diff --git a/Makefile b/Makefile
index 3ea640b..f4bd044 100644
--- a/Makefile
+++ b/Makefile
@@ -8,7 +8,7 @@ SOURCES = main.c src/*.c
 
 # 编译选项
 CFLAGS  ?= -W -Wall -Wextra -Werror -Wundef -Wshadow -Wdouble-promotion \
-           -Wformat-truncation -fno-common -Wconversion \
+           -Wformat-truncation -fno-common \
            -g3 -Og -ffunction-sections -fdata-sections \
 		   -Iinclude -mcpu=cortex-m0plus -mthumb -lm $(EXTRA_CFLAGS)
 LDFLAGS ?= -T $(DEPS_DIR)/link.ld -nostartfiles -nostdlib --specs nano.specs  \
diff --git a/include/fft/fft.h b/include/fft/fft.h
index 4ac8ac5..dfd5005 100644
--- a/include/fft/fft.h
+++ b/include/fft/fft.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#include "inttypes.h"
+#include <inttypes.h>
 
 #define q15_t int16_t
 #define q31_t int32_t
diff --git a/include/sstv.h b/include/sstv.h
index 0be6438..36728ed 100644
--- a/include/sstv.h
+++ b/include/sstv.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#include "inttypes.h"
+#include <inttypes.h>
 
 #define float32_t float
 
diff --git a/src/fft/fft.c b/src/fft/fft.c
index 79f9fac..f359376 100644
--- a/src/fft/fft.c
+++ b/src/fft/fft.c
@@ -1,8 +1,8 @@
 #include "fft/fft.h"
 #include "fft/table.h"
-#include "inttypes.h"
-#include "math.h"
-#include "stdlib.h"
+#include <inttypes.h>
+#include <math.h>
+#include <stdlib.h>
 
 #define N 1024
 #define Re(x) 2 * x
diff --git a/src/sstv.c b/src/sstv.c
index a6b4f49..8b8c28b 100644
--- a/src/sstv.c
+++ b/src/sstv.c
@@ -3,7 +3,8 @@
 #include "fft/table.h"
 #include "math.h"
 #include "sstv.h"
-#include "stdio.h"
+#include <stdio.h>
+#include <stdlib.h>
 
 static q15_t data[N];
 static q15_t buffer[MN];
@@ -26,7 +27,8 @@ static void read_data(q15_t* pSrc, uint16_t len) {
 }
 
 static uint16_t find_peak(uint16_t L, uint16_t R) {
-    uint16_t index = 0, peak = 0;
+    q15_t peak = 0;
+    uint16_t index = 0;
     for (uint16_t i = L; i <= R; i++)
         if (data[i] > peak) {
             index = i;
@@ -38,9 +40,9 @@ static uint16_t find_peak(uint16_t L, uint16_t R) {
 static void hanning(uint16_t len) {
     for (uint16_t i = len; i < N; i++) data[i] = 0;
     if (len == 160)
-        for (uint16_t i = 0; i < len; i++) data[i] = ((q31_t)data[i] * hanning_160[i]) >> 15;
+        for (uint16_t i = 0; i < len; i++) data[i] = (q15_t)(((q31_t)data[i] * hanning_160[i]) >> 15);
     else
-        for (uint16_t i = 0; i < len; i++) data[i] = ((q31_t)data[i] * hanning_17[i]) >> 15;
+        for (uint16_t i = 0; i < len; i++) data[i] = (q15_t)(((q31_t)data[i] * hanning_17[i]) >> 15);
 }
 
 static uint32_t cSample = 0;
@@ -109,7 +111,7 @@ static uint8_t read_mode() {
         if (abs(fre - FREQ_BIT1) < 80) cBit1++;
         else if (abs(fre - FREQ_BIT0) > 80) {
             printf("Error VIS BIT: %d\r\n", fre);
-            return -1;
+            return 0;
         }
 
         if (i % 3 == 2) {
@@ -126,7 +128,7 @@ static uint8_t read_mode() {
 
     if (!cParity) {
         printf("Error Parity Check: %d\r\n", mode);
-        return -2;
+        return 0;
     }
     read_data(pData, len * 3);
     return mode;