diff --git a/webrtc/common_audio/signal_processing/include/signal_processing_library.h b/webrtc/common_audio/signal_processing/include/signal_processing_library.h
index ff17009..d987e9a 100644
--- a/webrtc/common_audio/signal_processing/include/signal_processing_library.h
+++ b/webrtc/common_audio/signal_processing/include/signal_processing_library.h
@@ -456,17 +456,15 @@
 // does NOT use the 64 bit class
 //
 // Input:
-//      - auto_corr : Vector with autocorrelation values of length >=
-//                    |use_order|+1
-//      - use_order : The LPC filter order (support up to order 20)
+//      - auto_corr : Vector with autocorrelation values of length >= |order|+1
+//      - order     : The LPC filter order (support up to order 20)
 //
 // Output:
-//      - lpc_coef  : lpc_coef[0..use_order] LPC coefficients in Q12
-//      - refl_coef : refl_coef[0...use_order-1]| Reflection coefficients in
-//                    Q15
+//      - lpc_coef  : lpc_coef[0..order] LPC coefficients in Q12
+//      - refl_coef : refl_coef[0...order-1]| Reflection coefficients in Q15
 //
 // Return value     : 1 for stable 0 for unstable
-int16_t WebRtcSpl_LevinsonDurbin(int32_t* auto_corr,
+int16_t WebRtcSpl_LevinsonDurbin(const int32_t* auto_corr,
                                  int16_t* lpc_coef,
                                  int16_t* refl_coef,
                                  int16_t order);
diff --git a/webrtc/common_audio/signal_processing/levinson_durbin.c b/webrtc/common_audio/signal_processing/levinson_durbin.c
index 29f2398..e07af5d 100644
--- a/webrtc/common_audio/signal_processing/levinson_durbin.c
+++ b/webrtc/common_audio/signal_processing/levinson_durbin.c
@@ -19,7 +19,7 @@
 
 #define SPL_LEVINSON_MAXORDER 20
 
-int16_t WebRtcSpl_LevinsonDurbin(int32_t *R, int16_t *A, int16_t *K,
+int16_t WebRtcSpl_LevinsonDurbin(const int32_t* R, int16_t* A, int16_t* K,
                                  int16_t order)
 {
     int16_t i, j;
diff --git a/webrtc/common_audio/signal_processing/signal_processing_unittest.cc b/webrtc/common_audio/signal_processing/signal_processing_unittest.cc
index 611d2bf..305789e 100644
--- a/webrtc/common_audio/signal_processing/signal_processing_unittest.cc
+++ b/webrtc/common_audio/signal_processing/signal_processing_unittest.cc
@@ -371,18 +371,20 @@
 }
 
 TEST_F(SplTest, EstimatorsTest) {
-    const int kVectorSize = 4;
-    int B[] = {4, 12, 133, 1100};
-    int16_t b16[kVectorSize];
-    int32_t b32[kVectorSize];
-    int16_t bTmp16[kVectorSize];
+  const int16_t kOrder = 2;
+  const int32_t unstable_filter[] = { 4, 12, 133, 1100 };
+  const int32_t stable_filter[] = { 1100, 133, 12, 4 };
+  int16_t lpc[kOrder + 2] = { 0 };
+  int16_t refl[kOrder + 2] = { 0 };
+  int16_t lpc_result[] = { 4096, -497, 15, 0 };
+  int16_t refl_result[] = { -3962, 123, 0, 0 };
 
-    for (int kk = 0; kk < kVectorSize; ++kk) {
-        b16[kk] = B[kk];
-        b32[kk] = B[kk];
-    }
-
-    EXPECT_EQ(0, WebRtcSpl_LevinsonDurbin(b32, b16, bTmp16, 2));
+  EXPECT_EQ(0, WebRtcSpl_LevinsonDurbin(unstable_filter, lpc, refl, kOrder));
+  EXPECT_EQ(1, WebRtcSpl_LevinsonDurbin(stable_filter, lpc, refl, kOrder));
+  for (int i = 0; i < kOrder + 2; ++i) {
+    EXPECT_EQ(lpc_result[i], lpc[i]);
+    EXPECT_EQ(refl_result[i], refl[i]);
+  }
 }
 
 TEST_F(SplTest, FilterTest) {