The Wideband Test Modulator – Singlerate (WTM-SR) generates an OQPSK signal. Currently the data rate is 320 Mb/s. Both single ended and two cable differential ECL inputs are provided on the rear panel. Input selection is via the front panel or remote interface. Output amplitude selection and status are provided both locally and remotely. The test modulator is typically used for prepass satellite earth station setup or for performance testing.