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cord,
~
T
=
sampling interval), to 9999
seconds, with a resolution of
~
T. It
allows data collection to be offset in
.
time with respect to the trigger. Also,
in all trigger modes, the start of chan-
nel B can be offset in time with re-
spect to the start of channel A by 0 to
9999 seconds, (resolution,
~
T), allow-
ing measurements on systems with
delay.
Weighting Functions Available
Each channel of the 2032 can be
independently set to have a flat, Han-
ning, transient, or exponential weight-
ing function. The Hanning window is
used primarily with continuous sig-
nals, while the flat, transient, and ex-
ponential windows are used with tran-
sient signals, (the flat or transient
window for the transient itself, and
the exponential window for a system
response). With the transient and ex-
ponential windows, the start of the
window with respect to the beginning
of the record and the window width
are user-definable. The resulting win-
dows are displayed on the 2032 dis-
play screen, superimposed on the re-
corded data, (Fig.6).
Averaging of Data
The 2032 can average up to 32 767
spectra in exponential, linear, or for
single channel operation only, peak
(hold max.)averaging mode. Stable av-
eraging algorithms are employed, such
that the results displayed are always
correctly scaled for read-out, and the
number of averages is selectable to be
any integer value from 1 through
32 767. The amount of overlap be-
tween averaged spectra is also selec-
table to be 0%, 50%, 75%, or maxi-
mum. Where the 2032 cannot achieve
the selected overlap, (for example, due
to its real-time frequency), an auto-
matic warning is given.
The 2032 automatically rejects data
influenced by an input overload from
Fig.6. Examples
of
transient,
(upper
trace),
and
exponential,
(lower
trace), windows superimposed on re-
corded data
4
an average. Additionally, a manual ac-
cept mode allows data to be visually
inspected prior to its entry into an
average.
Signal Enhancement Mode
In addition to the averaging func-
tions mentioned previously, the 2032
has
~
signal enhancement mode. This
allows successive time domain records
to be averaged on the receipt of a trig-
ger. The result is that signals synchro-
nous with the trigger are enhanced in
the averaged record, while asynchro-
nous signals, for example background
noise, are averaged out, (Fig.7). From
1 through 32 767 records can be linear-
ly or exponentially averaged, with an
internal or an external trigger source.
Storage of Data on the 2032
The 2032 is equipped with a memo-
ry where one complete set of results,
time functions, and the measurement
setup can be stored. The stored func-
tions will depend on the mode of oper-
ation of the 2032, but all functions
which can be calculated from the in-
put data can also be calculated from
the stored data.
The stored data can be used to
"equalize" a frequency response or im-
pulse response. Here the amplitude
and phase difference between the two
measurement chains entering the 2032
are analyzed and stored. This infor-
mation is then used by the 2032 to
correct the transfer function etc., for
differences in the measuring chains,
with
the
equalized
result
being
displayed.
Display of Data
Display of data takes place on the
2032's built-in 12" raster scan display
screen. The display format is selec-
table between single and dual trace,
with single trace formats being further
selectable between full screen and half
screen with the measurement setup,
Fig. 7. Instantaneous, (upper trace), and
enhanced, (lower trace), spectrum.
The background noise is very much
reduced in the enhanced spectrum
(see Fig.3). Each trace is fully anno-
tated with the display setup label, the
display setup parameters, the number
of averages performed, the measure-
ment setup number used, and the cur-
sor values. Further annotation can be
added via two text strings, whereby up
to 100 characters each of alphanumer-
ic text can be entered on to the display
screen, (Fig.8). In a dual trace display,
the display setup can be independent-
ly chosen for each trace.
When frequency domain data is dis-
played, the x-axis is selectable to be
linear with 401 or 801 lines resolution
or logarithmic over 2 decades. For
time domain data, the x -axis is linear
with 512, 1024, or 2048 samples reso-
lution. In the amplitude probability
mode, the x-axis is linearly scaled
from minus to plus the maximum
peak input voltage with 32, 64, 128,
256, or 512 amplitude intervals.
The y-axis can be linearly or loga-
rithmically scaled. With linear scaling,
full scale can be set from 1 x 1
o-
24
to 1
x 10
24
V, V
2
,
V
2
/Hz, V
2
s/Hz, U, U
2
,
U
2
/Hz, U
2
s/Hz, (where U denotes user-
defined engineering units). With loga-
rithmic scaling, full scale can be from
-500 to
+
500 dB in 0,1 dB steps with a
range of 10, 20, 40, 80, or 160 dB. In
amplitude probability mode, linear
scaling in
%
is used.
The Cursor Functions
The 2032 has six cursor functions,
namely the Main Cursor, used for
reading values from the 2032 display,
the Harmonic Cursor, used for identi-
fying harmonics, the Side band Cursor,
used for identify sidebands, the Delta
Cursor, used for measuring across a
band of lines or samples, the Mask
Cursor, used with Nyquist or Nichols
plots to mask unwanted information,
and the Reference Cursor, used to ref-
erence all readings to one line or sam-
ple, (see Fig.9).
Fig.B. Example of use of the text line for
increased annotation
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