Quadrature Amplitude Modulation - Interference and Noise

Interference and Noise

In moving to a higher order QAM constellation (higher data rate and mode) in hostile RF/microwave QAM application environments, such as in broadcasting or telecommunications, multipath interference typically increases. There is a spreading of the spots in the constellation, decreasing the separation between adjacent states, making it difficult for the receiver to decode the signal appropriately. In other words, there is reduced noise immunity. There are several test parameter measurements which help determine an optimal QAM mode for a specific operating environment. The following three are most significant:

  • Carrier/interference ratio
  • Carrier-to-noise ratio
  • Threshold-to-noise ratio

Read more about this topic:  Quadrature Amplitude Modulation

Famous quotes containing the words interference and, interference and/or noise:

    The truth is, the whole administration under Roosevelt was demoralized by the system of dealing directly with subordinates. It was obviated in the State Department and the War Department under [Secretary of State Elihu] Root and me [Taft was the Secretary of War], because we simply ignored the interference and went on as we chose.... The subordinates gained nothing by his assumption of authority, but it was not so in the other departments.
    William Howard Taft (1857–1930)

    The truth is, the whole administration under Roosevelt was demoralized by the system of dealing directly with subordinates. It was obviated in the State Department and the War Department under [Secretary of State Elihu] Root and me [Taft was the Secretary of War], because we simply ignored the interference and went on as we chose.... The subordinates gained nothing by his assumption of authority, but it was not so in the other departments.
    William Howard Taft (1857–1930)

    Speak, ye that ride on white asses, ye that sit in judgment, and walk by the way.
    They that are delivered from the noise of archers in the places of
    drawing water, there shall they rehearse the righteous acts of the
    Lord,
    Bible: Hebrew Judges (l. V, 10–11)