1. What is Noise Floor?

The noise floor represents the measure of the signal created from the sum of all the noise sources and unwanted signals within a measurement system. It sets the lower limit of the weakest signal that can be detected.

2. How Does the Calculator Work?

The calculator uses the noise floor equation:

Where:

• \( -174 \) — Thermal noise density at room temperature (dBm/Hz)
• \( \text{bandwidth} \) — System bandwidth in Hertz
• \( \text{noise\_figure} \) — Noise figure of the system in dB

Explanation: The equation accounts for the fundamental thermal noise plus the additional noise introduced by the system components.

3. Importance of Noise Floor Calculation

Details: Understanding the noise floor is crucial for designing communication systems, determining receiver sensitivity, and ensuring proper signal-to-noise ratios.

4. Using the Calculator

Tips: Enter bandwidth in Hertz and noise figure in dB. All values must be valid (bandwidth > 0, noise figure ≥ 0).

5. Frequently Asked Questions (FAQ)

Q1: Why is -174 dBm/Hz used as the base value?
A: This represents the thermal noise power density at room temperature (290K), which is a fundamental physical limit.

Q2: How does bandwidth affect noise floor?
A: Noise power increases with bandwidth - doubling the bandwidth increases noise floor by 3 dB.

Q3: What's a typical noise figure for receivers?
A: Good receivers typically have noise figures between 1-5 dB, though this varies by application and frequency.

Q4: Can noise floor be lower than -174 dBm/Hz?
A: No, this represents the fundamental thermal noise limit at standard temperature.

Q5: How is this different from SNR?
A: Noise floor sets the lower limit, while SNR compares signal power to noise power at a specific point.