Why do values expressed in dBmV progress in a nonlinear fashion compared to a linear mV scale?

The correct answer is based on the fact that dBmV represents a logarithmic scale, which is fundamentally different from a linear scale like millivolts (mV). When dealing with electrical signals, power levels can vary significantly, and logarithmic scales are often used to compress this wide range of values into a more manageable form.

Specifically, dBmV denotes the power level relative to one millivolt, using base 10 logarithms to express that relationship. This means that each increase in 1 dBmV corresponds not to a simple additive increase in voltage but to a multiplicative increase in power. As a result, the progression of dBmV values reflects the exponential nature of power ratios, leading to a nonlinear representation when mapping those values compared to a straightforward linear mV scale.

This logarithmic relationship is particularly useful in telecommunications and signal processing, where it provides a clearer way to visualize and work with very large or very small power levels, enabling easier comparison of signal strengths. Hence, the characteristic of nonlinearity in progression of dBmV effectively allows for better handling of a wide range of voltage levels.