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Impulse Noise Model The following presentation was part of a research project at Robert Bosch on automotive Power Line Communications Presenter: Thomas Hogenmüller (Bosch)
AE-BE/EKE-Hogenmüller | 24/04/2013 |
Power Line Automotive Noise Model
Analysis of Impulsive Noise Environment (1) Power Line Automotive Noise Model
AE-BE/EKE-Hogenmüller | 24/04/2013 |
Frequency [MHz] rpm
[min-1] P
ower
dens
ity
spec
trum
[dB
µV]
Frequency [MHz] rpm
[min-1]
Pow
erde
nsity
sp
ectru
m [d
BµV
]
Impulsive noise spectrum at battery mounted in engine compartement
Impulsive noise spectrum at fuse box in rear trunk
Different noise spectra at different locations within car
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Analysis of Impulsive Noise Environment (2) Power Line Automotive Noise Model
AE-BE/EKE-Hogenmüller | 24/04/2013 |
Typical measurement result of a manual switch operation in cars
(e.g. terminal 15 switch operation)
Simulation of the measurment with ISO-pulse
(e.g. test pulse 3a) Am
plitu
de [V
] A
mpl
itude
[V]
Time [µs] Time [µs]
Time [µs] Time [µs]
Freq
uenc
y [M
Hz]
Fr
eque
ncy
[MH
z]
3
Analysis of Impulsive Noise Environment (3)
→ ISO-pulses are not appropriate for simulation of automotive disturbances
Power Line Automotive Noise Model
AE-BE/EKE-Hogenmüller | 24/04/2013 |
On the contrary to manual electrical switches, spark pulses produce disturbances up to high frequencies
Am
plitu
de [V
] A
mpl
itude
[V]
Frequency [MHz]
Time [µs]
Pow
er d
ensi
ty
spec
trum
[dB
µV]
Time-frequency domain Time domain
Am
plitu
de [V
] A
mpl
itude
[V]
Time [µs]
Time domain
Spark plug ignition 2 Spark plug
ignition 1
Trigger signal (Spark plug 1) Spark of plug 2
Spark of plug 1
Spark of plug 2
4
AE-BE/EKE-Hogenmüller | 24/04/2013 |
Power Line Automotive Noise Model
Conclusion of Impulsive Noise Analysis Below 100 MHz:
ISO pulses according to ISO7637 are applicable
Above 100 MHz Spark engine system is mainly responsible for pulse noise.
Furthermore the highest level of pulse noise can be observed during engine idle.
5
AE-BE/EKE-Hogenmüller | 24/04/2013 |
Power Line Automotive Noise Model
Modelling of Impulsive Noise Creation of a configurable impulsive noise model:
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Automotive Impulsive Noise Modelling Power Line Automotive Noise Model
AE-BE/EKE-Hogenmüller | 24/04/2013 |
Aperiodic sequence of impulsive noise
Periodic sequence of impulse pattern
→ Generation of stochastic random variables with Quantiltransformation
Impulse sample duration
Impulse sample period
Impulse amplitude
Impulse period
Impulse duration
Duration [ns] Amplitude [V]
rel.
frequ
ency
2D-Histogram of pulse duration and pulse amplitude
Time duration [µs] re
l. fre
quen
cy Histogramm des Impulsabstands
7
AE-BE/EKE-Hogenmüller | 24/04/2013 |
Power Line Automotive Noise Model
Spark impulsive noise can be defined with 5 parameters: impulse distance, impulse amplitude, Impulse period and Impulse sample distance
which are stochastical values. The fifth parameter Impulse sample period,
is a deterministic value depending on the engine speed
Spark Impulsive Noise (SIN) Parameter
Impulse sample distance
Impulse sample period
Impulse amplitude
Impulse period
Impulse distance
8
AE-BE/EKE-Hogenmüller | 24/04/2013 |
Power Line Automotive Noise Model
Guideline for SIN Simulation 1. Generation of a switch signal depending on engine rotation speed
for identification of a spark event (→ impulse sample distance and impulse sample period)
2. Rectangular signal overlay according to trigger time aperiodic disturbance pulses within one pulse pattern (→ impulse period and impulse distance)
3. Increase of background noise for the duration of an aperiodic impulse noise (→ impulse amplitude)
Impulse sample distance
Impulse sample period
Impulse amplitude
Impulse period
Impulse distance
9
AE-BE/EKE-Hogenmüller | 24/04/2013 |
Power Line Automotive Noise Model
Quantiltransformation Distribution function
Quantiltransformation
Quantiltransformation
X-Values
SNP -Random Numbers
Y-V
alue
s
Gen
erat
ion
unifo
rmly
dis
tribu
ted
rand
om n
umbe
rs
10
AE-BE/EKE-Hogenmüller | 24/04/2013 |
Power Line Automotive Noise Model
SIN Composition Block diagram of spark impulsive noise generator
Impulse sample distance
Impulse sample period
Impulse amplitude
Impulse period
Impulse distance
m-sequence
m-sequence
VTbQ-Trafo Impulse distance
VTbQ-Trafo Impulse period
Impulse amplitude
Sample distance
VTbQ-Trafo sample period
m-sequence
AND
White noise Filter
Spark impulsive noise
11
Simulation of density function
Simulation of measurement data
AE-BE/EKE-Hogenmüller | 24/04/2013 |
Power Line Automotive Noise Model
Flowchart for Impulse Noise Model Set of Measurement data
Combinded data set
Reduced data set
Distribution table
Random number, events are midpoint of class
Random numbers with required density (impulse duration etc.)
Impuls noise signal
Random numbers with additional values
Distribution function
Estimated density function
Analysis
Synthesis
12
Channel model
AE-BE/EKE-Hogenmüller | 24/04/2013 |
Power Line Automotive Noise Model
Frequency Response Frequency range 100 MHz ≤ f ≤ 300 MHz With center frequency f0 = 200 MHz Sample frequency denoted as fa
SIN + additive noise
sender receiver
noise n(t)
Channel H(f,t)=const.
13
AE-BE/EKE-Hogenmüller | 24/04/2013 |
Power Line Automotive Noise Model
Frequency Response Frequency response is simulated with an IIR filter of order 12. Frequency band is normalized to center frequency f0=200 MHz and
sample frequency fa=200 MHz
(a) Frequency response (b) Phase response
measurement measurement
sim model sim model
14
AE-BE/EKE-Hogenmüller | 24/04/2013 |
Power Line Automotive Noise Model
Conclusion ISO pulses are not sufficient to model impulse noise in vehicle Main impulse noise source are spark plugs What’s available:
Measurement data base for power lines Mathematical description of noise FPGA based emulator (for automotive use)
PhD-Thesis of Thorsten Huck is available in German at Shaker publisher for 50 € (I try to find out if the relevant part can be published at IEEE)
15