Agilent N4903A is a state of the art bit error rate tester for baseband data signals in the range 150 Mb/s to 7 Gb/s. N4903A allows for measurement of jitter in the received signal and, at the same time, measures the robustness of a connected device to jitter according to standard masks (e.g. for Fibre Channel, 10 Gb Ethernet and other). Random or deterministic jitter can be added for testing purposes and inter-symbol interferences can be simulated. The instrument can display the eye diagram as well as jitter spectrum.