The ThinkRF Real Time Spectrum Analyzer R5500/R5550 comes integrated with external GPIOs, I and Q output ports, among others.
The external GPIOs consist of the external trigger feature, enabling synchronized sweep setup to automate spectrum scanning and capture with the use of external hardware and/or multiple ThinkRF RTSA devices. Meanwhile, the I and Q output ports facilitate integration with external high speed digitizers.
This application note explains how to setup a synchronized sweep with signals feed to external I and Q output ports, as well as providing the GPIO setup requirement.