The PA 2522 is used to amplify measurement signals, e.g. weak signals from high-resolution near-field probes. The PA 2522 is connected to the 50 Ω input of a spectrum analyzer or oscilloscope and supplied via the plug-in power supply unit. A near-field probe can be connected to the input of the preamplifier using an appropriate cable. The input and output of the PA 2522 are designed as SMA connectors.