active band pass filter的用法和样例：
- The duplexer acts as a very broad band pass filter during receiving mode and the prearnp is a low noise wide band-width amplifer that is used to amplify the echo signals.
- The signal processing system consists of a band pass filter(BPF) with center frequency of 2.856 GHz and bandwidth of 10 MHz,a logarithmic detector,a analog digital converting module,and a data acquisition program based on Labview.
- By modeling the 2-finger FET into CPW, the on-state millimeter-wave traveling wave switches are equivalent to the step impedance band pass filter and the design procedure is obtained.
- First,a finite impulse respond(FIR) band pass filter is designed based on Chebyshev approximation method,and then the windowed impulse response is used to adjust energy distribution of signal.