National Instruments 781431-01 Signal Downconverter Module 

National Instruments part number 781431-01 is an identifying part number for the PXIe-5605, an RF Signal Downconverter Module with SMA Female Connector and AC/DC Coupling. This Downconverter Module is known for its precision and exceptional performance, featuring a broad frequency range from 20 Hz to 14 GHz and automated testing capabilities. This module is an integral part of the PXIe-5665 RF Vector Signal Analyzer, working alongside the PXIe-5653 Analog Signal Generator and PXIe-5622 IF Digitizer. 

The 781431-01 provides an impressive average noise level of -165 dBm/Hz at a 1 GHz carrier frequency and a phase noise of -129 dBc/Hz. Users can utilize NI-RFSA for automatic IF filter control, with an option for manual filter selection. This device supports three types of IF bandpass filters: 5 MHz, 300 kHz, and Through. The Through bandpass filter, at -6 dB, offers a nominal bandwidth of 80 MHz. With the pre-selector enabled, it functions at a typical bandwidth of 47 MHz. The 5 MHz filter provides a nominal bandwidth of 5 MHz at -3 dB, with an output IF frequency of 190 MHz. 

The 300 kHz filter offers a nominal IF output frequency of 199 MHz at -3 dB. The National Instruments 781431-01 Downconverter Module features several connectors: one RF IN, one IF OUT, one LO1 IN, one LO2 IN, one LO3 IN, and three LO OUT connectors (LO1 OUT, LO2 OUT, LO3 OUT). This module includes an external DC block, compatible with an SMA DC block, which is utilized at the RF IN connector to protect the device when a DC signal is present.