Solving the Cable TV Infrastructure Downstream Transmitter Challenge
Driven by demand for faster internet connectivity, the cable TV industry has developed new network architectures for the delivery of multigigabit services to subscribers. This fiber deep approach, using a remote PHY device (RPD), moves critical hardware closer to the users by using digital fiber.
This is comparable with a remote radio head in wireless (cellular) networks and while this saves space and reduces heat dissipation in the headend, it creates new design challenges for remote equipment.
Although lower in absolute frequency, cable TV signals have much wider bandwidths than wireless, extending across several octaves from 108 MHz to 1218 MHz, with multiple in-band harmonics. RPDs have created a perfect storm for designers, where the RF and mixed-signal hardware must cover a wider frequency range, with higher RF powers, lower noise floor, and better linearity, while consuming less dc power. The downstream f