9.5 Logging Harmonic Summary Data
97
3. When the Save As window appears, use the default name or type in your own file name. Also,
use the browse feature to locate files.
4. Click OK and the data should begin streaming into the specific broadcast data screen at a
rate of once per second. Data is synchronized with the 1 PPS signal from the GNSS receiver
and simultaneously saved to file.
5. Pause or Stop the data stream by clicking the Stop or Pause button. If “Paused”, the data
will accumulate in the computer buffer but not print to the screen. Later, when Pause is
removed, the buffered data will fill the screen. The “Stop This” button will only terminate
the stream of data on top. The “Stop All” button will terminate all data being broadcast
from the 1133A.
6. Use the Filter Data tool to limit the data parameters visible in this window. See Filter Data
Selection Tool on page 91 for more information.
9.5.1
Harmonic Summary Values
RMS THD
, RMS Total Harmonic Distortion, is the rms value of all of the harmonics 2
−
50 and
has the same units, volts or amps. RMS THD is calculated from the following equation:
(9.1)
RM S T HD
=
q
V
2
2
+
· · ·
+
V
2
n
where
V
2
is the 2
nd
harmonic rms voltage, and
V
50
is the 50
th
harmonic rms voltage.
RMS K
is the square of the sum of all of the harmonic energy, including the fundamental (i.e. 1
- 50), with each harmonic multiplied by the the harmonic number. It has the same units as the
signal, i.e. volts or amps. For a clean signal, it will be almost exactly equal to the fundamental
value.
(9.2)
RM S
(
K
) =
p
(
V
1
×
1)
2
+
· · ·
+ (
V
50
×
50)
2
where
V
1
is the fundamental rms voltage and includes all the harmonics up to the 50
th
(
V
50
).
THD F
, Total Harmonic Distortion, is compared to the fundamental and expressed as a percentage.
THD F is calculated from the following:
(9.3)
T HD
(
F
) =
p
V
2
2
+
· · ·
+
V
2
50
V
1
100%
where
V
1
is fundamental voltage, and
V
50
is the highest measured harmonic voltage.
THD T
, Total Harmonic Distortion, voltage is compared to the Total voltage (fundamental plus
harmonics) and expressed as a percent. THD T is calculated from the following:
(9.4)
T HD
(
T
) =
p
V
2
2
+
· · ·
+
V
2
50
p
V
2
1
+
· · ·
+
V
2
50
100%
