Browse Definitions :
Definition

noise

Also see audio noise.

Noise is unwanted electrical or electromagnetic energy that degrades the quality of signals and data.  Noise occurs in digital and analog systems, and can affect files and communications of all types, including text, programs, images, audio, and telemetry.

In a hard-wired circuit such as a telephone-line-based Internet hookup, external noise is picked up from appliances in the vicinity, from electrical transformers, from the atmosphere, and even from outer space.  Normally this noise is of little or no consequence.  However, during severe thunderstorms, or in locations were many electrical appliances are in use, external noise can affect communications.  In an Internet hookup it slows down the data transfer rate, because the system must adjust its speed to match conditions on the line.  In a voice telephone conversation, noise rarely sounds like anything other than a faint hissing or rushing.

Noise is a more significant problem in wireless systems than in hard-wired systems. In general, noise originating from outside the system is inversely proportional to the frequency, and directly proportional to the wavelength.  At a low frequency such as 300 kHz, atmospheric and electrical noise are much more severe than at a high frequency like 300 megahertz.  Noise generated inside wireless receivers, known as internal noise, is less dependent on frequency.   Engineers are more concerned about internal noise at high frequencies than at low frequencies, because the less external noise there is, the more significant the internal noise becomes.

Communications engineers are constantly striving to develop better ways to deal with noise.  The traditional method has been to minimize the signal bandwidth to the greatest possible extent.   The less spectrum space a signal occupies, the less noise is passed through the receiving circuitry.  However, reducing the bandwidth limits the maximum speed of the data that can be delivered.  Another, more recently developed scheme for minimizing the effects of noise is called digital signal processing (digital signal processing). Using fiber optics, a technology far less susceptible to noise, is another approach.

This was last updated in May 2008
SearchCompliance
  • pure risk

    Pure risk refers to risks that are beyond human control and result in a loss or no loss with no possibility of financial gain.

  • risk reporting

    Risk reporting is a method of identifying risks tied to or potentially impacting an organization's business processes.

  • chief risk officer (CRO)

    The chief risk officer (CRO) is the corporate executive tasked with assessing and mitigating significant competitive, regulatory ...

SearchSecurity
SearchHealthIT
SearchDisasterRecovery
  • What is risk mitigation?

    Risk mitigation is a strategy to prepare for and lessen the effects of threats faced by a business.

  • fault-tolerant

    Fault-tolerant technology is a capability of a computer system, electronic system or network to deliver uninterrupted service, ...

  • synchronous replication

    Synchronous replication is the process of copying data over a storage area network, local area network or wide area network so ...

SearchStorage
  • MRAM (magnetoresistive random access memory)

    MRAM (magnetoresistive random access memory) is a method of storing data bits using magnetic states instead of the electrical ...

  • storage volume

    A storage volume is an identifiable unit of data storage. It can be a removable hard disk, but it does not have to be a unit that...

  • storage capacity planning

    Storage capacity planning is the practice of assessing current data storage needs and forecasting future storage requirements.

Close