What does modulation of the video signal primarily change in a controlled manner?

The modulation of the video signal primarily involves changing the amplitude of the signal in a controlled manner. In video systems, this often refers to how the brightness levels of the image are affected. When the amplitude is modulated, it directly translates to variations in the intensity of the displayed image on the screen.

While frequency can also play a role in video signals, modulation typically refers to adjustments in amplitude to control signal strength and, consequently, the visual output's brightness. Understanding this aspect of video modulation is vital for operations in fluoroscopy, where controlling image clarity and brightness is essential for accurate diagnoses and observations.

In summary, the modulation of the video signal is crucial for achieving the desired visual presentation, particularly through the controlled changes in intensity by manipulating the amplitude of the signal.