Configure your vibration analyzer data acquisition settings. Calculate frequency resolution from sampling parameters, or work backwards from a target resolution to determine the minimum sampling rate and record length needed.
Forward: Settings → Resolution
Reverse: Resolution → Settings
Results
Why FFT Resolution Matters
Frequency resolution (Δf = fs/N) determines whether you can distinguish between closely-spaced frequencies in a vibration spectrum. For bearing analysis, you need sufficient resolution to separate defect frequencies (BPFO, BPFI, BSF, FTF) from shaft harmonics and other mechanical frequencies.
Window Functions
Windowing reduces spectral leakage but widens spectral peaks, effectively reducing your usable frequency resolution. The Hanning window is the most common choice for vibration analysis, providing a good balance between leakage reduction and resolution.
Practical Tips
- Use our Bearing Defect Frequency Calculator to determine the exact frequencies you need to resolve.
- FFT is most efficient when N is a power of 2 (1024, 2048, 4096, 8192, etc.).
- The recommended sampling rate is 2.56× the maximum frequency of interest (not just 2×) to allow for anti-aliasing filter roll-off.