High frequency signal using low frequency micro-controller
The 2.4 GHz carrier for the radio is generated with a dedicated voltage controlled oscillator. This oscillator will be locked to a low frequency reference with a PLL for stability. The data to be transmitted is not actually sent at 2.4 GHz - it gets generated by a digital to analog converter at several MSa/s. A mixer will be used to translate the output of the DAC up to the required RF channel frequency. There will also be dedicated signal processing logic that translates the actual packet data into baseband modulated samples that get sent to the DAC. The processor only provides the packet data to the beginning of the transmit chain, the rest of it is handled in dedicated digital and analog hardware. The receive chain will be similar to the transmit chain, except operating in the other direction and with a few additional components for tracking the carrier.