Tracking down wireless noise
9 May 2007
Graphical models enable users to observe the impact of impairments on communications systems
London -- National Instruments is highlighting how its Modulation Toolkit for LabVIEW can be used to create graphical models of complex wireless systems that enable users to observe the impact of impairments on the system.
Wireless digital communications systems use discrete changes in the phase, frequency, or amplitude of an RF carrier signal to transmit digital information. The changes (termed “symbols,”) each represent a unique state of the carrier signal.
One common modulation scheme, quadrature amplitude modulation (QAM), can use anywhere from four to 256 symbols. However, the presence of noise in a communications channel can prevent the receiver from accurately detecting the state of the RF carrier.
According to NI, the Modulation Toolkit can interactively model a wireless system to simulate a common impairment to the physical channel by applying additive white Gaussian noise (AWGN) to the modulated carrier signal.