The bandwidth of a band-pass filter is measured between what two frequencies?

The bandwidth of a band-pass filter specifies the width of the frequency range that can pass through the filter with minimal attenuation. By standard engineering convention, this is measured between the upper and lower 'half-power' points. At these half-power points, the signal voltage drops to 0.707 of its peak value, which corresponds to a power drop of exactly 3 decibels (-3 dB). Signals outside these two boundary frequencies are considered to be 'cut off' or rejected by the filter.