The National Instruments PXI-5661 is a modular 2.7 GHz RF vector signal analyzer with wide real-time bandwidth, optimized for automated test in a compact, 3U PXI package. It is suitable for high-throughput RF acquisition and measurements. The 20 MHz wide onboard quadrature digital downconverter (DDC) significantly reduces the required load size and the time needed to transfer waveform data to the host controller or PC. This functionality is suitable for engineers who require data streaming with rapid response time for software-defined radio (SDR), real-time signal processing, or faster transfer times for spectral monitoring applications. The module is also compatible with Conduant StreamStor devices, enabling terabyte recording. The NI PXI-5661 RF analyzer also includes a burst power trigger suitable for communications applications and signal intelligence. The PXI-5661 features a highly stable timebase and flexible software tools, including Express VIs for National Instruments LabVIEW. The NI Spectral Measurements Toolkit for LabVIEW and LabWindows/CVI accompanies the PXI-5661, providing common measurements such as power spectrum, peak power and frequency, in-band power, adjacent-channel power, and occupied bandwidth. Additionally, it offers vector capabilities, such as 3D spectrograms, I/Q data for modulation analysis, and analog modulation analysis functions for LabVIEW.