The Design And Realization Of Multi-channel Digital Synchronized Log For Control Unit In Real-Time Embedded Operating System

The Multi-channel Digital Synchronized Log (MDSL) is a high-tech product of the Institute of Image and Graphics of Sichuan University, which is used for recording large amounts of real-time multi-channel voices and Radar data, such as 16, 32 or 64 channel's data and thus is regarded as the typical real-time computer system. Because the function of real time largely depends on good hardware and system software, the present author and his partners apply the QNX operation system which is a highly reliable and rapidly responsive real-time operation system to the MDSL system.In the first chapter, the author makes an introduction to the basic theory of the MDSL. The MSDL as a comprehensive central control system is divided into two levels: the recording level is manipulated by more than one record unit computer to collect, replay and monitor voices and radar data and transfer information of various real-time status to the control unit at the same time; the supervisory control system is manipulated by one control unit computer to receive real-time information of the record units, voice (radar) channels and the network from the record unit and to produce different status icons so as to provide supervisors with relevant information and realize control of the record unit in compliance with the user's demands.In the second chapter, the author illustrates the characteristics of QNX operation system and explores for the realizing methods of the device driver in QNXoperation system. Considering that collecting voice data from ADPCM card is the key task in MDSL. he presents us his own new methods of reading data from ADPCM card, that is, memory- sharing method. At the end the author discusses the real-time feature through analyzing the device driver.In the third chapter, the author provides the specification and general design structure for the control unit of MDSL. He discusses different communication types between the record unit and the control unit and provides methods of how to resave data from the record unit and replay local voice data rapidly. The author also provides the algorithm for replaying local voice rapidly. At the end, the author illustrates user management, correcting clock, log management and network maintenance as well.Generally speaking, through the MDSL, we can realize effective application protocol in network communication, the function of real time and reliability; its clear and vivid man-machine interface in the control unit can present the supervisors information of different status vividly and directly.