diff --git a/app/src/main/rs/calibration_detector.rsh b/app/src/main/rs/calibration_detector.rsh
index adb691c..2293b96 100644
--- a/app/src/main/rs/calibration_detector.rsh
+++ b/app/src/main/rs/calibration_detector.rsh
@@ -19,18 +19,14 @@ limitations under the License.
 
 #include "constants.rsh"
 #include "state.rsh"
+#include "pulse.rsh"
 
 static int calibration_detected(int cnt_quantized)
 {
-    static int ssb_counter;
-    int ssb_level = cnt_quantized == 0;
-    int ssb_pulse = !ssb_level && ssb_counter >= ssb_length;
-    ssb_counter = ssb_level ? ssb_counter + 1 : 0;
-
-    static int bit_pos, vis_pos, vis_code;
+    static int bit_pos = 8, vis_pos, vis_code;
     static int vis_counter, bit_counter;
 
-    if (ssb_pulse) {
+    if (pulse_detected(&start_bit_detector, cnt_quantized == 0)) {
         vis_code = 0;
         bit_pos = 0;
         vis_pos = 2 * bit_length;
diff --git a/app/src/main/rs/decoder.rs b/app/src/main/rs/decoder.rs
index 4694c19..0cb696f 100644
--- a/app/src/main/rs/decoder.rs
+++ b/app/src/main/rs/decoder.rs
@@ -21,6 +21,7 @@ limitations under the License.
 #include "ema.rsh"
 #include "ddc.rsh"
 #include "fmd.rsh"
+#include "pulse.rsh"
 #include "scanline_estimator.rsh"
 #include "calibration_detector.rsh"
 #include "initialization.rsh"
@@ -39,7 +40,7 @@ void reset_buffer()
     prev_sync_pos = sync_pos = 0;
     buffer_pos = 0;
     seperator_counter = 0;
-    sync_counter = sync_length;
+    fake_pulse(&sync_pulse_detector);
     buffer_cleared = 1;
     for (int i = 0; i < maximum_width * maximum_height; ++i)
         pixel_buffer[i] = rgb(0, 0, 0);
@@ -275,11 +276,10 @@ void decode(int samples) {
         int dat_quantized = round(dat_value);
 
         int sync_level = cnt_active && cnt_quantized == 0;
-        int sync_pulse = !sync_level && sync_counter >= sync_length;
-        sync_counter = sync_level ? sync_counter + 1 : 0;
+        int sync_pulse = pulse_detected(&sync_pulse_detector, sync_level);
         if (sync_pulse) {
             prev_sync_pos = sync_pos;
-            sync_pos = buffer_pos - sync_buildup_length;
+            sync_pos = buffer_pos + trailing_edge_position(&sync_pulse_detector);
         }
 
         static int reset_on_first_sync;
diff --git a/app/src/main/rs/initialization.rsh b/app/src/main/rs/initialization.rsh
index 60b0868..2bc6c12 100644
--- a/app/src/main/rs/initialization.rsh
+++ b/app/src/main/rs/initialization.rsh
@@ -41,16 +41,15 @@ void initialize(float rate, int length, int iw, int ih, int sw, int sh, int sgw,
     hpos = 0;
     prev_sync_pos = sync_pos = 0;
     buffer_pos = 0;
-    sync_counter = 0;
     seperator_counter = 0;
     buffer_cleared = 0;
     free_running = 1;
-    minimum_sync_length = 0.002f * sample_rate;
-    const float sync_len_tolerance = 0.7;
-    min_sync_length_5ms = sync_len_tolerance * 0.005f * sample_rate;
-    min_sync_length_9ms = sync_len_tolerance * 0.009f * sample_rate;
-    min_sync_length_20ms = sync_len_tolerance * 0.020f * sample_rate;
-    sync_buildup_length = round((sync_buildup_ms * sample_rate) / 1000.0f);
+
+    const float sync_tolerance = 0.7;
+    sync_pulse_detector_5ms = init_pulse(sync_tolerance * 5.0f, sync_buildup_ms, sample_rate);
+    sync_pulse_detector_9ms = init_pulse(sync_tolerance * 9.0f, sync_buildup_ms, sample_rate);
+    sync_pulse_detector_20ms = init_pulse(sync_tolerance * 20.0f, sync_buildup_ms, sample_rate);
+    sync_pulse_detector = init_pulse(2.0f, sync_buildup_ms, sample_rate);
 
     robot36_scanline_length = round((robot36_scanline_ms * sample_rate) / 1000.0f);
     robot72_scanline_length = round((robot72_scanline_ms * sample_rate) / 1000.0f);
@@ -72,12 +71,12 @@ void initialize(float rate, int length, int iw, int ih, int sw, int sh, int sgw,
     maximum_absolute_deviaton = 0.5f * pairwise_minimum_of_scanline_time_distances * sample_rate;
     maximum_variance = pown(0.0005f * sample_rate, 2);
 
-    const float vis_seconds = 0.3f;
-    const float bit_seconds = 0.03f;
-    const float ssb_tolerance = 0.9f;
-    vis_length = vis_seconds * sample_rate;
-    bit_length = bit_seconds * sample_rate;
-    ssb_length = ssb_tolerance * bit_seconds * sample_rate;
+    const float vis_ms = 300.0f;
+    const float bit_ms = 30.0f;
+    vis_length = round((vis_ms * sample_rate) / 1000.0f);
+    bit_length = round((bit_ms * sample_rate) / 1000.0f);
+    const float start_bit_tolerance = 0.9f;
+    start_bit_detector = init_pulse(start_bit_tolerance * bit_ms, 0, sample_rate);
 
     const float dat_carrier = 1900.0f;
     const float cnt_carrier = 1200.0f;
diff --git a/app/src/main/rs/modes.rsh b/app/src/main/rs/modes.rsh
index 8589e52..c9e2e3f 100644
--- a/app/src/main/rs/modes.rsh
+++ b/app/src/main/rs/modes.rsh
@@ -33,7 +33,7 @@ void raw_mode()
     freerun_height = maximum_height;
     bitmap_width = maximum_width;
     bitmap_height = maximum_height;
-    sync_length = minimum_sync_length;
+    sync_pulse_detector = init_pulse(2.0f, sync_buildup_ms, sample_rate);
     minimum_length = 0.05f * sample_rate;
     maximum_length = buffer_length;
     scanline_length = maximum_length;
@@ -55,7 +55,7 @@ void robot36_mode()
     const float uv_scan_ms = 44.0f;
     const float seperator_ms = 4.5f;
     seperator_length = round((seperator_ms * sample_rate) / 1000.0f);
-    sync_length = tolerance * (sync_ms * sample_rate) / 1000.0f;
+    sync_pulse_detector = init_pulse(tolerance * sync_ms, sync_buildup_ms, sample_rate);
 
     float y_begin_ms = sync_porch_ms;
     float y_end_ms = y_begin_ms + y_scan_ms;
@@ -92,7 +92,7 @@ void robot72_mode()
     const float uv_scan_ms = 69.0f;
     const float seperator_ms = 4.5f;
     seperator_length = round((seperator_ms * sample_rate) / 1000.0f);
-    sync_length = tolerance * (sync_ms * sample_rate) / 1000.0f;
+    sync_pulse_detector = init_pulse(tolerance * sync_ms, sync_buildup_ms, sample_rate);
 
     float y_begin_ms = sync_porch_ms;
     float y_end_ms = y_begin_ms + y_scan_ms;
@@ -132,7 +132,7 @@ static void pd_mode(int mode, int scanline, int blur, float yuv_scan_ms, int wid
     const float tolerance = 0.8f;
     const float sync_ms = 20.0f;
     const float porch_ms = 2.08f;
-    sync_length = tolerance * (sync_ms * sample_rate) / 1000.0f;
+    sync_pulse_detector = init_pulse(tolerance * sync_ms, sync_buildup_ms, sample_rate);
 
     float y_even_begin_ms = porch_ms;
     float y_even_end_ms = y_even_begin_ms + yuv_scan_ms;
@@ -177,7 +177,7 @@ static void martin_mode(int mode, int scanline, int blur, float rgb_scan_ms)
     const float sync_porch_ms = 0.572f;
     const float seperator_ms = 0.572f;
     seperator_length = round((seperator_ms * sample_rate) / 1000.0f);
-    sync_length = tolerance * (sync_ms * sample_rate) / 1000.0f;
+    sync_pulse_detector = init_pulse(tolerance * sync_ms, sync_buildup_ms, sample_rate);
 
     float g_begin_ms = sync_porch_ms;
     float g_end_ms = g_begin_ms + rgb_scan_ms;
@@ -213,7 +213,7 @@ static void scottie_mode(int mode, int scanline, int blur, float rgb_scan_ms)
     const float sync_porch_ms = 1.5f;
     const float seperator_ms = 1.5f;
     seperator_length = round((seperator_ms * sample_rate) / 1000.0f);
-    sync_length = tolerance * (sync_ms * sample_rate) / 1000.0f;
+    sync_pulse_detector = init_pulse(tolerance * sync_ms, sync_buildup_ms, sample_rate);
 
     float r_begin_ms = sync_porch_ms;
     float r_end_ms = r_begin_ms + rgb_scan_ms;
@@ -249,7 +249,7 @@ void wraaseSC2_180_mode()
     const float sync_ms = 5.5225f;
     const float sync_porch_ms = 0.5f;
     const float rgb_scan_ms = 235.0f;
-    sync_length = tolerance * (sync_ms * sample_rate) / 1000.0f;
+    sync_pulse_detector = init_pulse(tolerance * sync_ms, sync_buildup_ms, sample_rate);
 
     float r_begin_ms = sync_porch_ms;
     float r_end_ms = r_begin_ms + rgb_scan_ms;
diff --git a/app/src/main/rs/pulse.rsh b/app/src/main/rs/pulse.rsh
new file mode 100644
index 0000000..4a6ba4d
--- /dev/null
+++ b/app/src/main/rs/pulse.rsh
@@ -0,0 +1,46 @@
+/*
+Copyright 2015 Ahmet Inan <xdsopl@googlemail.com>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+ */
+
+#ifndef PULSE_RSH
+#define PULSE_RSH
+
+typedef struct {
+    int counter, length, buildup;
+} pulse_t;
+
+static pulse_t init_pulse(float length, float buildup, int rate)
+{
+    return (pulse_t){ 0, round((length * rate) / 1000.0f), round((buildup * rate) / 1000.0f) };
+}
+
+static int pulse_detected(pulse_t *pulse, int level)
+{
+    int trailing_edge = !level && pulse->counter >= pulse->length;
+    pulse->counter = level ? pulse->counter + 1 : 0;
+    return trailing_edge;
+}
+
+static void fake_pulse(pulse_t *pulse)
+{
+    pulse->counter = pulse->length;
+}
+
+static int trailing_edge_position(pulse_t *pulse)
+{
+    return -pulse->buildup;
+}
+
+#endif
\ No newline at end of file
diff --git a/app/src/main/rs/scanline_estimator.rsh b/app/src/main/rs/scanline_estimator.rsh
index 3fdc92d..8ee6604 100644
--- a/app/src/main/rs/scanline_estimator.rsh
+++ b/app/src/main/rs/scanline_estimator.rsh
@@ -20,27 +20,24 @@ limitations under the License.
 #include "constants.rsh"
 #include "state.rsh"
 #include "sma.rsh"
+#include "pulse.rsh"
 
 static int scanline_estimator(int sync_level)
 {
-    static int sync_counter;
-    int sync_pulse = !sync_level && sync_counter >= minimum_sync_length;
-    int sync_len = sync_counter;
-    sync_counter = sync_level ? sync_counter + 1 : 0;
-
     static int scanline_counter_5ms, scanline_counter_9ms, scanline_counter_20ms;
     ++scanline_counter_5ms;
     ++scanline_counter_9ms;
     ++scanline_counter_20ms;
 
-    if (!sync_pulse)
-        return -1;
-
     scanline_counter_5ms = scanline_counter_5ms >= buffer_length ? 0 : scanline_counter_5ms;
     scanline_counter_9ms = scanline_counter_9ms >= buffer_length ? 0 : scanline_counter_9ms;
     scanline_counter_20ms = scanline_counter_20ms >= buffer_length ? 0 : scanline_counter_20ms;
 
-    if (sync_len >= min_sync_length_20ms) {
+    int sync_pulse_5ms = pulse_detected(&sync_pulse_detector_5ms, sync_level);
+    int sync_pulse_9ms = pulse_detected(&sync_pulse_detector_9ms, sync_level);
+    int sync_pulse_20ms = pulse_detected(&sync_pulse_detector_20ms, sync_level);
+
+    if (sync_pulse_20ms) {
         static sma_t sma;
         sma_add(&sma, scanline_counter_20ms);
         scanline_counter_20ms = 0;
@@ -85,7 +82,7 @@ static int scanline_estimator(int sync_level)
             return mode_pd240;
         else if (min_adev == pd290_adev)
             return mode_pd290;
-    } else if (sync_len >= min_sync_length_9ms) {
+    } else if (sync_pulse_9ms) {
         static sma_t sma;
         sma_add(&sma, scanline_counter_9ms);
         scanline_counter_9ms = 0;
@@ -121,7 +118,7 @@ static int scanline_estimator(int sync_level)
             return mode_scottie2;
         else if (min_adev == scottieDX_adev)
             return mode_scottieDX;
-    } else if (sync_len >= min_sync_length_5ms) {
+    } else if (sync_pulse_5ms) {
         static sma_t sma;
         sma_add(&sma, scanline_counter_5ms);
         scanline_counter_5ms = 0;
diff --git a/app/src/main/rs/state.rsh b/app/src/main/rs/state.rsh
index bac29ae..25db770 100644
--- a/app/src/main/rs/state.rsh
+++ b/app/src/main/rs/state.rsh
@@ -20,6 +20,8 @@ limitations under the License.
 static ema_t avg_power;
 static ddc_t cnt_ddc, dat_ddc;
 static fmd_t cnt_fmd, dat_fmd;
+static pulse_t sync_pulse_detector, start_bit_detector;
+static pulse_t sync_pulse_detector_5ms, sync_pulse_detector_9ms, sync_pulse_detector_20ms;
 static int disable_analyzer;
 static int automatic_mode_detection;
 static int debug_mode;
@@ -27,8 +29,6 @@ static int current_decoder;
 static int user_blur, blur_power, free_running;
 static int sample_rate, sync_pos, prev_sync_pos;
 static int maximum_variance, maximum_absolute_deviaton;
-static int minimum_sync_length;
-static int min_sync_length_5ms, min_sync_length_9ms, min_sync_length_20ms;
 static int scanline_length, minimum_length, maximum_length;
 static int vis_length, bit_length, ssb_length;
 static int buffer_length, buffer_mask, buffer_pos;
@@ -38,13 +38,12 @@ static int maximum_width, maximum_height;
 static int freerun_height;
 static int spectrum_width, spectrum_height;
 static int spectrogram_width, spectrogram_height;
-static int sync_length, sync_counter, vpos, hpos;
+static int vpos, hpos;
 static int seperator_counter, seperator_length;
 static int u_sep_begin, u_sep_end, v_sep_begin, v_sep_end;
 static int y_even_begin, y_even_end, y_odd_begin, y_odd_end;
 static int y_begin, y_end, u_begin, u_end, v_begin, v_end;
 static int r_begin, r_end, b_begin, b_end, g_begin, g_end;
-static int sync_buildup_length;
 static int robot36_scanline_length;
 static int robot72_scanline_length;
 static int martin1_scanline_length;