The NI PXIe-5661 from National Instruments Corporation is a RF Spectrum Analyzer with Frequency 9 kHz to 2.7 GHz, Resolution Bandwidth 20 MHz, DANL -122 dBm/Hz, Dynamic Range 80 dB, Phase Noise -90 dBc/Hz. Tags: PXI. More details for NI PXIe-5661 can be seen below.