+void iceFsk3(int * data, const size_t len){
+
+       int i,j;
+       
+       int * output =  (int* ) malloc(sizeof(int) * len);      
+       memset(output, 0x00, len);
+       float fc           = 0.1125f;          // center frequency
+       size_t adjustedLen = len;
+       
+    // create very simple low-pass filter to remove images (2nd-order Butterworth)
+    float complex iir_buf[3] = {0,0,0};
+    float b[3] = {0.003621681514929,  0.007243363029857, 0.003621681514929};
+    float a[3] = {1.000000000000000, -1.822694925196308, 0.837181651256023};
+    
+    float sample           = 0;      // input sample read from file
+    float complex x_prime  = 1.0f;   // save sample for estimating frequency
+    float complex x;
+               
+       for (i=0; i<adjustedLen; ++i) {
+
+               sample = data[i]+128;
+               
+        // remove DC offset and mix to complex baseband
+        x = (sample - 127.5f) * cexpf( _Complex_I * 2 * M_PI * fc * i );
+
+        // apply low-pass filter, removing spectral image (IIR using direct-form II)
+        iir_buf[2] = iir_buf[1];
+        iir_buf[1] = iir_buf[0];
+        iir_buf[0] = x - a[1]*iir_buf[1] - a[2]*iir_buf[2];
+        x          = b[0]*iir_buf[0] +
+                     b[1]*iir_buf[1] +
+                     b[2]*iir_buf[2];
+                                        
+        // compute instantaneous frequency by looking at phase difference
+        // between adjacent samples
+        float freq = cargf(x*conjf(x_prime));
+        x_prime = x;    // retain this sample for next iteration
+
+               output[i] =(freq > 0)? 10 : -10;
+    } 
+
+       // show data
+       for (j=0; j<adjustedLen; ++j)
+               data[j] = output[j];
+               
+       CmdLtrim("30");
+       adjustedLen -= 30;