Granular Distortion and Overload Distortion
Often the design of a quantizer involves supporting only a limited range of possible output values and performing clipping to limit the output to this range whenever the input exceeds the supported range. The error introduced by this clipping is referred to as overload distortion. Within the extreme limits of the supported range, the amount of spacing between the selectable output values of a quantizer is referred to as its granularity, and the error introduced by this spacing is referred to as granular distortion. It is common for the design of a quantizer to involve determining the proper balance between granular distortion and overload distortion. For a given supported number of possible output values, reducing the average granular distortion may involve increasing the average overload distortion, and vice-versa. A technique for controlling the amplitude of the signal (or, equivalently, the quantization step size ) to achieve the appropriate balance is the use of automatic gain control (AGC). However, in some quantizer designs, the concepts of granular error and overload error may not apply (e.g., for a quantizer with a limited range of input data or with a countably infinite set of selectable output values).
Read more about this topic: Quantizer
Famous quotes containing the words granular, distortion and/or overload:
“I feel like a white granular mass of amorphous crystals—my formula appears to be isomeric with Spasmotoxin. My aurochloride precipitates into beautiful prismatic needles. My Platinochloride develops octohedron crystals,—with a fine blue florescence. My physiological action is not indifferent. One millionth of a grain injected under the skin of a frog produced instantaneous death accompanied by an orange blossom odor.”
—Lafcadio Hearn (1850–1904)
“A man’s memory is bound to be a distortion of his past in accordance with his present interests, and the most faithful autobiography is likely to mirror less what a man was than what he has become.”
—Fawn M. Brodie (1915–1981)
“I am a dreamer of words, of written words. I think I am reading; a word stops me. I leave the page. The syllables of the word begin to move around. Stressed accents begin to invert. The word abandons its meaning like an overload which is too heavy and prevents dreaming. Then words take on other meanings as if they had the right to be young. And the words wander away, looking in the nooks and crannies of vocabulary for new company, bad company.”
—Gaston Bachelard (1884–1962)