V3.02

README.md

@@ -18,7 +18,7 @@ The display is a standard 16x2 LCD, but with an I2C interface. The display is co
 ## Open issues: 
 - [ ] implement proper AGC 
 - [x] implement RSSI and S-meter  
-- [ ] improve FFT-based signal processing  
+- [x] improve FFT-based signal processing  
 - [ ] revisit Si5351A driver  
 
 ## Installing and using the SDK for Windows: 

dsp.c

@@ -217,10 +217,10 @@ volatile int32_t q_sample, i_sample, a_sample;								// Latest processed sample
 /*** Include the desired DSP engine ***/
 
 #if DSP_FFT == 1
-#define AGC_TOP		 16383L
+#define AGC_TOP		 2047L
 #include "dsp_fft.c"
 #else
-#define AGC_TOP		 1500L
+#define AGC_TOP		 2047L
 #include "dsp_tim.c"
 #endif
 
@@ -345,6 +345,7 @@ bool __not_in_flash_func(dsp_callback)(repeating_timer_t *t)
 			temp = (MAX(q,((29*q/32) + (61*i/128))))>>LSH;
 		s_rssi = MAX(1,temp);
 		rx_agc = AGC_TOP/s_rssi;											// calculate required AGC factor
+		if (rx_agc==0) rx_agc=1;
 	}
 		
 #if DSP_FFT == 1

dsp_fft.c

@@ -253,7 +253,7 @@ bool __not_in_flash_func(rx)(void)
 
 
 	/*** Scale down into DAC_RANGE! ***/	
-	peak = 128;
+	peak = 256;
 	for (i=0; i<BUFSIZE; i++)									
 	{
 		A_buf[b][i] /= peak;