fix: #52

main.c

@@ -755,9 +755,10 @@ void
 set_frequencies(uint32_t start, uint32_t stop, int16_t points)
 {
   int i;
-  uint32_t span = (stop - start) / 1000; /* prevents overflow because of maximum of int32_t(2.147e+9) */  
+  float span = stop - start;
   for (i = 0; i < points; i++)
-    frequencies[i] = start + span * i / (points - 1) * 1000;
+    frequencies[i] = start + i * span / (float)(points - 1);
+  // disable at out of sweep range
   for (; i < sweep_points; i++)
     frequencies[i] = 0;
 }