1. What is Resolution Bandwidth?

Resolution Bandwidth (RBW) is the frequency resolution of a spectrum analyzer or FFT-based measurement system. It determines the smallest frequency difference that can be distinguished between two signals.

2. How Does the Calculator Work?

The calculator uses the RBW equation:

Where:

• Sample Rate — The sampling frequency of the system (Hz)
• FFT Size — The number of points in the Fast Fourier Transform

Explanation: The RBW is inversely proportional to the FFT size - larger FFT sizes provide better frequency resolution.

3. Importance of RBW Calculation

Details: Proper RBW setting is crucial for accurate spectral measurements. Too wide RBW may miss closely spaced signals, while too narrow RBW increases measurement time unnecessarily.

4. Using the Calculator

Tips: Enter sample rate in Hz and FFT size in points. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: How does RBW affect measurement time?
A: Narrower RBW requires longer measurement times as more samples are needed for the same frequency span.

Q2: What's the relationship between RBW and frequency resolution?
A: RBW directly determines the frequency resolution - smaller RBW means better ability to distinguish closely spaced frequencies.

Q3: How do I choose appropriate FFT size?
A: Choose based on required frequency resolution (RBW) and available processing power/memory. Larger FFT sizes provide better resolution but require more computation.

Q4: Does windowing affect RBW?
A: Windowing increases the effective RBW by a factor (window bandwidth factor) specific to the window type used.

Q5: What's typical RBW for common applications?
A: Audio analysis might use 1-10 Hz RBW, RF measurements typically use 1 kHz-1 MHz RBW depending on application.