Another advantage of real-time generation is the ability to do closed-loop testing, which is of increasing importance in the latest digital wireless standards. Closed-loop testing is especially valuable in throughput testing of real-world channels. Two example configurations are shown in Figure 4. In testing such as LTE HARQ, the X-Series signal generators can receive TTL-level feedback signals and reconfigure the transmission signal while maintaining the link. This enables more realistic testing of throughput over impaired channels.
Deep arb memory and real-time signal generation in one unit
The replay of an arbitrary waveform file is often a better, simpler way to handle signal-simulation applications. In such cases, an important but simple technical advance is deep waveform memory: the MXG has up to 1 GSa and the EXG has up to 512 MSa. With 1 GSa, the MXG can provide a minimum of five seconds and as much as hours of continuous signal without repeating depending on sample rate—a capability that generally exceeds conformance requirements and can, in some cases, provide an alternative to real-time signal generation.
Watch the video to see how the X-Series signal generators reveal the true performance of devices: www.youtube.com/AgilentSigGen.