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Equivalent input voltage noise density can be calculated with the following equation:

**Figure 1**. Equation

For example, 50uV noise at 400kHz bandwidth would have an 80nV/root Hz equivalent voltage noise density:

**Figure 2**. Equation example

### Additional Information

Other mathematical equation and explanation related to frequency domain, you can find in

The Fundamentals of FFT-Based Signal Analysis and Measurement in LabVIEW and LabWindows/CVI.