Signal-to-Noise Ratio Calculator
Power-Based Formulas:
Linear SNR: \( SNR = \frac{P_{signal}}{P_{noise}} \)
SNR in dB: \( SNR_{dB} = 10 \log_{10} \left( \frac{P_{signal}}{P_{noise}} \right) \)
Voltage-Based Formula:
SNR in dB: \( SNR_{dB} = 20 \log_{10} \left( \frac{V_{signal}}{V_{noise}} \right) \)
SNR Results
Linear SNR:
-
SNR in dB:
-
Interpretation:
Enter values to calculate SNR
Help Guide
What is SNR?
The Signal-to-Noise Ratio (SNR) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. It is defined as the ratio of signal power to the noise power, often expressed in decibels (dB).
Why is SNR Important?
SNR is a key parameter in many fields including:
- Audio Engineering: Higher SNR means cleaner audio with less background noise
- Telecommunications: Affects the quality and reliability of signal transmission
- Electronics: Helps in designing circuits with optimal performance
- Image Processing: Determines image quality in digital cameras and medical imaging
Interpretation of SNR Values
| SNR (dB) | Interpretation |
|---|---|
| > 30 dB | Excellent signal quality |
| 20-30 dB | Good signal quality |
| 10-20 dB | Fair signal quality |
| 0-10 dB | Poor signal quality |
| < 0 dB | Noise dominates the signal |
Calculation Methods
Power-Based Calculation
When you know the signal and noise power levels:
Linear SNR: \( SNR = \frac{P_{signal}}{P_{noise}} \)
SNR in dB: \( SNR_{dB} = 10 \log_{10} \left( \frac{P_{signal}}{P_{noise}} \right) \)
Voltage-Based Calculation
When you know the signal and noise voltage levels (assuming same impedance):
SNR in dB: \( SNR_{dB} = 20 \log_{10} \left( \frac{V_{signal}}{V_{noise}} \right) \)
Note: The factor of 20 comes from the square relationship between power and voltage (P = V²/R).
Practical Examples
Example 1: Audio System
Scenario: An audio amplifier outputs a signal with 50W power, but has a noise floor of 5mW.
Calculation:
- Convert noise power to watts: 5mW = 0.005W
- Linear SNR = 50W / 0.005W = 10,000
- SNR in dB = 10 × log₁₀(10,000) = 40 dB
Interpretation: This is an excellent SNR for an audio system, indicating very clean sound with minimal noise.
Example 2: Wireless Communication
Scenario: A WiFi receiver measures signal voltage of 2mV and noise voltage of 500µV.
Calculation:
- Convert to same units: 500µV = 0.5mV
- SNR in dB = 20 × log₁₀(2mV / 0.5mV) = 20 × log₁₀(4) ≈ 12.04 dB
Interpretation: This is a fair SNR for wireless communication, which might result in some packet loss or reduced data rates.
Example 3: Sensor Measurement
Scenario: A temperature sensor outputs 1.2V signal with 0.3V noise.
Calculation:
- SNR in dB = 20 × log₁₀(1.2V / 0.3V) = 20 × log₁₀(4) ≈ 12.04 dB
- Linear SNR = 1.2V / 0.3V = 4
Interpretation: This low SNR suggests the sensor readings may be unreliable, and signal conditioning or averaging might be needed.
Quick Tips
- Always ensure signal and noise measurements are in the same units before calculation
- For voltage measurements, both signals must be measured across the same impedance
- In practice, aim for SNR > 20dB for most applications
- Remember that 6dB increase represents a doubling of the voltage ratio or quadrupling of power ratio
About SNR Calculator
Tool Description
The Signal-to-Noise Ratio (SNR) Calculator is a web-based tool designed to help engineers, students, and professionals quickly calculate and understand SNR values in both linear and logarithmic (decibel) scales.
Features
- Calculate SNR from power or voltage measurements
- Support for multiple units (W, mW, µW, V, mV, µV)
- Automatic unit conversion and calculation
- Graphical representation of signal vs noise
- Export results to PDF or CSV
- Comprehensive help guide with examples
- Responsive design works on all devices
- Dark/Light mode support
Formulas Used
Power-Based SNR:
Linear: \( SNR = \frac{P_{signal}}{P_{noise}} \)
Decibel: \( SNR_{dB} = 10 \log_{10} \left( \frac{P_{signal}}{P_{noise}} \right) \)
Voltage-Based SNR:
Decibel: \( SNR_{dB} = 20 \log_{10} \left( \frac{V_{signal}}{V_{noise}} \right) \)
Version: 1.0.0
Last Updated: June 2023