A kind of single tuned filter based on controllable reactor is introduced,which is reformed from passive into active to avoid the influence of parameter change on resonance frequency.

To eliminate the mis-tuning of a single tuned filter, an experimental system of auto-tuned filter with a continuously tunable reactor is developed, and an auto-tuning technique is introduced into the filter.

This thesis analyses the characteristic of single tuned filter and high pass filter,puts forward some design ideas of filter,and gives some examples.

In general the circuit topology of multi-tuned filter consists of one series branch and multi-parallel branches.

With the extensive application of power electronic techniques, some new structures, such as auto-tuning filter and continuously multi-tuned filter have brought great improvement of filter performance.

A switching type power amplifier based on power electronic techniques is used to amplify the compensation current,the simulation model of the multi-tuned filter with multiple compensation windings is established,and the experimental system is developed.

For these reasons the tuned filter must be used when the reactive compensation is done at the existing of system harmonic so as to fulfill the following tasks:do reactive.

The newly developed auto-tuned filters are introduced in this paper.

Single tuned filter is made of capacitance.

The study of multiple-cavity RF tunable filter;

After explaining how to exploit the huge potential capacity of the optical fiber in order to realize high bit rate communication, the paper describes the components used for the wavelength division multi access communication network, particularly the tunable filters and lasers as .

The effect of classic voltage and liquid crystals material parameters on tunable filter transmission spectrum was numerically calculated.