1 files changed, 34 insertions, 0 deletions
diff --git a/lib/unconvert.c b/lib/unconvert.c
new file mode 100644
index 0000000..85392dd
--- /dev/null
+++ b/lib/unconvert.c
@@ -0,0 +1,34 @@
+#include "fftease.h"
+
+
+
+void unconvert( float *C, float *S, int N2, float *lastphase, float fundamental, float factor )
+
+{
+  int 		i,
+		real,
+		imag,
+		amp,
+		freq;
+  float 	mag,
+		phase;
+double sin(), cos();
+
+    for ( i = 0; i <= N2; i++ ) {
+
+	imag = freq = ( real = amp = i<<1 ) + 1;
+
+	if ( i == N2 )
+	  real = 1;
+
+	mag = C[amp];
+	lastphase[i] += C[freq] - i*fundamental;
+	phase = lastphase[i]*factor;
+	S[real] = mag*cos( phase );
+
+	if ( i != N2 )
+	  S[imag] = -mag*sin( phase );
+
+    }
+
+}