Understanding RF concepts and the concepts that underpin NI's RF hardware will help you be successful with your instrument.

Carrier Wave
The carrier wave is a sinusoidal wave that is modulated by a message signal, m(t), prior to transmission.
Message Signal
The message signal contains the data for transmission.
Modulation
Modulation is a process that alters the characteristics of a carrier wave according to information in the message signal to generate and transmit a modulated wave. There are several different types of modulation.
I/Q Modulation
I/Q is a common way to represent message signals in modern communication systems.
Quadrature Mixing (Direct Conversion)
Quadrature mixing allows for the complex modulation or demodulation of signals as represented by two orthogonal signals I and Q. Quadrature mixing has the added benefit of an increased complex bandwidth that allows for net bandwidths up to the sample rate of the DACs.
Sample Rate
Sample rate is the rate at which digital data is transferred from the memory to the digital-to-analog converter (DAC).
Impedance Matching
When broadband signals are carried on transmission lines of any significant length, the presence of impedance discontinuities or mismatches degrade the amplitude and phase accuracy, as well as the temporal fidelity, of waveforms generated with a signal generator. To minimize signal reflections, the source and load impedances should equal the characteristic impedance of the transmission line.
Resolution Bandwidth
For NI VSAs and VSTs, the resolution bandwidth (RBW) determines the fast-Fourier transform (FFT) bin size, or the smallest frequency that can be resolved.
Noise Fundamentals
There are multiple types of noise to consider when analyzing RF signals.
Average Power and Crest Factor Considerations
Crest factor is the difference between peak signal power and average power.
Streaming
Streaming is a way to generate waveforms that are too large to fit in the onboard memory of an RF signal generator.
Scripts
You can link and loop multiple waveforms together in a generation operation using a script. A script is a series of instructions that indicates how waveforms saved in the onboard memory should be sent to the DUT.
How Signal Routing Works
NI VSTs are capable of sending and receiving signals through the front panel connectors and the PXI trigger bus. Signals are routed between a source and destination via a path through the PXI trigger bus; there are two broad categories of routes.
Triggers and Events
You can use triggers and events to coordinate the operation of multiple channels and instruments.

PXIe-5831 User Manual

44 GHz, 1 GHz Bandwidth PXI Vector Signal Transceiver

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