diff --git a/libraries/Filter/examples/Derivative/Derivative.pde b/libraries/Filter/examples/Derivative/Derivative.pde
index 9247368b8f..4ab1733c2b 100644
--- a/libraries/Filter/examples/Derivative/Derivative.pde
+++ b/libraries/Filter/examples/Derivative/Derivative.pde
@@ -1,6 +1,6 @@
 /*
-	Example sketch to demonstrate use of DerivativeFilter library.
-*/
+ *       Example sketch to demonstrate use of DerivativeFilter library.
+ */
 
 #include <FastSerial.h>
 #include <AP_Common.h>
@@ -10,23 +10,23 @@
 
 #ifdef DESKTOP_BUILD
 // all of this is needed to build with SITL
-#include <DataFlash.h>
-#include <APM_RC.h>
-#include <GCS_MAVLink.h>
-#include <Arduino_Mega_ISR_Registry.h>
-#include <AP_PeriodicProcess.h>
-#include <AP_ADC.h>
-#include <AP_Baro.h>
-#include <AP_Compass.h>
-#include <AP_GPS.h>
-#include <Filter.h>
-#include <SITL.h>
-#include <I2C.h>
-#include <SPI.h>
-#include <AP_Declination.h>
+ #include <DataFlash.h>
+ #include <APM_RC.h>
+ #include <GCS_MAVLink.h>
+ #include <Arduino_Mega_ISR_Registry.h>
+ #include <AP_PeriodicProcess.h>
+ #include <AP_ADC.h>
+ #include <AP_Baro.h>
+ #include <AP_Compass.h>
+ #include <AP_GPS.h>
+ #include <Filter.h>
+ #include <SITL.h>
+ #include <I2C.h>
+ #include <SPI.h>
+ #include <AP_Declination.h>
 Arduino_Mega_ISR_Registry isr_registry;
-AP_Baro_BMP085_HIL      barometer;
-AP_Compass_HIL     compass;
+AP_Baro_BMP085_HIL barometer;
+AP_Compass_HIL compass;
 SITL sitl;
 #endif
 
@@ -37,25 +37,25 @@ DerivativeFilter<float,11> derivative;
 // setup routine
 void setup()
 {
-	// Open up a serial connection
-	Serial.begin(115200);
+    // Open up a serial connection
+    Serial.begin(115200);
 }
 
 static float noise(void)
 {
-	return ((random() % 100)-50) * 0.001;
+    return ((random() % 100)-50) * 0.001;
 }
 
 //Main loop where the action takes place
 void loop()
 {
-	delay(50);
-	float t = millis()*1.0e-3;
-	float s = sin(t);
-	//s += noise();
-	uint32_t t1 = micros();
-	derivative.update(s, t1);
-	float output = derivative.slope() * 1.0e6;
-	uint32_t t2 = micros();
-	Serial.printf("%f %f %f %f\n", t, output, s, cos(t));
+    delay(50);
+    float t = millis()*1.0e-3;
+    float s = sin(t);
+    //s += noise();
+    uint32_t t1 = micros();
+    derivative.update(s, t1);
+    float output = derivative.slope() * 1.0e6;
+    uint32_t t2 = micros();
+    Serial.printf("%f %f %f %f\n", t, output, s, cos(t));
 }