The bandwidth in the filter is solely the distinction between the higher and lower cutoff frequencies. The shape element would be the ratio of bandwidths measured employing two distinctive attenuation values to determine the cutoff frequency, e. For passive bandpass filters for being crafted, all of that is needed http://erickspjcu.blogdon.net/the-single-best-strategy-to-use-for-narrow-bandpass-filter-13943025