Development Of Ultra-High Definition HDMI Interface Audio Test Signal Sourc

In modern society,ultra-high definition and high-quality image display is an important way to improve people’s visual experience and quality of life.Major manufacturers are also committed to developing display devices that can support ultra-high definition video signals.In the process of production and testing,manufacturers need an audio and video test signal source that can continuously and stably output ultra-high definition HDMI interface.With the continuous improvement of resolution,the code rate of video signal transmitted by UHD HDMI interface is also increasing.The low code rate audio signal and high-speed video signal must be matched to achieve the effect of audio and video synchronization.In audio and video transmission,the sampling frequency of audio signal and video signal is different.The audio data in HDMI can only be transmitted driven by TMDS video pixel clock,and the original audio sampling clock is not retained.How to keep the synchronization of audio and video signals in audio and video signal source is the key problem.In addition,in the hardware design of audio and video signal source system,it is often realized by combined programmable logic device FPGA,DSP or single chip microcomputer.In this thesis,the large-scale programmable XC7A100 T FPGA chip of Artix-7 series with high integration is used.After in-depth research on the signal transmission principle of multimedia HDMI interface,the video signal with ultra-high bit rate can be generated,and the sound information with low bit rate can be embedded into the ultra-high definition video data stream,so as to complete the audio test signal source of ultra-high definition HDMI interface.Firstly,according to the ratio relationship between video pixel frequency and sound sampling frequency in UHD HDMI port signal,parallel sound signals corresponding to different output frequencies in different sound acquisition frequencies are generated;Then,the parallel audio signal is converted in series and inserted into the video signal,which is formed into TMDS signal through HDMI interface module,and finally sent to the video processing motherboard for verification.The audio test signal source of UHD HDMI interface in this thesis has the following characteristics:(1)The audio signal has the function of matching the video signal in ultra high definition and high definition HDMI interface.The digital audio signals of different code streams are generated in FPGA,which are matched with HD and UHD video signals of different code streams,and become audio and video signals transmitted in HDMI interface.(2)Integrated serial audio signal generation.The method of Direct Digital Synthesis(DDS)is used to generate audio signal,and the audio signal is converted into parallel series according to the transmission protocol.In the signal source,some special audio chips are avoided to improve the integration of the system.(3)Output the required audio signal on the parallel HDMI interface with multiple resolutions.In the process of production and testing,in order to match the audio and video signals with different resolutions and formats,different sources need to be changed frequently,which reduces the production efficiency.This thesis can output the required audio signal on the parallel HDMI interface with multiple resolutions as required,which is suitable for large-scale production and testing.