How is Signal to Noise Ratio Expressed?

Signal to noise ratio is written as a ratio of the strength of the signal output as compared to background noise measured in decibels (dB). The larger the number, the higher the signal or audio quality or specification. For example, a SNR of 80 dB is considered to be of higher quality than one of 50dB. If the SNR is negative, then the signal or audio source may be verging on not being useful for its intended purpose. Typically, these cases indicate a new source of noise to the audio system or a failed component which requires additional troubleshooting and/or repair work to be accomplished.

Why Is Signal to Noise Ratio Important?

All electrical components will suffer from some level of ambient noise when outputting audio or other electrical related signals. For the majority of consumers, SNR starts to become an issue as additional components are added to home or car stereo systems such as DVD/CD players, amplifiers, an additional speakers. Digital components have been found to have a higher SNR than analog ones and have been shown to support a greater ability to be tied together in complex entertainment centers without significantly degrading audio or video quality. In recent years, consumers have also been exposed to SNR ratios when setting up home DSL connections for Internet connectivity. When the inherent noise in the phone line is degraded or the consumer fails to install the proper filters on the phone line, the resulting noise levels can result in a degraded Internet connectivity.

How Can Signal to Noise Ratio Be Improved?

Improving the signal to noise ratio for a given system really depends on the medium of transmission and the nature of the noise or interference that is degrading the system transmission. For example, wireless networks experience a signal degradation as the distance from the router is increased which also results in a smaller SNR. The easiest way in this situation to improve the SNR is to re-locate the router to a more central location or to move the client computer closer to the router. In other systems, improving system output so that the transmitted signal has an increased gain will also result in a higher SNR and better quality of transmission. This same methodology can be applied to other systems such as digital cable runs and phone line transmission quality which can experienced significant noise from excessive cable runs and faulty cable connections. If, however, there has been an overall increase in noise introduced to a system, it can be an indicator of failed hardware or other components that require replacement before SNR will see a resulting improvement.