DCT

Purpose:

Calculates the unitary Discrete Cosine Transform.

Syntax:

DCT(series, n)

series

-

An input series or array.

n

-

Optional. An integer, the transform length. Defaults to length(series).

Returns:

A series or array.

Example:

dct(gcos(100, 1/100, 20))

 

returns a series with a peak at 20 Hz.

Example:

dct(gcos(100, 1/100, 20), 1024)

 

Same as above, but the input is zero padded to length 1024 before the DCT is calculated.

Remarks:

The unitary discrete cosine transform is define as:

 

 

 

The DCT returns a real result for a real input series.

 

The transform is applied to each column if the input is an array.

 

Because relatively few DCT terms can be used to account for a large percentage of series energy, the DCT is often used in signal and image processing applications to perform data compression.

See Also:

DCT2

DST

IDCT

IDCT2

FFT