In a system providing video-on-demand services, what determines the data input to the QAM modulator?

In video-on-demand services, the data input to the QAM (Quadrature Amplitude Modulation) modulator is primarily influenced by the volume of content being served to viewers. This volume can be represented by the number of orders being fulfilled, which is directly linked to the user requests for specific videos at any given time. When multiple users access different videos concurrently, the system needs to manage and modulate this data effectively to ensure smooth delivery.

The other factors, such as the number of subscribers or the time of day, might influence overall traffic patterns but do not directly determine the immediate data input to the modulator at any specific instance. Available bandwidth is also crucial as it dictates the maximum data that can be processed, but it doesn’t directly guide the specific input to the modulator in terms of current user requests. Thus, the most accurate measure of what dictates the data input to the QAM modulator is indeed the number of orders being fulfilled actively at that moment.