To equate continuous wave with a digital clock running at 2 GHz, you have to consider how many harmonics of the base frequency are needed to construct the digital pulse. Normally at least 5 harmonics of the original frequency need to be considered. So for 2 GHz this represents a continuous wave frequency of 10 GHz. So to pass 2 GHz digital pulses in a circuit it would need to have a frequency response of 10 GHz.
