A Band pass filter (BPF) is used to block the unnecessary frequencies and allow only the required frequencies to pass further into a system, appliance, or application. An integrated system decides the requisite resonant frequencies and the unnecessary frequencies get removed with digital or a band pass filter.
In essence, the band pass allows only those signals that are required by the transmission parametric Signals outside of the specified band is attenuated but not completely rejected, which is termed as “roll-off”.
The pass filters help to keep such roll-offs to be as narrow as possible so that it performs as close to the designed parameters. This function prevents the wireless stations from a mix-up of frequencies resulting in a detrimental outcome.
Filters are divided into four groups, defined by their relative cut-off frequency values-High-pass, Low-pass, band-pass and band-stop filters.
Among the above groups, a band pass filter has two categories – Active and passive band pass filters. Active BPF uses active components like transistor and Op-Amp for filtering electronic signals and the passive BPF uses passive components like resistors, inductors, and capacitors to generate a frequency band.
Active BPF is highly effective in dealing with the very low frequencies-close to 0 Hz and yields a very high gain, however, is unsuitable for very high-frequency applications. Passive BPF is of utmost usefulness for the 100Hz to 300MHz frequency range.
Band pass filter is used in applications like power supplies, audio electronics, radio communications, and lighting equipment.
All types of filters are available from Raditek Inc. examples can be seen on the Raditek website.