Audio Signal Processor Bridge Clock Synchronization
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Solution Overview
Problem
Existing network systems face limitations in the number of devices and physical length of transmission paths due to the need for frame circulation and word clock synchronization, leading to increased downtime when changing clock sources between different transmission paths.
Innovation Solution
An audio signal processor and system where devices operate as master and slave nodes, generating and transmitting audio frames with independent sampling clocks, allowing for seamless synchronization and reduced downtime during clock source changes by using bridge devices to manage clock generation and transmission across multiple networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple transmission paths are connected through a bridge device, then the number of devices and physical length of transmission path can be increased, but the transmission-impossible time increases when changing clock source to a device in a different transmission path
Solution Approach 1:
The bridge device preliminarily generates a sampling clock independently before any frame reception disconnection occurs. This preliminary action ensures that when the clock source needs to be changed to a device in a different transmission path, the sampling clock is already available, eliminating the transmission-impossible time that would otherwise occur during clock source transition.
Solution Approach 2:
The bridge device acts as an intermediary between multiple transmission paths by generating and managing the sampling clock independently. It mediates the clock distribution to slave devices, allowing seamless switching between clock sources from different transmission paths without causing transmission interruptions.
2Reliability
If frame circulation is implemented for stable transmission, then signal stability is improved, but the physical length of transmission path and number of devices are restricted
Solution Approach 1:
The system segments the network into multiple independent transmission paths connected through a bridge device. Each transmission path can independently circulate frames, allowing the system to extend the total physical length and number of devices by adding more segments without compromising the frame circulation stability within each segment.
Solution Approach 2:
The bridge device provides multi-functionality by serving as both a frame forwarding device and an independent sampling clock generator. It can receive frames from multiple transmission paths and forward them while simultaneously providing clock synchronization, enabling the system to accommodate longer transmission paths and more devices while maintaining stability.
3Ease of operation
If word clock is transmitted through frame circulation, then synchronized sampling clocks are generated in each node, but the system experiences downtime when word clock source changes to a different transmission path
Solution Approach 1:
The bridge device preliminarily generates a sampling clock independently before any clock source change is needed. This ensures that when the word clock source needs to be switched to a device in a different transmission path, the sampling clock is already available and synchronized, eliminating downtime during the transition.
Solution Approach 2:
The system changes the operational parameter of the bridge device from purely forwarding frames to independently generating sampling clocks. This parameter change allows the bridge device to maintain continuous clock output regardless of which transmission path's word clock source is active, thereby eliminating synchronization downtime during clock source changes.
Data Source
AI summary
Even when a system is made to have a configuration in which a plurality of transmission paths are connected to each other, a transmission-impossible time in each transmission path caused by changing a clock source to a device of a different transmission path can be shortened. In an audio signal processing system including first and second networks connected to each other through a bridge device, the bridge device operates as a slave in the first network and as a master in the second network. When the second network is reset, the bridge device starts to operate as a slave in the second network. Then, when continuous reception of an audio transmission frame that another device operating as a master in the second network has transmitted is started, the bridge device resets the first network and starts to operate as a master in the first network.