Network system and audio signal processor

• US 20080240459A1
• Filed: 09/13/2007
• Published: 10/02/2008
• Est. Priority Date: 09/13/2006
• Status: Active Grant

• Current Assignee: Yamaha Corporation
• Original Assignee: Yamaha Corporation
• Inventors: Nakayama, Kei, Yamaguchi, Naoto
• Granted Patent: US 8,103,369 B2
• Time in Patent Office: Days
• US Class Current: 381/77
• CPC Class Codes: H04J 3/062 Synchronisation of signals having the same nominal but fluctuating bit rates, e.g. using buffers pulse-stuffing H04J3/07; asynchronous-synchronous conversion H04L5/24; speed conversion H04L25/05; speed conversion in computers G06F5/06
• CPC Class Codes: H04J 3/0691 Synchronisation in a TDM node
• CPC Class Codes: H04J 3/085 for ring networks, e.g. SDH/SONET rings, self-healing rings, meashed SDH/SONET networks
• CPC Class Codes: H04L 12/40169 Flexible bus arrangements arrangements for maintenance or administration involving management of faults; events, alarms H04L41/06; automatic restoration of network faults H04L41/0654
• CPC Class Codes: H04L 12/42 Loop networks
• CPC Class Codes: H04L 12/437 Ring fault isolation or reconfiguration for SDH/SONET ring networks H04J3/085

Abstract

An audio network system that performs transport of audio signals among nodes by cascading a plurality of nodes each including two sets of transmission I/Fs and reception I/Fs, and circulating among the nodes in each fixed period an audio transport frame generated by a master node, the audio transport frame including a plurality of storage regions for audio signals, is configured such that the master node stores a frame packet after circulating among the nodes and returning thereto into a buffer, so as to generate the audio transport frame in the (S+k)-th period based on the audio transport frame in the S-th period when the audio transport frame in the S-th period has been normally received, or based on a predetermined model otherwise.

Claims

1. A network system configured such that a plurality of nodes each comprising receivers and transmitters are connected in series by communication cables to form a loop transmission route along which an audio transport frame periodically circulates in a single direction, said audio transport frame generated by a master node in said plurality of nodes, said audio transport frame comprising a plurality of storage regions for audio signals,

wherein each of said nodes other than said master node comprises:

a reader that reads out, when said receiver receives the audio transport frame, audio signals from a predetermined storage region of the audio transport frame, and/or a writer that writes audio signals into a predetermined storage region of the audio transport frame received by said receiver; and

a transmission controller that supplies the audio transport frame from/to which reading-out by said reader and/or writing by said writer have been performed to said transmitter, and controls said transmitter to transmit the audio transport frame after a lapse of a predetermined time from a timing at which said receiver receives the audio transport frame, and

wherein said master node comprises;

a buffer that stores the audio transport frame received by said receiver;

a wordclock generator that generates a wordclock at a constant period,

a judging device that judges whether the audio transport frame received by said receiver has circulated normally along the loop transmission route or not;

an audio transport frame generator that generates the audio transport frame in an (S+k)-th period later than an S-th period by k periods (where k is an integer of 2 or more), based on the audio transport frame in the S-th period when said judging device judges that the audio transport frame in the S-th period of the audio transport frames stored in said buffer has circulated normally, or based on a predetermined model when said judging device judges that the audio transport frame in the S-th period has not circulated normally;

a reader that reads out, when said receiver receives an audio transport frame in the S-th period, audio signals from a predetermined storage region of the audio transport frame in the S-th period or an audio transport frame in the (S+k)-th period generated by said audio transport frame generator based on the received transport frame, and/or a writer that writes audio signals into a predetermined storage region of either of the audio transport frames; and

a transmission controller that supplies the audio transport frame in the (S+k)-th period generated by said audio transport frame generator to said transmitter, and controls said transmitter to transmit the audio transport frame in synchronization with the wordclock in the (S+k)-th period.

2. A network system according to claim 1, wherein said k is a fixed value.

3. A network system according to claim 1,

wherein any of said nodes is provided with a setting device that sets the value of k common to said each node.

4. A network system according to claim 1,

wherein said predetermined model is the latest audio transport frame in said buffer which was received before the audio transport frame in the S-th period judged to have not been normally received, and judged to have been normally received.

5. A network system according to claim 1,

wherein said predetermined model is an audio transport frame in which all of the audio signals stored in the storage region for the audio signals have a predetermined value or a predetermined code.

6. A network system according to claim 1,

wherein said master node comprises

a signal processor that process audio signals, and

wherein in said master node having said reader,

said reader supplies the audio signals read out from the audio transport frame to said signal processor in synchronization with the wordclock.

7. A network system according to claim 1,

wherein each of said nodes other than said master node comprises:

a wordclock generator that generates a wordclock based on a reception timing of the audio transport frame received by said receiver, and

a signal processor that processes audio signals, and

wherein in each of said nodes other than said master node and having said reader,

said reader supplies the audio signals read out from the audio transport frame to said signal processor in synchronization with the wordclock.

8. A network system according to claim 7,

wherein in each of said nodes other than said master node and having said reader,

when said receiver receives the audio transport frame generated based on said predetermined model, said reader supplies to said signal processor only the audio signals written by another node in the transmission route from said master node to the node.

9. A network system according to claim 8,

wherein said audio transport frame comprises a region for abnormality notification data,

wherein in said master node,

said audio transport frame generator includes a device that sets, when said audio transport frame generator generates the audio transport frame based on said predetermined model, said abnormality notification data in the audio transport frame a value indicating the audio frame is generated based on said predetermined model, and

wherein in each of said nodes comprises,

a judging device that judges whether the audio transport frame received by said receiver has been generated based on said predetermined model or not, based on said abnormality notification data in the audio transport frame.

10. A network system according to claim 7,

wherein each of said nodes other than said master node has a judging device that judges whether the audio transport frame whose reception has been completed is normal or not, and

wherein said reader supplies to said signal processor the audio signals read out from the audio transport frame judged to be normal and does not supply to said signal processor the audio signals read out from the audio transport frame judged to be not normal.

11. A network system according to claim 8,

wherein said reader comprises a supplementing device, and

wherein when the received audio transport frame has been generated based on said predetermined model, and therefore said reader of said each node does not supply the audio signals stored in a certain storage region of the audio transport frame to said signal processor, said supplementing device supplies to said signal processor, in place of the audio signals, the audio signals supplied to said signal processor in the preceding period.

12. A network system according to claim 7,

wherein said reader comprises a supplementing device, and

wherein when the audio transport frame whose reception has been completed is not normal, and therefore said reader of said each node does not supply the audio signals stored in a certain storage region of the audio transport frame to said signal processor, said supplementing device supplies to said signal processor, in place of the audio signals, the audio signals supplied to said signal processor in the preceding period.

13. A network system according to claim 11,

wherein said supplementing device performs attenuation or low cut filter processing on the audio signals supplied to said signal processor in the preceding period and supplies the resulting audio signals to said signal processor.

14. A network system according to claim 12,

wherein said supplementing device performs attenuation or low cut filter processing on the audio signals supplied to said signal processor in the preceding period and supplies the resulting audio signals to said signal processor.

15. The network system of claim 1 wherein one of said plurality of nodes is an audio signal processor.

16. A network system according to claim 1,

wherein each of said nodes other than said master node comprises

a judging device that judges whether the audio transport frame whose reception has been completed is normal or not, and

wherein in said master node,

said judging device judges that the audio transport frame received by said receiver has not circulated normally along said loop transmission route in the case when said judging device if any one of said plurality of nodes in said loop transmission route judges that the audio transport frame is not normal, during the audio transport frame circulates said loop transmission route in the network system.

17. A network system according to claim 16,

wherein each of said nodes other than said master node comprises

a repairing device that repairs the audio transport frame when said judging device in the node judges the audio transport frame is not normal, and

wherein in each of said nodes other than said master node,

said transmitter transmits the audio transport frame repaired by said repairing device to the next node when said judging device in the node judges that the audio transport frame is not normal.

18. A network system according to claim 17,

wherein the audio transport frame including a storage region for repair notification data, and

wherein in said master node,

said audio transport frame generator includes a device that sets said repair notification data in the audio transport frame with a value corresponding to a non-repaired status when said audio transport frame generator generates the audio transport frame, and

wherein in each of said nodes other than said master node,

said repairing device sets said repair notification data in the audio transport frame with a value corresponding to a repaired status when said repairing device repairs the audio transport frame.

19. A network system according to claim 18,

wherein each of said nodes other than said master node comprises

a signal processor that processes audio signals, and

wherein in each of said nodes other than said master node and having said reader,

said reader supplies the audio signal read out from the audio transport frame to said signal processor if said judging device in the node judges that the audio transport frame is normal and said repair notification data in the audio transport frame indicating “

not repaired”

.

20. A network system according to claim 18,

wherein in said master node,

said judging device judges whether the audio transport frame received by said receiver is normal or not, based on said repair notification data and an error check code in the audio transport frame.

21. A network system according to claim 1,

wherein each of said nodes other than said master node comprises

a judging device that judges whether the audio transport frame whose reception has been completed is normal or not, and

wherein in each of said nodes other than said master node and having said reader,

said reader supplies the audio signal read out from the audio transport frame to said signal processor if said judging device in the node judges that the audio transport frame is normal, and

said transmitter transmits the audio transport frame without repair to the next node when said judging device in the node judges that the audio transport frame is not normal.