National Instruments 779465-01 PXI RF Amplifier 

National Instruments part number 779465-01 is an identifying part number for the PXI-5690, a PXI RF Amplifier with 2 channels, 3 GHz programmable module with fixed and configurable gain. The NI 779465-01 allows users to bypass its gain by switching to a direct path programmatically. This capability enhances the testing and monitoring performance of PXI RF Vector Signal Analyzers by allowing the adjustment of dynamic range to effectively monitor signals ranging from very weak to very strong. It is designed for use with RF vector signal analyzers, such as the NI PXI-5660. 

It functions as a straightforward device that either amplifies or attenuates its input signal based on the selected path and gain settings, with no triggering scheme required. In this model, Channel 0 (CH 0) operates as a fixed gain preamplifier with a gain of 30 dB. This channel features a low noise figure and a flat frequency response, allowing users to utilize CH 0 similarly to a conventional fixed gain preamplifier. Conversely, Channel 1 (CH 1) functions as a programmable preamplifier with two user-selectable paths. 

On the 779465-01, the primary path includes fixed gain amplification followed by a step attenuator, adjustable in 1 dB increments via software according to the user-defined gain settings. The output gain range for this path is from -10 to +20 dB. 

The direct path provides an option to bypass the attenuator-amplifier hardware, which is useful for handling higher power inputs that could potentially cause distortion in the RF preamplifier. This device weighs 9.2 oz and measures 8.5 x 0.8 x 5.1 inches in dimensions.