Glossary definition of SNR

Also known as: Signal to Noise Ratio, S / N

Signal to Noise Ratio (SNR or S / N) is a measure of the strength of a wanted signal relative to the amount of background noise. SNR is usually given in decibels (dB), a logarithmic measurement that scales the signals in a similar way to human hearing.

SNR may refer to audio as well as RF signals, and the term is often used in the specification of communication systems. It should be noted that SNR could be quoted in two forms: either for peak-to-peak levels (i.e. worst case), or as an average rms (root mean square) value.

Generally, the higher the SNR the better will be the quality of the phone communication. In contrast, when transmission / reception conditions are poor between the mobile and its base station, the SNR will decrease and noise interference will make communication more difficult. If the SNR is very low, for example in the region of zero to 3dB, then the signal may become unintelligible or data speed may be reduced due to frequent errors. Increasing output powers or improving the performance of the transmitter and receiver antennas will improve the SNR ratio.