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Signal-to-Noise Ratio (SNR)

Calculate the ratio of desired signal power to background noise power. Supports both decibel and ratio modes for audio, RF, and scientific applications.

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Applications

Used by RF and telecommunications engineers evaluating receiver sensitivity and link budgets, audio engineers assessing microphone noise floors and amplifier headroom, instrumentation specialists measuring sensor precision and ADC resolution, and data analysts evaluating signal quality in spectroscopy and low-amplitude measurement contexts.

The Formula

In decibel mode: SNR (dB) = Signal (dB) - Noise (dB). In power ratio mode: SNR (dB) = 10 * log10(Signal / Noise). In voltage ratio mode: SNR (dB) = 20 * log10(V_signal / V_noise) - because power is proportional to voltage squared, the 20log10 form applies when inputs are voltages. SNR ratio (linear) is then 10^(SNR_dB / 10) for power or 10^(SNR_dB / 20) for voltage.

Fun Fact: A high-fidelity audio CD uses a 96 dB SNR, FM stereo broadcast needs at least 50 dB to sound clean, and the Voyager 1 spacecraft - now in interstellar space - maintains a usable signal at around 22 billion kilometers from Earth with a link budget that survives a noise floor only its antennas could overcome.

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