Design And Research Of A Multimedia Communication Terminal With Low Frequency Channel Based On DSP

This paper mainly studies a DSP based multimedia phone. In order to solve the problem ofunbalanced numbers of users, the design gives usual phone more technical reformations to letthe ordinary telephone has a display and the most popular touch handwriting function. Thismultimedia phone using DSP (digital signal processor) as the kernel processor, and achievesthe function of data processing, software control and lots kind of information conversion.According to the information transmission mode with different frequency, it send two signalinto the telephone channel at the same time, not only completed the basic function of usualspeech communication, but also achieves the transmission of multimedia graphic textinformation, which makes life more convenient. This relative new communication terminalcan solve the depression of fixed telephone market effectively, and also can satisfy azero-noise communication in different environment both sides, avoiding the misunderstandingand differences of oral speech sounds between the south and north, and it also made a certaincontribution in communication technology. The terminal has the advantages of fancydesign,by making the communication more intuitive, flexible and convenient, at all,it makingcontributions to the solution of some sensitive social problem.Under the condition of making a private pipe by the hub, users only need to sendinformation to the other part by using their hand pointing at the LCD touch screen. Then theLCD driver will record the coordinate information by store up them in SDRAM. And what theDSP will do next is using the2DPSK algorithm to modulate the information in sequence, themodulated signal is turned into analog mode and sending into the telephone channel withvoice signal. The only different between2DPSK signal and voice signal is that the2DPSKsignal uses the high frequency and the voice signal uses the lower one.The frequency selective network will separate the voice signal and multimedia signal,then voice signal will be sent into the telephone for the audio communication, and themultimedia signal will be turned into digital signal. After that, the multimedia information isrestored to the image coordinate data by2DPSK differential coherent demodulation. After that,the coordinate data will be displayed on the LCD screen by the LCD driver. So, the one-way communication is complete. If the receive side want to send information back, they coulddirectly touch the screen to input information, then the two-way communication is complete.