Abstract: An arrangement (30) and a method for digitally filtering a time-discrete digital signal, wherein the signal is transformed to the frequency domain using discrete Fourier transformation (31), the signal is filtered in the frequency domain (33), wherein a filter response can be adapted in real time as required to respond to changes in the interference environment, and the filtered signal is transformed back to the time domain using inverse discrete Fourier transformation (32) to create an output signal, and wherein bin frequencies of said signal in the frequency domain are translated by a real amount and the sampling rate of the output signal is changed by a real factor.

Abstract: A high-performance software tool for testing networks, having many new features. First, the test tool combines both control traffic and data traffic generation in one platform. Existing tools do only one or the other. Second, by dynamically linking protocol stacks, the test tool achieves stunning performance levels. More than 1,000 new sessions per second per test server. More than 200,000 simultaneous sessions per test server. Modeling real-world traffic requires these speeds. Third, even at these speeds, each session simulates real-world user activities with “stateful,” meaningful data. Fourth, the test tool has a “software only” architecture. No special hardware needed. The tool runs on any platform from a laptop to a system with 32 (or even more) “off the shelf” test servers. That reduces system cost and makes it easy to scale to high capacities. It also makes the test tool much easier to modify and update than existing tools.