, and that said receiver is formed as a device for reading said second digital signal from a track on said record carrier.

32. A receiver as claimed in claim 26, wherein a same number n_s of samples of said information are included in each said frame of said second signal.

33. A receiver as claimed in claim 27, wherein said number n_s is 384.