Avoidance of Electromagnetic Interference in Modem with Minimal Bit Error Rate Using Tele Typewriter Signals

Abstract

A Wireless Data Modem using Tele Typewriter Signals and Frequency Shift Keying (FSK) Modulation Technique is proposed here in order to neglect Electromagnetic Interference with minimal Bit Error Rate. The wireless modem designed here consists of 5 stages namely a) Modulation stage, b) Transmission stage, c) Reception stage, d) Filtering stage and e) Demodulation stage. The Modulation stage consists of IC555 Timer generating FSK signal. Transmission is wireless and is achieved using IRLED. The transmitted signal is received using a spectrally matched Phototransistor. The Filtering stage consists of a second order low pass filter. Demodulation is achieved using IC565. The modem designed here makes use of Tele Typewriter signals which neglects conduction and radiation interference from external environment. The Probability of error for this wireless data modem is better with minimal Bit Error Rate. Hence the whole setup is stable and accurate device for transmitting digital data. © Springer-Verlag Berlin Heidelberg 2010.