Emerson Rosemount 3308 Series Reference Manual page 12

Transmitter overview
February 2020
The reflectivity of the product is a key parameter for measurement performance. A high
dielectric constant of the media gives better reflection and a longer measuring range.
See Figure 2-2
Figure 2-2: Flowchart of the Signal Processing
A. Microwave module
B. A/D converter
C. Peak search
D. Peak interpolation
E. Echo identifier
F. Distance filtering
G. Variable calculation
H. Aout handler
I. LCD handler
J. HART
2.1.1 Reference peak
This peak is caused by the transition between transmitter and the tank vapor space or air.
It is used by the transmitter as a starting reference point for distance to the level surface.
2.1.2 Product surface peak
This peak indicates the product level and is caused by a reflection from the product
surface.
2.1.3 Interface peak
This peak indicates the interface level. The peak is caused by reflection from the interface
between an upper product and a bottom product with a relatively high dielectric constant.
This peak is identified when the measurement mode is set to Product Level and Interface
Level or Interface Level with Submerged Probe.
12
for a schematic overview of the signal processing.
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Reference Manual
00809-0100-4308
Rosemount 3308 Series