Simulation of Analog Modulation and Demodulation Techniques in Virtual Instrumentation and Remote Lab

Abstract

An analog method to modulate and demodulate signals is presented in this short paper. This paper discusses modulation techniques with the LabVIEW-based RF communications package, developed for the illustration of different modulation types in undergraduate virtual instrumentation labs. The tool can generate and display the time and frequency domain behaviours of modulated signals with the help of spectral and tone measurements icon. All the modulation parameters can be specified by the user. This signal processing tool in the block diagram is also enables adding noise to a modulated signal, and selecting among different types of baseband pulse-shaping filters. The transition between the virtual and the real world is accomplished via data-acquisition cards, installed in PCs. The results of simulation show that the interface of each system is beautiful, the parameters are easy to adjust and the process of modulation-demodulation is simpler than the traditional system which is designed by hardware circuit. This Amplitude modulation is tested in NI USRP RIO 2920 as transmitter. The carrier frequency used is 555-1650 KHz for amplitude modulation and the carrier frequency is 88-108 MHz in India.