hilbert.c

希尔伯特变换Hilbert算法

/* SigLib Hilbert Transform Example */

#include <stdio.h>
#include <siglib.h>
#include "GraphFunctions.h"

/* Define constants */
#define	SAMPLE_LENGTH				((SLArrayIndex_t)512)
#define	HILBERT_TRANSFORM_LENGTH	41L
#define DELAY_LENGTH				(HILBERT_TRANSFORM_LENGTH >> 1)

SLData_t		*pSrc;
SLData_t		*pFilterCoeffs, *pFilterState;
SLData_t		*pDelayState;
SLData_t		*pHilbertTransformed, *pDelayed;
SLArrayIndex_t	FilterIndex, DelayIndex;
SLData_t		SinePhase;

void	main(void);

void main(void)
{
	GraphObject *h2DGraph;							/* Declare graph object */

	SLArrayIndex_t	i;

	h2DGraph =										/* Initialize graph */
		Create2DGraph ("Hilbert Transform",			/* Graph title */
					   "Time",						/* X-Axis label */
					   "Magnitude",					/* Y-Axis label */
					   SV_AUTO_SCALE,				/* Scaling mode */
					   SV_SIGNED,					/* Sign mode */
					   SV_GRAPH_LINE,				/* Graph type */
					   "localhost");				/* Graph server */
	if (h2DGraph == NULL)							/* Graph creation failed - e.g is server running ? */
	{
		printf ("\nGraph creation failure. Please check that the server is running\n");
		exit (1);
	}

	pSrc = SUF_VectorArrayAllocate (SAMPLE_LENGTH);
	pFilterCoeffs = SUF_VectorArrayAllocate (HILBERT_TRANSFORM_LENGTH);
	pFilterState = SUF_VectorArrayAllocate (HILBERT_TRANSFORM_LENGTH);
	pHilbertTransformed = SUF_VectorArrayAllocate (SAMPLE_LENGTH);
	pDelayState = SUF_VectorArrayAllocate (DELAY_LENGTH);
	pDelayed = SUF_VectorArrayAllocate (SAMPLE_LENGTH);

													/* Initialise Hilbert transformer coefficients */
	SIF_HilbertTransformer (pFilterCoeffs,			/* Pointer to filter coefficients */
							HILBERT_TRANSFORM_LENGTH);	/* Filter length */	
													/* Initialise FIR filter for Hilbert transformer */
	SIF_Fir (pFilterState,							/* Pointer to filter state array */
			 &FilterIndex,							/* Pointer to filter index register */
			 HILBERT_TRANSFORM_LENGTH);				/* Filter length */
													/* Initialise the delay */
	SIF_Delay (pDelayState,							/* Pointer to delay state array */
			   &DelayIndex,							/* Pointer to delay index */
			   DELAY_LENGTH);						/* Delay length */

	SinePhase = SIGLIB_ZERO;
	SDA_SignalGenerate (pSrc,						/* Pointer to destination array */
						SIGLIB_SINE_WAVE,			/* Signal type - Sine wave */
						SIGLIB_ONE,					/* Signal peak level */
						SIGLIB_FILL,				/* Fill (overwrite) or add to existing array contents */
						((SLData_t)0.01),			/* Signal frequency */
						SIGLIB_ZERO,				/* D.C. Offset */
						SIGLIB_ZERO,				/* Unused */
						SIGLIB_ZERO,				/* Signal end value - Unused */
						&SinePhase,					/* Signal phase - maintained across array boundaries */
						SIGLIB_NULL_DATA_PTR,		/* Unused */
						SAMPLE_LENGTH);				/* Output array length */

	Display2DGraph (h2DGraph,						/* Graph handle */
				    "Source Signal",				/* Title of the dataset */
				    pSrc,							/* Array of Double dataset */
				    SAMPLE_LENGTH,					/* Number of data points */
					SV_GRAPH_LINE,					/* Graph type */
				    SV_MAGENTA,						/* Colour */
					SV_HIDE_MARKERS,				/* Marker enable / disable */
					SV_GRAPH_NEW);					/* New graph */
	printf ("\nSource Signal\nPlease hit <Carriage Return> to continue . . ."); getchar ();

													/* Apply Hilbert transformerer */
	SDA_Fir (pSrc,									/* Input array to be filtered */
			 pHilbertTransformed,					/* Filtered output array */
			 pFilterState,							/* Pointer to filter state array */
			 pFilterCoeffs,							/* Pointer to filter coefficients */
			 &FilterIndex,							/* Pointer to filter index register */
			 HILBERT_TRANSFORM_LENGTH,				/* Filter length */
			 SAMPLE_LENGTH);						/* Array length */

	Display2DGraph (h2DGraph,						/* Graph handle */
				    "Hilbert Transformed Signal",	/* Title of the dataset */
				    pHilbertTransformed,			/* Array of Double dataset */
				    SAMPLE_LENGTH,					/* Number of data points */
					SV_GRAPH_LINE,					/* Graph type */
				    SV_MAGENTA,						/* Colour */
					SV_HIDE_MARKERS,				/* Marker enable / disable */
					SV_GRAPH_NEW);					/* New graph */
	printf ("\nHilbert Transformed Signal\nPlease hit <Carriage Return> to continue . . ."); getchar ();

						/* Delay input signal */
//	SDA_Delay (pSrc, pDelayed, pDelayState, &DelayIndex, DELAY_LENGTH, SAMPLE_LENGTH);

	for (i = 0; i < SAMPLE_LENGTH; i++)
	{
		*(pDelayed+i) =
			SDS_Delay (*(pSrc+i),					/* Input data sample */
					   pDelayState,					/* Pointer to delay state array */
					   &DelayIndex,					/* Pointer to delay state index */
					   DELAY_LENGTH);				/* Delay filter length */
	}

	Display2DGraph (h2DGraph,						/* Graph handle */
				    "Delayed Signal",				/* Title of the dataset */
				    pDelayed,						/* Array of Double dataset */
				    SAMPLE_LENGTH,					/* Number of data points */
					SV_GRAPH_LINE,					/* Graph type */
				    SV_MAGENTA,						/* Colour */
					SV_HIDE_MARKERS,				/* Marker enable / disable */
					SV_GRAPH_NEW);					/* New graph */
	printf ("\nDelayed Signal\nPlease hit <Carriage Return> to continue . . ."); getchar ();

	SUF_MemoryFree (pSrc);							/* Free memory */
	SUF_MemoryFree (pFilterCoeffs);
	SUF_MemoryFree (pFilterState);
	SUF_MemoryFree (pHilbertTransformed);
	SUF_MemoryFree (pDelayState);
	SUF_MemoryFree (pDelayed);
}