1 files changed, 24 insertions, 9 deletions

diff --git a/Project/RTDSP/enhance.c b/Project/RTDSP/enhance.c
index e77a82c..45a0060 100644
--- a/Project/RTDSP/enhance.c
+++ b/Project/RTDSP/enhance.c
@@ -92,25 +92,27 @@ complex *fft_out;						/* FFT output */
 float *noise;
 float *power_in;
 float *mag_in;
-
+float* lpf;
 volatile int io_ptr=0;              /* Input/ouput pointer for circular buffers */
 volatile int frame_ptr=0;           /* Frame pointer */
 volatile int frame_ctr = 0;
 volatile int m_ptr = 0;
 float lambda = 0.05;
-float alpha = 20;
+float alpha = 100;
 double avg = 0;
 float *M[NUM_M];
 float mag_N_X;
 float K;
-float time_constant = 50E-6;		/* Time constant in ms */
+static float time_constant = 40e-3;		/* Time constant in ms */
 int started = 0;
  /******************************* Function prototypes *******************************/
 void init_hardware(void);    	/* Initialize codec */ 
 void init_HWI(void);            /* Initialize hardware interrupts */
 void ISR_AIC(void);             /* Interrupt service routine for codec */
 void process_frame(void);       /* Frame processing routine */
-           
+void write_spectrum(void);
+void get_noise(void);
+void low_pass_filter(void);           
 /********************************** Main routine ************************************/
 void main()
 {      
@@ -127,6 +129,7 @@ void main()
     outwin		= (float *) calloc(FFTLEN, sizeof(float));	/* Output window */
     fft_out		= (complex *) calloc(FFTLEN, sizeof(complex));	/* FFT Output */
     power_in	= (float *) calloc(FFTLEN, sizeof(float));	/* Output window */
+	lpf 		= (float *) calloc(FFTLEN, sizeof(float));	/* Output window */
     mag_in	= (float *) calloc(FFTLEN, sizeof(float));	/* Output window */
     noise	= (float *) calloc(FFTLEN, sizeof(float));	/* Output window */
 	
@@ -149,11 +152,8 @@ void main()
   	for (k = 0; k < NUM_M; ++k) {
   		M[k] = (float *) calloc(FFTLEN, sizeof(float));
   	}
-  	
-  	// initializing the value to estimate the low pass filter
-  	K = exp(- TFRAME / time_constant);
 
- 							
+ 	K = exp(-TFRAME/time_constant);			
   	/* main loop, wait for interrupt */  
   	while(1) 	process_frame();
 }
@@ -204,6 +204,7 @@ void write_spectrum(void) {
 	}
 }
 
+// Noise estimataion
 void get_noise(void) {
 	int k, i, min_i;
 	float min_val;
@@ -220,6 +221,18 @@ void get_noise(void) {
 		noise[k] = alpha * M[min_i][k];
 	}
 }
+
+
+// Low pass filter X(w)
+void low_pass_filter(void) {
+	int w;
+	float temp;
+	for (w = 0; w < FFTLEN; ++w) {
+		temp = power_in[w];
+		power_in[w] = (1-K)*power_in[w] + K*lpf[w];
+		lpf[w] = temp;
+	}
+}
         
 /******************************** process_frame() ***********************************/  
 void process_frame(void)
@@ -249,7 +262,7 @@ void process_frame(void)
 	} 
 	
 	/************************* DO PROCESSING OF FRAME  HERE **************************/
-
+	
 	// Initialise the array fft_out for FFT
 	for (k = 0; k < FFTLEN; ++k) {
 		fft_out[k] = cmplx(inframe[k], 0.0);
@@ -262,6 +275,8 @@ void process_frame(void)
 	for (k = 0; k < FFTLEN; ++k) {
 		power_in[k] = sqrt(fft_out[k].r * fft_out[k].r + fft_out[k].i * fft_out[k].i);
 	}
+	
+	//low_pass_filter();
 
 	// Get average of fft_out and write to Spectrum
 	write_spectrum();