VARIABLE METHOD OF SYNTHESIS OF THE ELEMENTAL SIGNAL WITH MINIMUM ENERGY OUTSIDE OF WORKING FREQUENCY

Abstract

It is shown in the paper that the synthesis of the signal of the optimum form is an extreme problem, the variational nature of which allows to apply the ideas and methods of functional analysis to its solution. Variational calculus was applied to study the extreme properties of the functional. You have just been described describing the form of a finite-element elementary signal with minimal energy outside the operating frequency band. In fiber optic transmission systems, direct modulation of optical radiation is widely used by varying the pumping current of a semi-subtractive laser, which is due to the simplicity and low cost of the modulator. The disadvantages of direct modulation are the nonlinear dependence of the radiation power on the pump current and parasitic frequency modulation or the dynamic expansion of the spectrum of the optical modulated signal, which does not allow the use of effective modulation methods. Advanced fiber-to-wave transmission (WDM) systems at 40, 100 Gbps and above transmit rates utilize external modulation to increase frequency efficiency and bandwidth. Synthesis of the optimum form signal is an extreme task, the variational nature of which enables the ideas and methods of functional analysis to be solved. In advanced telecommunication systems with software-defined logic, the elementary signal with the minimum active spectrum can be approximated by a step function using the Walsh function. It is of interest to determine the maximum step of a step signal that provides the induced damping of nonlinearity, which is the subject of further-to-followings.