John W. Campbell

Class, constructor and methods:

Class DetailsAccessible Fields

Constructor

Calculate Complex and Real FFT's

- Package:
- Jdl.JdlLib;
- Class name:
- JdlFFT
- Class definition:
- public class JdlFFT
- Extends:
- Object
- Implements:
- none
- Actions:
- none

Constructor:

Standard constructor*Constructor Definition:*- public JdlFFT ()
*Parameters List:*- none

Methods:

Complex Fourier transform - complexTransformReal Fourier transform - realTransform

*Method Definition:*- public int complexTransform(float[] x, int npow, int isgn)
*Parameters List:*- x
- Array of data to be transformed (2*npow**2 points). The real and imaginary components of the data are stored in adjacant elements in the float array. The output is written back to this array.
- npow
- The power of two. There are 2**npow points in the transform.
- isgn
- Flag =1, forward transform, =-1 reverse transform.

*Method Return:*-
Error flag:

=0, OK

=1, Error in parameters

*Method Definition:*- public int realTransform(float[] x, int npow, int isgn)
*Parameters List:*- x
- Array of real data to be transformed (2*npow**2 elements in length). On input values are stored in the first 2**npow elements. On output the complex data are stored in 2**npow pairs of data values with the real and imaginary components in adjacant locations in the real array.
- npow
- The power of two. There are 2**npow points in the transform. npow must be > 1.
- isgn
- Sign flag:

= 1, Forward transform -> half of complex transform 2**NPOW/2 real/imag pairs.

= 2, Forward transform -> full complex transform 2**NPOW real/imag pairs.

= -1, Reverse transform (from half complex transform).

= -2, Reverse transform (from full complex transform).

*Method Return:*-
Error flag:

= 0, OK.

= 1, Error in parameters.

⇑ Up 2 ⇑ Up 1 ⇑ Top of this