## Dirac delta function

The **Dirac delta** function , or δ function , is (informally) a generalized function depending on a real parameter such that it is zero for all values of the parameter except when the parameter is zero, and its integral over the parameter from −∞ to ∞ is equal to one. [ 1 ] [ 2 ] It

**wikipedia.org**| 2011/6/9 4:06:23

## Dirac measure

In mathematics , a **Dirac** measure is a measure δ x on a set X (with any σ -algebra of subsets of X ) defined by for a given and any measurable set A ⊆ X . The **Dirac** measure is a probability measure , and in terms of probability it represents the almost sure outcome x

**wikipedia.org**| 2010/9/25 11:01:39

## Dirac comb

In mathematics , a **Dirac** comb (also known as an impulse train and sampling function in electrical engineering ) is a periodic Schwartz distribution constructed from **Dirac delta** functions for some given period T . Some authors, notably Bracewell as well as some textbook authors

**wikipedia.org**| 2011/10/1 17:50:26

## Delta potential

The **delta** potential is a potential that gives rise to many interesting results in quantum mechanics. It consists of a time-independent Schrödinger equation for a particle in a potential well defined by a **Dirac delta** function in one dimension. For those familiar with the particle in

**wikipedia.org**| 2010/10/12 13:03:48

## Logarithmically-spaced Dirac comb

Like the standard **Dirac** comb , the logarithmically-spaced **Dirac** comb consists of an infinite sequence of **Dirac delta** functions . In the case of the logarithmically-spaced comb, these are spaced in octave intervals, i.e., the **delta** functions are placed at positions 2 k f 0 , for all integers

**wikipedia.org**| 2010/9/27 1:34:52

## Kronecker delta

In mathematics , the Kronecker **delta** or Kronecker's **delta** , named after Leopold Kronecker , is a function of two variables , usually integers , which is 1 if they are equal and 0 otherwise. So, for example, δ 1,2 = 0 , but δ 3,3 = 1. It is written as the symbol δ ij , and treated

**wikipedia.org**| 2011/8/6 7:47:46

## Delta-sigma modulation

A very popular application of **delta** -sigma conversion is in audio applications where a digital audio signal, as from an MP3 player, is converted into the analog audio signal which will be amplified and output by speakers or headphones. Because most of the modulator is a digital circuit, it

**wikipedia.org**| 2011/9/19 20:57:36

## List of nascent delta functions

In mathematics, a nascent **delta** function is a function δ a ( x ) that provides an approximation to the **Dirac delta** function , with the approximation becoming an identity in the limit that a approaches zero. That is, the **delta** function can be viewed as the limit of a sequence of functions

**wikipedia.org**| 2010/9/26 10:48:42

## Feynman diagram

Quantization Renormalization Vacuum state Wick's theorem Wightman axioms Equations **Dirac** equation Klein–Gordon equation Proca equations Wheeler–DeWitt equation Standard Model Electroweak interaction Higgs mechanism Quantum chromodynamics Quantum electrodynamics

**wikipedia.org**| 2011/9/27 5:58:38