/* SigLib One-pole Filter Example */ #include #include #include #include "GraphFunctions.h" /* Define constants */ #define SAMPLE_LENGTH ((SLArrayIndex_t)512) #define FFT_SIZE ((SLArrayIndex_t)512) #define HALF_FFT_SIZE ((SLArrayIndex_t)256) #define LOG_FFT_SIZE ((SLArrayIndex_t)9) SLData_t *pRealData, *pImagData, *pResults, *pSrc1, *pSrc2, *filtered, *delay, *pFFTCoeffs; SLData_t Alpha, Offset, OnePoleFilterState, SinePhase; void main(int argc,char **argv) { GraphObject *h2DGraph; /* Declare graph object */ if (argc != 2) { printf ("\nsyntax: Test_op \n\n"); exit (0); } Alpha = (SLData_t) atof (argv[1]); /* Allocate memory */ pSrc1 = SUF_VectorArrayAllocate (SAMPLE_LENGTH); pSrc2 = SUF_VectorArrayAllocate (SAMPLE_LENGTH); pRealData = SUF_VectorArrayAllocate (FFT_SIZE); pImagData = SUF_VectorArrayAllocate (FFT_SIZE); pResults = SUF_VectorArrayAllocate (FFT_SIZE); /* RMS result array */ filtered = SUF_VectorArrayAllocate (HALF_FFT_SIZE); delay = SUF_VectorArrayAllocate (HALF_FFT_SIZE); pFFTCoeffs = SUF_FftCoefficientAllocate (FFT_SIZE); h2DGraph = /* Initialize graph */ Create2DGraph ("One-pole Filter", /* Graph title */ "Time / Frequency", /* 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); } /* Initialise FFT */ SIF_Fft (pFFTCoeffs, /* Pointer to FFT coefficients */ SIGLIB_NULL_ARRAY_INDEX_PTR, /* Pointer to bit reverse address table - NOT USED */ FFT_SIZE); /* FFT Size */ SDA_SignalGenerate (pSrc1, /* Pointer to destination array */ SIGLIB_STEP, /* Signal type - step function */ SIGLIB_ONE, /* Signal peak level */ SIGLIB_FILL, /* Fill (overwrite) or add to existing array contents */ SIGLIB_ZERO, /* Signal frequency - Unused */ SIGLIB_ZERO, /* D.C. Offset */ SIGLIB_TEN, /* Unused */ SIGLIB_ZERO, /* Signal end value - Unused */ SIGLIB_NULL_DATA_PTR, /* Unused */ SIGLIB_NULL_DATA_PTR, /* Unused */ SAMPLE_LENGTH); /* Output array length */ SIF_OnePole (&OnePoleFilterState); SDA_OnePole (pSrc1, pSrc2, Alpha, &OnePoleFilterState, SAMPLE_LENGTH); Display2DGraph (h2DGraph, /* Graph handle */ "Unfiltered Signal", /* Title of the dataset */ pSrc1, /* Array of Double dataset */ SAMPLE_LENGTH, /* Number of data points */ SV_GRAPH_LINE, /* Graph type */ SV_BLUE, /* Colour */ SV_HIDE_MARKERS, /* Marker enable / disable */ SV_GRAPH_NEW); /* New graph */ Display2DGraph (h2DGraph, /* Graph handle */ "One-pole Filtered Signal", /* Title of the dataset */ pSrc2, /* Array of Double dataset */ SAMPLE_LENGTH, /* Number of data points */ SV_GRAPH_LINE, /* Graph type */ SV_RED, /* Colour */ SV_HIDE_MARKERS, /* Marker enable / disable */ SV_GRAPH_ADD); /* New graph */ printf ("\nUnfiltered And One-pole Filtered Signal\nPlease hit to continue . . ."); getchar (); /* Copy data for FFT */ SDA_Copy (pSrc2, /* Pointer to source array */ pRealData, /* Pointer to destination array */ FFT_SIZE); /* Array length */ /* Perform real FFT */ SDA_Rfft (pRealData, /* Pointer to real array */ pImagData, /* Pointer to imaginary array */ pFFTCoeffs, /* Pointer to FFT coefficients */ SIGLIB_NULL_ARRAY_INDEX_PTR, /* Pointer to bit reverse address table - NOT USED */ FFT_SIZE, /* FFT size */ LOG_FFT_SIZE); /* log2 FFT size */ /* Calculate real power from complex */ SDA_LogMagnitude (pRealData, /* Pointer to real source array */ pImagData, /* Pointer to imaginary source array */ pResults, /* Pointer to log magnitude destination array */ FFT_SIZE); /* Array length */ Display2DGraph (h2DGraph, /* Graph handle */ "Frequency Response Of One-pole Filter", /* Title of the dataset */ pResults, /* Array of Double dataset */ SAMPLE_LENGTH, /* Number of data points */ SV_GRAPH_LINE, /* Graph type */ SV_BLUE, /* Colour */ SV_HIDE_MARKERS, /* Marker enable / disable */ SV_GRAPH_NEW); /* New graph */ printf ("\nFrequency Response Of One-pole Filter\nPlease hit to continue . . ."); getchar (); SinePhase = SIGLIB_ZERO; printf ("512 Point FFT, quantized data - one pole filter per bin (Alpha = %lf)\n", Alpha); OnePoleFilterState = SIGLIB_FIRST_SAMPLE; /* Initialise one pole filter state array */ SDA_Clear (delay, /* Pointer to destination array */ HALF_FFT_SIZE); /* Array length */ while (!kbhit()) { SDA_SignalGenerate (pRealData, /* 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)0.0625), /* 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 */ FFT_SIZE); /* Output array length */ /* Quantisation - leads to spurious noise */ SDA_Quantize (pRealData, /* Pointer to source array */ pRealData, /* Pointer to destination array */ 8, /* Quantisation */ SIGLIB_ONE, /* Peak value */ FFT_SIZE); /* Source array size */ /* Uncorrelated noise (8 bit ) */ SDA_SignalGenerate (pRealData, /* Pointer to destination array */ SIGLIB_WHITE_NOISE, /* Signal type - random white noise */ ((SLData_t)0.003906), /* Signal peak level */ SIGLIB_ADD, /* Fill (overwrite) or add to existing array contents */ SIGLIB_ZERO, /* Signal frequency - Unused */ SIGLIB_ZERO, /* D.C. Offset */ SIGLIB_ZERO, /* Unused */ SIGLIB_ZERO, /* Signal end value - Unused */ SIGLIB_NULL_DATA_PTR, /* Unused */ SIGLIB_NULL_DATA_PTR, /* Unused */ FFT_SIZE); /* Output array length */ /* Perform real FFT */ SDA_Rfft (pRealData, /* Pointer to real array */ pImagData, /* Pointer to imaginary array */ pFFTCoeffs, /* Pointer to FFT coefficients */ SIGLIB_NULL_ARRAY_INDEX_PTR, /* Pointer to bit reverse address table - NOT USED */ FFT_SIZE, /* FFT size */ LOG_FFT_SIZE); /* log2 FFT size */ /* Calculate real power from complex */ SDA_LogMagnitude (pRealData, /* Pointer to real source array */ pImagData, /* Pointer to imaginary source array */ pResults, /* Pointer to log magnitude destination array */ FFT_SIZE); /* Array length */ Offset = SDA_AbsMax (pResults, /* Pointer to source array */ FFT_SIZE); /* Array length */ SDA_Offset (pResults, /* Pointer to source array */ Offset, /* D.C. offset */ pResults, /* Pointer to destination array */ FFT_SIZE); /* Array length */ SDA_OnePolePerSample (pResults, /* Pointer to input data */ filtered, /* Pointer to destination array */ delay, /* Pointer to state array */ Alpha, /* Filter alpha */ HALF_FFT_SIZE); /* Array length */ Display2DGraph (h2DGraph, /* Graph handle */ "Filtered Signal", /* Title of the dataset */ filtered, /* Array of Double dataset */ HALF_FFT_SIZE, /* Number of data points */ SV_GRAPH_STEM, /* Graph type */ SV_BLUE, /* Colour */ SV_SHOW_MARKERS, /* Marker enable / disable */ SV_GRAPH_NEW); /* New graph */ } if (kbhit()) getchar (); /* Clear keyboard buffer */ SUF_MemoryFree (pSrc1); /* Free memory */ SUF_MemoryFree (pSrc2); SUF_MemoryFree (pRealData); SUF_MemoryFree (pImagData); SUF_MemoryFree (pResults); SUF_MemoryFree (filtered); SUF_MemoryFree (delay); SUF_MemoryFree (pFFTCoeffs); }