Irrigation is need of farmer to save water resource which is essential and need to use in minimum quantity because it is not free forever to use and not conversational resource. In drip irrigation water is given to root of plants to save water and stop land infertility and nutrition count. In irrigation farmer have to keep time table for irrigation which changes as per crop, soil and weather. Web based intelligent drip irrigation system is one and only solution to water management and precision agriculture. In web based system we can control water supply using solenoid valve. This whole system is micro control based and can be operated from remote location through web based so there is no need to concern about irrigation timing as per crop or soil condition. Sensor is used to take sensor reading of soil like soil moisture, temperature, air moisture and light micro controller take decision control by user (farmer). Web based intelligent irrigation system helps a farmer to take decision on water management in farm and there is no need to maintain irrigation time table .Irrigation time table can be fetch and map from agriculture university or government web site as per soil and crop type. It gives maximum profit from minimum cost.
Very recently the use of OFDM in optical systems has attracted increasing interest. Data rates in optical fiber systems are typically much higher than in RF wireless systems.The impairments caused by timing jitter are a significant limiting factor in the performance of very high data rate OFDM systems. In this letter we show that oversampling can reduce the noise caused by timing jitter. Both fractional oversampling achieved by leaving some band-edge OFDMsubcarriers unused and integral oversampling are considered. The theoretical results are compared with simulation results for the case of white timing jitter showing very close agreement. Oversampling results in a 3 dB reduction in jitter noise power for every doubling of the sampling rate.OFDM is a multicarrier modulation scheme that provides strong robustness against intersymbol interference (ISI) by dividing the broadband channel into many narrowband sub- channels in such a way that attenuation across each sub channel stays flat. Orthogonalization of sub channels is performed with low complexity by using the fast Fourier transform (FFT).
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