Table 6:2 - Snr Data Types - Xylem SonTek FlowTracker2 User Manual

software,
Mode
All
Discharge
General
f) SNR is the most important quality control data provided by the FlowTracker2.
SNR
SNR is evaluated against number of quality control criteria and at the end of
Data
each velocity point measurement, the following SNR checks are run in General
Evaluate
mode and Discharge mode.
i). SNR from all beams must be greater than 4 dB for reliable data collection.
ii). Low SNR. If the SNR of any beam is below 4.0 dB, "Low SNR" alert will be
given at the end of point and section measurement.
FlowTracker2 User's Manual (January 2019)
Table 6-2 – SNR Data Types
Reporting Type
Raw Data
Graphical
Moving
Average
Raw Data
Real Time
Mean Point
Review Point
Measurement
Measurement
SNR
Mean Station
Review
SNR
Station
Mean Section
Discharge
SNR
Summary
Mean Beam
Review Point
SNR at Point
Measurement
Measurement
Mean Beam
Review
SNR at
Station
Station
General
Mean SNR
Summary
Description
One second SNR data is displayed for each
beam and color codes based on the beam
number (see
Table 4:4
Moving average is calculated of the one
second SNR data and is graphically displayed
with the raw SNR data.
Instantaneous one second raw SNR data is
displayed with the graphical display.
The point measurement SNR is the mean of
beam 1 and 2 at the point measurement.
Receiver 3 (if installed) is not used in the mean
calculation because we assume the probe is
side-looking (either a 2D or 2D/3D probe), and
only Vx and Vy are of interest. Receiver 3,
which is only used for Vz, is irrelevant.
The station SNR is the mean of all point
measurements at a station.
The discharge summary SNR is the mean of
all the station mean SNR within the section
The point measurement SNR is the mean of
one second SNR data for each individual
beam (2 or 3 depending on probe type) at the
point measurement.
The station SNR is the mean for each
individual beam (2 or 3 depending on probe
type) of all point measurements at a station.
The general summary SNR is the mean of all
individual beam SNRs at all point
measurements.
85
SonTek – a Xylem brand
).