The range of frequencies in which a signal contains power and information. The 3-dB bandwidth is the interval between frequencies at which the power spectral density has dropped to half power, or 3 dB below the peak value. Surface EMG signals typically contain energy at frequencies from 10 to 500 Hz. Intramuscular EMG signals contain energy at frequencies as high as 5 kHz (due to the rising edges of action potentials from muscle fibers close to the electrode). The bandwidth of the recorded signal may be altered by hardware or software filters applied to the signal.