This scheme designs a voice conference system based on ZigBee transmission wireless sensor network structure. Each microphone acts as a node in the wireless sensor network, and all microphones form a wireless sensor network. The sound data of the microphone is uploaded to the aggregation node through ZigBee transmission, and the aggregation node is forwarded to the sound reinforcement system. This design effectively solves the problem that the transmission distance is too long and some dead angle positions cannot be transmitted. 1 Wireless sensor network introduction and characteristics Wireless Sensor Network (WSN) is a network of sensor nodes that can monitor, sense, and collect various information of the perceptual objects of interest to observers in the node deployment area in real time, and process the information. It is sent wirelessly and finally sent to the viewer over the wireless network. Wireless sensor networks have the following characteristics: 1 There is no strict control center in the wireless sensor network. The entire wireless sensor network is a peer-to-peer network, and each node in the network can join or leave the network at any time. 2 The layout and deployment of the network does not need to depend on other preset network facilities. The nodes can coordinate their respective behaviors through layered protocols and distributed algorithms. After the nodes are started, they can quickly and automatically form an independent wireless network. 3 There is no special routing device in the wireless sensor network. The multi-hop routing of nodes is completed by common network nodes. Each node can send information and forward information, which can effectively avoid the problem that some nodes cannot communicate with the route. 4 Wireless sensor network is a dynamic network, nodes can move anywhere, can exit the network for some reason, or can be added to the network for some reason. The network structure can be dynamically changed and very flexible. 2 system structure design The system structure diagram is shown in Figure 1. Each participant's microphone acts as a node of the wireless sensor network. As shown in the circular diagram on the left in Figure 1, each node can communicate directly with the aggregation node. Some nodes (maybe because they are too far away or blocked by obstacles) cannot Directly communicate with the aggregation node, and can communicate with the aggregation node indirectly through forwarding of other intermediate nodes (black nodes in the figure), and even route through the multi-level child nodes to the aggregation node. Figure 1 system structure diagram The sink node transmits the sound signal sent by the child node to the sound reinforcement system after being decoded by audio. At the same time, when some conference systems need simultaneous interpretation, there will be sub-nodes of simultaneous interpretation in the system. The simultaneous interpretation node acts as a special sub-node, and the translation data is directly sent to the aggregation node, which is then forwarded by the aggregation node. Each child node. The child node selects the corresponding language according to the user's needs, and is limited by the ZigBee bandwidth. The number of channels that can support simultaneous interpretation is limited. Variable Frequency AC Power Supplies The VFP series AC Power Supplies are high precision, high efficiency, low THD adjustable AC power supplies that converts the input mains power through AC→DC→AC conversion, and gives a pure sine wave AC output with adjustable voltage & frequency within a certain range. Also known as Variable Frequency AC Power Source.
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