T E C H N O L O G Y
P U L S E
B U R S T
R A D A R
Pulse
PULSAR is a top-mounted, downward-looking pulse burst
radar operating at 5.8 GHz (Europe) or 6.3 GHz (North
America). Unlike true pulse devices (ECLIPSE Guided Wave
Radar) which transmit a single, sharp (fast rise-time) wave-
form of wide-band energy (Figure 1), PULSAR emits short
bursts of 5.8 or 6.3 GHz energy (Figure 2) and measures
the transit time of the signal reflected off the liquid surface.
Distance is calculated utilizing the equation Distance equals
two (Distance
=C
×
Transit Time/2),
then developing the
level value by factoring in tank height and sensor offset
the Speed of light multiplied by the transit time divided by
Figure 1
Pulse Burst
information (Figure 3). The exact reference point for dis-
tance and level calculations is the sensor reference point
(bottom of an NPT thread, top of a BSP thread, or face of
a flange).
The exact level measurement is extracted from false target
reflections and other background noise via the use of
sophisticated signal processing. The new PULSAR circuitry
is extremely energy efficient so no duty cycling is neces-
sary to accomplish effective measurement. For this reason
PULSAR can track high rates of change (180 inches [450 cm]
per minute) that were heretofore impossible with existing
loop-powered radar transmitters.
1 ns
500 ns
Distance = c
×
(time
÷
2)
Figure 2
E Q U I V A L E N T
T I M E
S A M P L I N G
ETS, or Equivalent Time Sampling, is used to measure the
high speed, low power EM (electromagnetic) energy. ETS
is a critical key in the application of Radar to vessel level
measurement technology. The high speed EM energy
(1000 ft/µs) is difficult to measure over short distances and
at the resolution required in the process industry. ETS
captures the EM signals in real time (nanoseconds) and
reconstructs them in equivalent time (milliseconds), which
is much easier to measure with today’s technology.
ETS is accomplished by scanning the vessel to collect
thousands of samples. The round-trip event on a 65-foot
(20 meter) tank takes only 133 nanoseconds in real time.
After it is reconstructed in equivalent time it measures
200 milliseconds.
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MAGNETROL [ MAGNETROL INTERNATIONAL, INC. ]
