Title: BIT ERROR RATIO CONCEPT AND 3D EYE DIAGRAM TO ANALYSIS OF M STATE DIGITALLY MODULATED SIGNALS

Issue Number: Vol. 1, No. 2
Year of Publication: 2011
Page Numbers: 384-393
Authors: Mohamed Al-Wohaishi, Jan Zidek
Journal Name: International Journal of Digital Information and Wireless Communications (IJDIWC)
- Hong Kong

Abstract:


When designing digital systems and incorporating a high-speed digital device with the need of quick transfer of large data amounts between chips and peripherals, jitter will be a key parameter to measure. In this paper, we are able to determine the initial phase of a carrier sine wave by performing carrier recovery loop in Digital communication systems of M-ary quadrature amplitude modulation (M-QAM) schemes. It is important for the M-ary QAM carrier recovery circuits to have low phase jitter as well as only four stable phase points as we see below. We examined the effect of channel noise on carrier recovery. More specifically, we examined what behaviour can occur when channel noise is significant enough to prevent carrier locking. We saw the symbols on the 3D Eye Diagram and constellation plot begin to jitter at first, and then settle closer to the ideal symbol locations after a short period of time. Authors of this article present real results, which illustrate the link between number of symbols in M-state QAM modulation, SNR and BER. Constellation diagrams of transmitted and received symbols (with superposition of noise) were presented in the article. Simple picture is transmitted through simulated radio channel to show the result of signal impairments. Modular PXI HW platform was used in connection with graphically oriented development environment. This combination of modular HW and flexible SW components allows changing the communication protocol, modulation scheme, frequency bandwidth and other parameters in a very simple way by changing the software part of the system.