Optimal Design of Improved Butterworth Filter Based on Optical Fiber Terminal

An improved five-order active Butterworth filter is designed according to characteristics of input video signal.Sampling frequency is increased to reduce filter order,the group delay and the frequency characteristic of the filter are also adjusted,and quality of input video signal is improved.The reconstruction filter is built with specialized chip for filtering and driving of the output video signal.The fiber transmitting and processing terminal including improved filter and programmable controller is implemented.Simulation and experimental results show that the designed filter has the characteristics of flatter passband,bigger stop-band attenuation,and better group delay in the passband.