The ADS-B live consists of both, hardware and software.
The product consists of an antenna, a DSP, and a handling software. It is installed on a rack server.
ADS-B provides uplink and downlink info.
The downlink pulses are based on live signals measured with the antenna.
The uplink signals (interrogation in Mode A, C and S) are synthetically generated and added, as it is forbidden by law to send interrogation signals (generated for training purposes) into the sky.
Learn more about the ADS-B live radar here.