📡 RF Interference & SNR Analyzer

🎯 What is Signal-to-Noise Ratio (SNR)?

SNR measures the quality of a signal by comparing the desired signal power to the unwanted noise power. Higher SNR means clearer communication.

$\text{SNR (dB)} = 10 \log_{10}\left(\frac{P_{signal}}{P_{noise}}\right)$

Where:

• $P_{signal}$: Desired signal power (watts, mW, dBm, etc.)
• $P_{noise}$: Total noise power (thermal noise + interference)
• SNR > 20 dB: Excellent signal quality
• SNR 10-20 dB: Good quality, minor degradation
• SNR 0-10 dB: Poor quality, significant errors
• SNR < 0 dB: Noise exceeds signal—unusable

⚡ Types of Interference

• Thermal Noise: Random noise from molecular motion in conductors (always present)
• Crosstalk: Unwanted coupling between adjacent signal paths (cables, PCB traces)
• EMI (Electromagnetic Interference): External noise from motors, switching power supplies, RF transmitters
• Adjacent Channel Interference: Signals from nearby frequency channels bleeding into your signal

🛡️ Shielding Effectiveness

Different shielding materials reduce EMI by different amounts:

• No Shielding: 0 dB reduction (baseline)
• Aluminum Foil: 20-40 dB reduction (low-cost, effective for high frequencies)
• Copper Mesh: 40-60 dB reduction (better conductivity than aluminum)
• Steel Enclosure: 60-80 dB reduction (good for magnetic shielding)
• Mu-Metal: 80-100 dB reduction (premium, best for low-frequency magnetic fields)

📐 Real-World Applications

• WiFi (2.4 GHz): Typical SNR 25-40 dB in good conditions
• Cellular (LTE/5G): Minimum 0-5 dB, excellent >15 dB
• Instrumentation: High-precision systems need SNR > 60 dB
• Audio Systems: CD quality requires SNR > 96 dB
• Satellite Communications: Often operates near 0 dB (advanced error correction)