Why do digital modulation channels have measurable analog parameters?

Digital modulation channels indeed have measurable analog parameters because they involve the process of modulating an analog RF (radio frequency) carrier signal with digital data. This modulation process typically involves varying some aspect of the analog carrier, such as its amplitude, frequency, or phase, to represent the digital data being transmitted. Therefore, even though the data being transmitted is digital, the underlying carrier is an analog signal, allowing for measurable analog characteristics such as signal strength, quality, and noise levels.

The presence of these measurable analog parameters is crucial for ensuring effective transmission and reception of the digital information, as they can significantly affect the quality of the communication channel. Understanding these parameters is essential for analyzing and optimizing communication systems that operate on digital modulation techniques.

In contrast, other options do not accurately reflect the relationship between digital modulation and analog parameters. Digital carriers without analog components do not exist in this context, as the carrier must inherently possess analog traits for the modulation process to occur. Similarly, the assertion that it only operates in the digital domain overlooks the foundational role of the analog carrier signal. Lastly, while optical signals can play a role in certain digital communications, they do not represent the general principle of digital modulation channels concerning analog parameters.