Nrz

The ability of fiber optic to overcome the signal transmission problems is making it a dominant transmission medium. Despite of this major positive attribute of optic fibers, there is still a downside for using the fiber optic communication; that is the nonlinearity problem. For the first time, a design of an audio signal is suggested and executed in MATLAB with integration with OptiSystem TM  Software .The audio signal then transmitted in different shapes of modulation signals (NRZ, RZ, & RC) for different distances (100 km & 75 km) via a fiber optic media to be received in a receiving part of the simulated system. Three tests are used to do so. The first is the Quality-facto (Q-Factor) against the received power, second test is eye diagram performance and finally is the measuring of the amplitude of output (received) signal for each modulation signal shape using the Oscilloscope Visualizer. The NZR modulation signal was found to be the best one of the three used signals’ types in all three tests. The Q-factor for NRZ pulse shape (=12) was higher than that for RZ (=10) and RC (=8) for a 100 km distance at the same received power level.

Modern world is the world of internet which requires more capacity and more bandwidth to modernize the world. Hence we move towards optical communication. When we talk about optical communication then chromatic dispersion is biggest obstacle for high speed optical channel. Chromatic dispersion can be reduced either by compensation technique [1, 2] or either by electronic dispersion compensation. In this paper, we make comparative analysis in RZ and NRZ line encoding over 40 Gbps system. Two different modulation formats including non-return-to-zero (NRZ), return-to-zero (RZ) is compared on the basis of Bit error rate and quality factor. The 40 Gbps signal is transmitted over 200 km in single mode fiber.

Four Wave Mixing (FWM) is the parameter which restricts the transmission distance and bandwidth of optical communication systems. There are various factors which influence FWM, such as channel input power, spacing between channels, dispersion of fiber, operating wavelength and refractive index etc. The nonlinear effects tend to manifest themselves when optical power is very high and become important in WDM/DWDM systems. FWM suppression is required to overcome this problem. Techniques like, equal and unequal-channel spacing with varied laser power & alternate delay have been proposed to reduce the impact of FWM on Wavelength Division Multiplexing (WDM) optical communication system. Further the comparison of reduction of FWM for proposed techniques has been discussed by varying the dispersion of fiber from 0 to 16 ps/nm/km. Here, all the input channels have been spaced evenly at 100 GHz. The simulation results show that by increasing channel spacing, FWM reduces. It is observed that o...

The residual-carrier tracking performance for PCM/PSK/PM/NRZ for square-wave and sine-wave subcarriers will be evaluated as a function of the symbol SIW degradation. Explicitly, the RF residual carrier tracking performance will be defined in terms of the ...

Early morphogenic movements are an important feature of embryonic development in vertebrates. During zebrafish gastrulation, epiboly progression is driven by the coordinated remodeling of the YSL microtubule network and F-actin cables. We recently described the implication of Nrz, an anti-apoptotic Bcl-2 homolog, in the control of the YSL cytoskeleton dynamics. Nrz knock-down induces premature actin-myosin ring formation leading to margin constriction, epiboly arrest and embryo lethality. At the molecular level, the Nrz protein controls the actin-myosin dynamics through IP3R-dependent calcium levels variation. Here, we discuss these novel findings and propose a model in which reversible phosphorylation of the Nrz/IP3R complex modulates the permeability of the IP3R calcium channel and thus may explain the Nrz-dependent control of IP3R opening required for proper epiboly completion.

Performance limits of 10Gbit/s transmission over standard single mode fibre (SMF) without the deployment of in-line erbium-doped fibre amplifiers (EDFA's) are evaluated by means of numerical simulation. The fibre system was modelled using the standard split-step Fourier algorithm for the solution of nonlinear Schrodinger equation. The effect of group velocity dispersion (GVD) compensation scheme, degree of GVD compensation of the SMF, input optical powers to SMF and to the dispersion compensating fibre (DCF) has been investigated with the aim to maximize the distance between transmitter and receiver. We have found that post-compensation scheme performs better than the pre-compensation scheme and that, by careful selection of input powers and degree of GVD compensation, it should be possible to keep the bit-error-ratio (BER) bellow 10-15 for SMF length of 270 km.