Digital communications systems are rapidly evolving today, calling for test equipment that can meet the new challenges they present. An important component of such test equipment is a flexible baseband source that allows development and production tests to be performed on state-of-theart receivers for a variety of standards. A self-contained baseband source must fulfill a wide range of signal requirements. Plus, it needs variable digital and analog outputs in order to directly operate the DUT. Used as a modulation source for vector signal generators, the R&S® AFQ100A provides I/Q signals that offer all the sophistication of modern communications standards for generating the required RF signal. Featuring a maximum clock rate of 300 MHz and a waveform memory of up to 1 Gsample, the new R&S® AFQ100A generator provides unprecedented functionality and offers precisely the flexibility that is required. It allows long sequences to be generated for bit error ratio measurements; moreover, its high clock rate provides the necessary bandwidth for supporting future broadband communications systems. Especially in the case of very broadband applications, modules such as I/Q modulators produce a nonlinear frequency response. To compensate for this effect, the R&S® AFQ100A is equipped with an equalizer that linearizes the entire frequency response in realtime. The R&S® AFQ100A combines flexibility with outstanding signal quality. Its spurious suppression, for example, is first-rate, and its frequency response extremely linear. All these basic features combined with a host of other functions make the R&S® AFQ100A a versatile baseband generator that can easily be adapted to changes.