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The NI RF signal conditioning devices are designed to work with NI RF vector signal analyzers such as the NI PXI‑5660, NI PXI‑5661, and NI PXIe‑5663. NI RF signal conditioning devices are analog devices that amplify or attenuate their input signal according to the specified path and gain settings. No triggering scheme is required.
When using the NI RF signal conditioning devices with an NI RF vector signal analyzer, consider the following factors when determining the NI RF vector signal analyzer reference level setting.
For example, to obtain an input signal with a total integrated power of less than –30 dBm using a gain setting of 30 dB in the signal conditioning device, the proper NI RF vector signal analyzer reference level setting is 0 dBm.
Consider the following linearity factors when using NI RF signal conditioning devices.
Given an output third-order intercept (output TOI) specification, you can determine the intermodulation distortion (IMD) created by the RF amplifier or attenuator nonlinearity. For example, using a two-tone signal, the IMD is expressed by the following equation.
IMD (dBc) = 2 × [output fundamental tone level (dBm) – output TOI (dBm)]
For example, if the NI RF signal conditioning device output TOI at your frequency is +10 dBm, and your application requires better than –60 dBc of IMD, then your output fundamental tone level must be ≤–20 dBm. In this case, if gain is 30 dB, then the input fundamental tone level must be ≤–50 dBm.
Notes CH 1 main path linearity factors are as follows.