In your radio profiles you can change the mode of your APs to one of the following: am-mode, ap-mode, spectrum-mode (hybrid mode). am-mode = air monitor, doesn't serve clients. ap-mode = standard ap. spectrum-mode = spectrum monitoring. If you select ap-mode, you there will be a check box to enable Spectrum Monitoring. The AP will operate in hybrid mode, serving clients and performing spectrum monitoring simultaneously.
CLI example:
rf dot11a-radio-profile "dot11a_radio_profile"
mode ap-mode
spectrum-monitoring
Chapter 34 of the Aruba OS User Guide talks about Spectrum Analysis.