Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Signal-to-noise ratio
open-in-new
<p>Signal-to-noise ratio (SNR or S/N) is a measure used in <a href="/facts/Science_and_engineering/RFVg8H3I">science and engineering</a> that compares the level of a desired <a href="/facts/Signal/41YqUJ8c">signal</a> to the level of background <a href="/facts/Noise_(signal_processing)/JT3lGj8v">noise</a>. SNR is defined as the ratio of signal <a href="/facts/Power_(physics)/mkaEyRnn">power</a> to <a href="/facts/Noise_power/orFSKhF4">noise power</a>, often expressed in <a href="/facts/Decibel/0LyxAPXh">decibels</a>. A ratio higher than 1:1 (greater than 0 dB) indicates more signal than noise. </p><p>SNR is an important parameter that affects the performance and quality of systems that process or transmit signals, such as <a href="/facts/Communication_system/5t3Ys2DI">communication systems</a>, <a href="/facts/Audio_system/BMbpAWkE">audio systems</a>, <a href="/facts/Radar_system/jk9BTbFA">radar systems</a>, <a href="/facts/Imaging_system/Lkw7V9M8">imaging systems</a>, and <a href="/facts/Data_acquisition/W7d5DrPl">data acquisition</a> systems. A high SNR means that the signal is clear and easy to detect or interpret, while a low SNR means that the signal is corrupted or obscured by noise and may be difficult to distinguish or recover. SNR can be improved by various methods, such as increasing the signal strength, reducing the noise level, filtering out unwanted noise, or using error correction techniques. </p><p>SNR also determines the maximum possible amount of data that can be transmitted reliably over a given channel, which depends on its bandwidth and SNR. This relationship is described by the <a href="/facts/Shannon%25E2%2580%2593Hartley_theorem/nlWW6VAy">Shannon–Hartley theorem</a>, which is a fundamental law of information theory. </p><p>SNR can be calculated using different formulas depending on how the signal and noise are measured and defined. The most common way to express SNR is in decibels, which is a logarithmic scale that makes it easier to compare large or small values. Other definitions of SNR may use different factors or bases for the logarithm, depending on the context and application. </p>