Dynamic range:
1. 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.
Source: from Federal Standard 1037C and from MIL-STD-188
