Which measurement reflects the maximum range of signal intensities a digital system can represent?

The measurement that reflects the maximum range of signal intensities a digital system can represent is bit depth. Bit depth indicates the number of bits used to represent each pixel's color or intensity in a digital image. For instance, in an 8-bit system, there are 256 possible values (2^8) for each pixel, allowing for a range of intensity levels from 0 to 255. Consequently, a higher bit depth enables a greater range of signal intensities, improving image quality by allowing for smoother gradients and less banding in areas of subtle color transitions.

Dynamic range is often confused with bit depth, but it specifically refers to the ratio between the largest and smallest values a system can capture, primarily related to exposure levels, rather than the discrete values used to represent each intensity. Pixel depth and spatial frequency pertain to different aspects of digital imagery and its representation, with pixel depth relating to the dimension of the image in terms of pixels and spatial frequency addressing the detail in the image structure, notably concerning how fine the details are that can be distinguished.

Overall, bit depth is crucial as it defines the granularity and range of tones available in digital images, thus essential for effective digital radiography.