(V) The SI unit of electric potential.
Definition: The amount of potential energy present per unit of charge. 1 volt representing a potential of 1 joule per coulomb of charge.
The unit is named for the Italian scientist Count Alessandro Volta.

Process of conversion of continuous (analog) signals, such as the detected MR signal (voltage), into numbers. This is carried out with an analog to digital converter. There are two kinds of discretization involved: the voltage is only measured (sampled) at particular discrete times, and only voltages within a particular range and separated by a particular minimum amount can be distinguished. Voltages beyond this range are said to exceed the dynamic range of the digitizer.

The electromagnetic signal in the radio-frequency range produced by the precession of the transverse magnetization of the spins. The rotation of the transverse magnetization induces a voltage in a receiving antenna (coil), which is amplified and demodulated by the receiver circuits. Electromagnetic signal in the radio frequency range produced by the precession of the transverse magnetization of the spins. The rotation of the transverse magnetization induces a voltage in a coil, which is amplified and demodulated by the receiver;; the signal may refer only to this induced voltage.

(A or amp) The SI base unit of electric current.
Definition: Two parallel conductors, infinitely long and having negligible cross section, should be placed 1 meter apart in a perfect vacuum. One ampere is the current that creates between them a force of 0.2 micronewton per meter of length.
One ampere represents a current flow of 1 coulomb of charge per second.
One ampere of current results from a potential distribution of 1 volt per ohm of resistance, or from a power production rate of 1 watt per volt of potential.
The unit is known informally as the amp, but A is its official symbol and is named for the French physicist André-Marie Ampère.

Quick Overview
Please note that there are different common names for this artifact.

Noise introduced into digitized signals by the finite voltage resolution of the digitizer.
You can see the effects of quantization if the noise level is smaller than the digitizer quantum. If the signal dynamic range is too great, the highest intensities from overloading the digitizer may result in the weaker features being lost in the digitization noise.

This can be resolved by using an analog to digital converter with a larger range of sensitivity or by using techniques to reduce the dynamic range, e.g. suppressing the signal from water in order to detect the signal from less abundant compounds.