2.4 GHz QPSK demodulator using MATLAB

Abstract

In everyday lives, technologies are increasing exponentially. It is means that communications are more reliable to make people life easier. It is true when communication abilities are not only surrounded by wires; but also wireless. However, majority waves propagations only available in analog signal, which is it only take a continuous infinity of values, while the information we want to transmit is digital, which means that it is sampled and quantized. This case only can be solved by using modulation techniques, which allow people to transmit any digital information over an analog carrier to the radio frequencies domain. The main reasons could be exposed here is to allows antennas to have reasonable sizes and to allows people to use a selected frequency band for transmission. It is also to provide much more possibilities of detection and so it provides more reliability. Modulated transmission is more efficient than direct transmission, but it implies more complexity in the design of the transmitter and the receiver. Unfortunately, digitizing a signal is not free of consequences concerning the quality of the output. The main concern is to determine the digital demand specifications so as to ensure sufficient quality at the end of the reception.