Are there any simulators around to simulate ADS-B data (TIS-B & FIS-B)?
Aeroflex IFR-6000
From the manufacturer's website:

The Aeroflex IFR 6000 is a compact, lightweight and weatherproof unit designed for testing transponder modes A/C/S, TCAS I and II as well as DME. Includes antenna shield and hard transit case. The IFR 6000 features an extremely easy to use interface where every parameter the user commonly needs to view is displayed on screen.
Dedicated Mode keys for XPDR, DME and TCAS allow quick selection of the operational mode. The application dependent softkeys and data select/slew keys provide an intuitive man machine interface. DME mode is provided with dedicated keys for frequency/channel selection and RF level control.
For frequently varied parameters in DME and TCAS modes, such as Range and Rate, dedicated keys are provided. Each operational mode has one main user screen. The operational modes are: XPDR (Sub-Modes: ADS-B MON, ADS-B GEN &amp; GICB) DME TCAS 1, 2 (Sub-Modes: TIS) Most tests can be completed without leaving the main user screens. This simplifies the line technician's testing task.

However, it is subject to stringent export restrictions. If you are outside of the US, it is not available to you.