A processor for a radio circuit is disclosed. The processor includes a full spectrum receiver and a white space classifier. The full spectrum receiver is configured to receive an analogue radio signal comprising multiple channels within a frequency band and transform the analogue radio signal to a digital radio signal. The full spectrum receiver is also configured to transform the digital radio signal from a time domain signal to a frequency domain signal. The white space classifier is configured to identify an unused channel within the frequency band using the frequency domain signal derived from the analogue radio signal.