The Keysight 8515A S-parameter test set is available for the Keysight 8510C network analyzer for broadband coaxial measurements from 45 MHz to 50 GHz. The Keysight 8515A test set has an architecture that develops a separate reference channel for each incident port. RF switching is done with a built-in electronic switch. For active device measurements, the test set includes the ability to apply dc bias (external) to the test port center conductors. Also available are two 90 dB step attenuators, which allow control of the port 1 and port 2 signal levels.