A measurement of the difference in cycles/sec between the limiting frequencies of a band in which the attenuation of any frequency, with respect to the central frequency, isless than a specified value(usually half power or three db).

• 一个频带的上下界频率之间差的一种度量，以周期/秒表示。在该频带中，任何一频率的衰减（对中心频率而言）小于一个特定的值（通常为半功率或3分贝）。