Modem is a basic equipment for, data transmission. As conputer and other digital systems are becoming widely used, the demand of a high speed modem is rapidly increasing. In this thesis study, en efficient method of microprocessor-based hardware realization of a 9600 bps voice-band modem has been studied.
The study is precede in three areas as follows. First, the modem structures for high speed data transmission, especially equalizer and symbol timing structures, have been studied by conputer simulation. Second, a 9600 bps modem hardware using bit slice 2900 series microprocessor has been designed and implemented. Third, software based on computer simulation and hardware design has been developed. The control of the overall system is maded by microprograms consisted of 56 bits microinstruction. To increase system throughput the approach of parallel operation of microinstruction has been used. To manipulate the system firmware efficiently, the convenient microinstruction field definitions and neumonic nemes have been considered. In developing the firmware, microprogramming schemes to reduce execution time have been studied.
본 논문에서는 telephone line용 modem으로서 가장 high speed인 9600 bps modem을 rea1ize하기 위한 hardware와 software가 중점적으로 연구되었다.
첫째, 9600 bps modem의 기본 function이 연구되었으며 특히 QAM system의 특성과 telephone line에서의 delay distortion 및 noise를 제거할 수 있는 equalizer structure 및 symbol timing recovery structure가 중점적으로 논의되었다.
둘째, hardware구성은 AMD-2900계열의 bit slice niicroprocessor를 사용하여 microprogramming system을 구성시킴으로써 one processor에 의해 모든 function이 수행될 수 있도록 designe 되었다.
세째, firmware 개발과정에서 효율적으로 program 할 수 있도록 field definition 과 neumonic nam이 define되었으며 또한 filter 및 equalizer에서 execution time을 최소한으로 줄일 수 있는 scheme들이 연구되었다.
