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Function: time_freq_map()

void time_freq_map(float *htilde, struct_tfparam *tfs,int index,float **tfgeneral,float **pic)

This function is the main routine responsible for creating the time-frequency map. Currently three algorithms are implemented for creating TF maps from time series data, namely, the Wigner-Ville distribution, the Windowed Fourier transform and the Choi-Williams distribution. There are two versions of the Wigner-Ville transform which have both been implemented. This function calls the appropriate transform routine based on the variabel (*tfs).transformtype.

The arguments are:

float *htilde: Input. The pointer to the beginning of the data segment.
struct_tfparam *tfs: Input. A pointer to a structure (defined in the previous subsection).
int index: Input. The subsegment for which the map is to be computed.
float **tfgeneral: Input. A temporary work space. Memory must be allocated by the calling program. tfgeneral must point to an array of size ((*tfs).TD * sizeof(*float)). Each of these pointers must be allocated a space of ((*tfs).ND * sizeof(float)) bytes.
float **pic: Output. The computed TF map. Memory must be allocated by the calling program. pic must point to an array of size ((*tfs).PD * sizeof(*float)). Each of these pointers must be allocated a space of ((*tfs).PD * sizeof(float)) bytes.

In addition to the arguments the structure variable (*tfs) contains all the additional parameters for the construction of the map. This structure is defined in the previous subsection.

Author: R. Balasubramanian, bala@chandra.phys.uwm.edu


next up previous contents
Next: Function compute_scalefactor() Up: GRASP Routines: Time-Frequency Methods Previous: Structure: struct struct_tfparam   Contents
Bruce Allen 2000-11-19