The way it works for power over Ethernet — and I assume USB power delivery must work the same way — is that it does not reduce bandwidth because they run the power and the signal over the same wires at the same time.
There is a a power injector at one end and a filter at the other end that separate out the high-frequency signal and the DC (no-frequency) power into different wires.
This is essentially the same thing as they’re already doing for multi-frequency stacking on those same wires (and on fiber) to get the crazy bandwidth in the first place. DC power is just one more low (very very low) frequency running on the same stack.
The way it works for power over Ethernet — and I assume USB power delivery must work the same way — is that it does not reduce bandwidth because they run the power and the signal over the same wires at the same time.
There is a a power injector at one end and a filter at the other end that separate out the high-frequency signal and the DC (no-frequency) power into different wires.
This is essentially the same thing as they’re already doing for multi-frequency stacking on those same wires (and on fiber) to get the crazy bandwidth in the first place. DC power is just one more low (very very low) frequency running on the same stack.