Why do most broadband cable networks use analog modulation downstream instead of digital modulation?

In broadband cable networks, utilizing analog modulation downstream predominantly stems from its lower complexity in terms of signal processing requirements. Analog modulation allows for a simpler architecture, reducing the need for extensive digital signal processing equipment. This can lead to cost savings and a more straightforward implementation, particularly in legacy systems where existing infrastructure may still prioritize analog methods for compatibility and ease of integration.

While it's true that there are advantages to digital modulation, including greater flexibility and robustness to interference, the historical context and established technology of many broadband cable networks have made analog modulation a practical choice. Therefore, the requirement for minimal incoming signal processing is a key factor driving the preference for analog methods in these systems.