ANATECH ELECTRONICS

A bandpass filter passes energy within a certain bandwidth and rejects frequencies below and above this bandwidth... A high-pass filter passes signals higher than a specified cutoff frequency and rejects signals below the cutoff frequency and performs the exact opposite function of a low-pass filter. The cutoff frequency is the frequency where the filter begins to make its transition from little attenuation to maximum or high attenuation. The frequency range above the cutoff frequency is the stopband region and the frequencies below it are the passband as shown in the figure... Awesome High Pass Filter site based on the Anatech electronics.