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 in electrical engineering and circuit theory, refer to it as the **Shah function** (possibly because its graph resembles the shape of the Cyrillic letter sha ะจ). Because the Dirac comb function is periodic, it can be represented as a Fourier series:

Read more about Dirac Comb: Scaling, Fourier Series, Fourier Transform, Sampling and Aliasing, Use in Directional Statistics

### Famous quotes containing the word comb:

“So summer comes in the end to these few stains

And the rust and rot of the door through which she went.

The house is empty. But here is where she sat

To *comb* her dewy hair, a touchless light,

Perplexed by its darker iridescences.”

—Wallace Stevens (1879–1955)