Design And Implementation Of Multi-functional Asynchronous Multiplex/demultiplex System For AES3/EBU Digital Audio Signal

With the popularity of digital broadcast and television,more and more studios,workstations,outside broadcast vehicles and other production systems are beginning to use the AES3/EBU digital interface for audio signal transmission.As the transfer rate of existing AES3/EBU digital interface devices is single and fixed,they can not meet the need of multi-rate transmission for digital broadcast and television devices.This paper studies an multi-functional asynchronous multiplex system based on FPGA for asynchronous AES3/EBU digital audio signal transmission.The AES3/EBU interface of the system not only adapts to multiple transmission rates,but also supports AES3/EBU encoding function of analog signal and decoding function of AES3/EBU signal.The whole system is composed of two parts: the transmitter and the receiver.The system is based on the digital multiple connection technique.The Xilinx Zynq XC7Z010 chip is used as the processor for the transmitter and the receiver.The transmitter executives the multiplexing of the multi-channel asynchronous AES3/EBU digital audio signal;The receiver completes the de-multiplexing of signal from the transmitter,and restores the AES3/EBU signal for each branch.The transmitter processes the multiple AES3/EBU digital signals which participate in digital multiplexing through the data recovery,AES3/EBU decoding,rate identification,positive justification,time division multiplexing,signal scrambling technique before they merged into a high-speed serial data stream to sent out.The sources of the AES3/EBU digital signal that can be multiplexed come from two aspects,one is from AES3/EBU digital audio signals sampled and encoded with 32/44.1/48/96 kHz for analog audio signals,the other is from the external AES3/EBU digital signal,and the sampling rate can be 32/44.1/32/44.1/192 kHz.The receiver processes high-speed serial data stream signal from the transmitter using the data recovery,descrambling,demultiplexing,positive justification recovery,clock digital smooth and other technologies for each channel AES3/EBU signal recovery.The recovered AES3/EBU signal keeps the original sampling rate.The receiver also supports the ability which decodes multiple AES3/EBU signals,then change them into analog audio signal outputs.The test results show that this syetem achieved the design goals,it realized multiplexing and demultiplexing of signals for unknown,asynchronous,multi-rate AES3/EBU digital audio signals;the receiver can restore the digital audio signal at the original sampling rate.