In a system or device, the ratio of (a) a specified maximum level of a parameter, such as power, current, voltage, or frequency to (b) the minimum detectable value of that parameter. Note: The dynamic range is usually expressed in dB. 2. In a transmission system, the ratio of (a) the overload level, i.e., the maximum signal power that the system can tolerate without distortion of the signal, to (b) the noise level of the system. Note: The dynamic range of transmission systems is usually expressed in dB. 3. In digital systems or devices, the ratio of maximum and minimum signal levels required to maintain a specified bit error ratio.