Recognition of Analogue Modulations

Abstract

The current trend in modern communication systems is the use of digital modulation types rather than the analogue ones. However, the analogue modulations are still in use especially in the third world countries. So, the aim of this chapter is to discuss some of the available analogue modulation recognisers and to introduce some quick and fast algorithms for the well known analogue modulation types. The analogue modulation types that can be classified with the developed algorithms, introduced in this chapter, are: AM (with different modulation depths (60% and 80%)), DSB, VSB, LSB, USB, FM (with different modulation indices (5 and 10)), and combined modulated signals (with different modulation depths and different modulation indices). Furthermore, a non-intelligible simulated speech signal is used as a modulating signal for simulating the different types of analogue modulations to increase the degree of realism.