Hi, @Annie_he
As my understanding, the modulation and demodulation is implemented by physical layer, not by HCI layer.
HCI layer is only a middle layer to transfer commands from host to controller and transfer events from controller to host, or transfer data from both side. It means, for HCI layer, there is no relationship with modulation or demodulation.
Can you please let me know why do you need this kind of HCI cmd to send UModulation siganl? Or provide me more details about your using cases?
Best regards,
Christine.