Image Processing Reference
In-Depth Information
RBW : 1 MHz
VBW : 3 MHz
SWT : 100 ms
Defector : RMS
Trigger mode : Free run
Trace
RBW : 1 MHz
VBW : 3 MHz
SWT : 100 ms
Defector : RMS
Trigger mode : Free run
Trace
dBm
dBm
: Max hold
: Max hold
Ref level: -20 dBm
Ref offset : 0,0 dB
Ref level: -20 dBm
Ref offset : 0,0 dB
-20
-30
-40
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
WISA
WISA
GSM
1800
-50
-60
-70
-80
-90
-100
-110
-120
GSM
900
GSM
1800
GSM
900
Arc
welding
noise
3000 MHz
3000 MHz
0
0
Analyzer
Start frequency : 39,1182 MHz
Start frequency : 29,7298184 GHz
: 2,93386364 GHz
Start frequency :
39,1182 MHz
1,50605002 GHz
Stop frequency : 2,97298184 GHz
Span
Span
Analyzer
Center frequency : 1,50605002 GHz
Center frequency :
: 2,93386364 GHz
Arc welding
Defector : RMS
Trigger mode : Free run
Trace
RBW : 1 MHz
VBW : 3 MHz
SWT : 100 ms
Detector : RMS
Trigger mode : free run
Trace : Max hold
RBW : 1 MHz
VBW : 3 MHz
SWT : 100 ms
dBm Rel level : 20 dBm
dBm Rel level : -20 dBm
Rel offset : 0.0 dB
Rel Offset: 0.0 dB
: Max hold
-20
-20
-30
-30
WISA
WISA
-40
-40
GSM
1800
-50
-50
GSM
1800
UMTS
2100
UMTS
2100
-60
-60
-70
-70
-80
-80
Foil
welding
noise
-90
-90
-100
-100
-110
-110
Trace : Max hold
-120
-120
3000 MHz
0
3000 MHz
Start frequency : 0 Hz
Center frequency : 1.5 GHz
Start frequency : 3 GHz
Span : 3 GHz
Start frequency : 0 Hz
Center frequency : 1.5 GHz
Stop frequency : 3 GHz
Span : 3 GHz
Analyzer
Foil welding
Freq. spectrum: without
With welding
FIGURE .
Frequency spectrum plots of electromagnetic noise of industrial welding equipment.
byalaptopPCwithanIEEE.gWLANcommunicatingtoanaccesspoint(AP)transmitting
at Mb/s on channel at mW. Measurements were repeated at several distances (
d
., ,
and m) between the AP and the WISA BS, and were taken over , WISA messages each.
Figure . (middle) shows the increased number of WISA retransmissions due to the WLAN
interference.
The effective data rate of the WLAN was reduced from . MB/s in the interference-free case to
. MB/s
=
respectively.
In the second scenario, a Bluetooth-equipped laptop continuously transmits toward a Bluetooth
AP at mW and m distance (Figure ., bottom) shows that the effect of Bluetooth interfer-
ence on WISA retransmissions is much smaller than the effect of WLAN interference. In the
converse direction, the Bluetooth data rate was reduced from . to . kB/s by the interference
from WISA.
Further work on WISA is under way on implementing WLAN options, which allow either for
the downlink or all links a blacklisting of WLAN channels. As the dominant influence on WLAN
is the continuous downlink (compare Figure . top and middle), just blacklisting the down-
link is improving the WLAN statistic significantly, see Figure . bottom, where the downlink
has been in a wire to verify uplink influence. This statistic is already very close to the reference
measurement (top).
It has to be noted that generally the disturbance range of a system, outside which, e.g., fre-
quency can be reused, is significantly larger than the safe operation range. The disturbance range
of a wanted system also varies with respect to a victim system, so it is not a wanted system
property only.
(
d
=
. m
)
,.MB/s
(
d
=
m
)
,and.MB/s
(
d
=
m
)
