a) The range of frequencies which a piece of equipment can process. b) A system’s ability to uniformly transfer signal components of different frequencies without affecting their amplitudes. This parameter is also known as gain/frequency distortion or amplitude versus frequency response. The amplitude variation maybe expressed in dB, percent, or IRE. The reference amplitude (0 dB, 100%) is typically the white bar or some low frequency. Frequency response numbers are only meaningful if they contain three pieces of information: the measured amplitude, the frequency at which the measurement was made, and the reference frequency.

There are a number of test signals that can be used to evaluate frequency response. They include Multiburst, Multipulse, a swept signal, or (Sin X)/X.