6 | Analog and Frequency Inputs
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DDU 10
Bosch Motorsport
6.2.5 Digital filter details
DDU 10 uses A/D converter oversampling and digital filtering to recording rate.
Digital filters eliminate ‘out-of-band’ noise
Cut-off frequency automatically adjusted to recording rate
Example:
– 100 Hz recording rate (10 ms)
– <40 Hz pass band (>99 %)
– >50 Hz stop band (<1 %)
Linear phase – no signal distortion
0
500
1000
1500
2000
2500
3000
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
Abtastwerte (roh)
Wert
10000Hz Abtastrate
0
5
10
15
20
25
30
-1.5
-1
-0.5
0
0.5
1
1.5
Abtastwerte (gefiltert)
Wert
100Hz Abtastrate
0
5
10
15
20
25
30
-1.5
-1
-0.5
0
0.5
1
1.5
Abtastwerte (dezimiert)
Wert
100Hz Abtastrate
Sensor signal with noise
Recorded signal 100Hz
(unfiltered)
Recorded signal 100Hz
(filtered)
Latency compensation – no filter delay in recorded data
– Filtering is (smart) averaging over several samples
– Filtered signal is delayed with respect to real time signal
