英文高手进.滤波器（filter）,是一种用来消除干扰杂讯的器件,将输入或输出经过过滤而得到纯净的直流电.对特定频率的频

Filter is one kind of device for noise interference elimination during input and output to get clean direct current. Circuit for effective filtering of or off particular frequency point is called filter, which function is acquiring or eliminating one particular frequency. This article mainly introduces analysis and design of Q value tunable band-pass filter. Q value tunable band-pass filter is able to achieve the same function as common filter, that is useful signal undamped but useless signal extremely damped when signal is passing through. Besides, it is capable of changing Q value of filter to select signal of different bandwidth which increases filter’s flexibility. It is combined by one quality factor of tunable Double T Unit and Poor graded. By setting parameter of Double T Unit to make it to be Q value tunable band stop filter, after graded to get Q value tunable band-pass filtering. By regulation resistance to change Q value of filter, at the same time without changing mid-frequency and maximum gain. By circuit design simulation, bode plotter to get amplitude-frequency characteristics. With constant parameter regulation to gain the right parameters of filter, Q value tunable band-pass filter is achieved.
Key words: band-pass filter, Q value tunable, Double T Unit, poor graded