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Product Review . . .
GW Instek is a brand
produced by the
Goodwill Instrument
Company of Taiwan.
The model GRS-6032
is an interesting
scope which combines the attributes
of a 30MHz dual trace
analog CRT readout
scope with digital
storage.
GW Instek GRS-6032
30MHz Real Time Digital
Storage Oscilloscope
W
HILE DIGITAL SCOPES have
made great advances over the
last 10 years or so, there is still a place
for capable analog scopes at reasonable
prices. In this GW Instek model, we
have a scope with a foot in both camps
but with many of the operating attrib
utes of an analog scope.
At first sight, the GRS-6032 looks
quite conventional, as an analog scope.
It uses a conventional cathode ray
tube and so it has quite a deep case.
Front panel measurements are 270
x 129mm while the overall depth is
66 Silicon Chip
410mm, including the rear feet which
double as power cord storage. The
CRT screen is 102 x 85mm and it has
a conventional graticule 10 divisions
wide and eight divisions high. Weight
of the unit is 8.5kg.
On the front panel there are 11
knobs, four large and seven small,
and there are 28 pushbuttons, some
of which have associated illuminated
legends. All of these light up in sequence as part of the scope’s self-test
procedure when you first turn it on.
It is not until you start to use it
that you realise that the GRS-6032 is
different from analog scopes in the
past. It is also a CRT readout scope
in which the CRT text takes the place
of much of the labelling on the front
panel controls.
For example, none of the front panel
controls such as the input attenuators
and the timebase switch have any
calibrations, apart from those applying
to their maximum and minimum settings. When you alter these switches,
their settings are shown on the CRT
screen. In fact, virtually every setting
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made via the front panel controls is
indicated in some way on the CRT
screen.
For example, in a typical setup
with both channels in use, the input
attenuator settings will be shown in
millivolts or volts/division (1mV/div
to 20V/div) and the input coupling
will be shown as AC (with a squiggle),
DC (equal symbol) or grounded (with
an earth symbol).
Timebase settings will be shown in
seconds, milliseconds, microseconds
or nanoseconds/division (the last
setting only available in the timebase
multiply mode). Timebase settings
range from 0.5s/div up to 0.2µs/div
and you can add magnification of
x5, x10 and x20 to give a maximum
timebase speed of 10ns/div.
Trigger source settings are shown
as CH1, CH2, line or external while
trigger coupling is shown as AC, HFR
(high frequency reject) or LFR (low
frequency reject). Also shown is trigger
slope (positive or negative and TV sync
(Horizontal or Vertical).
To add to the fun, some of the buttons have double func
tions which
are brought into play either by momentarily pressing them or holding
them down to display the wanted
function on the screen. For example,
for each vertical input channel there is
a button marked “GND” and “Px10”.
Pushing this button briefly, grounds
the relevant channel input (handy to
set trace reference levels) and displays
the earth symbol next to the vertical
attenuator setting at the bottom of the
screen. Holding the button down for
a longer period selects for a x10 probe
and reduces the input sensitivity by
a factor of 10; eg, 10mV/div becomes
100mV/div.
Similarly, underneath the CH2 select button is another button labelled
“Add” and “INV”. Pushing this button
briefly enables you to add the two
channel signals and display them as
one trace. This causes a “+” symbol to
be displayed next to the vertical input
info for CH1. Holding the button down
longer inverts the signal from CH2
and so the waveform displayed is the
difference between the two channel
signals. In this mode, a downwards
arrow is displayed next to the “+” sign
on the screen.
As well as the screen prompts, the
vertical input attenua
tors and the
timebase knob cause a brief beep to be
sounded when you wind the controls
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The rear panel has two BNC sockets, one for the CH1 output and the other for
Z-axis modulation. The D-sockets is the RS232 interface which can be used with
optional software to display and store waveforms on a PC.
beyond their maximum or minimum
settings. You can turn the beep off, if
you wish. By the way, none of the four
large knobs have rotation stops, which
is why the beeper comes in handy.
Horizontal and vertical cursors can
be switched on for period or voltage
measurements and the large knob at
the top lefthand side of the panel is
used for fine or coarse movements
of the cursors, either separately or as
a pair.
By now then, you should have
the strong impression that this is an
easy-to-use analog scope, with strong
emphasis on the CRT-readout (ie, text
on screen).
Digital storage
Digital storage operation is brought
into play by the five blue buttons on
the control panel. Selecting “storage”
switches over to digital mode. The
sample rate is now displayed at the top
of the screen (up to 20 megasamples/
sec) and a vertical trigger cursor is
shown as well. Its position can be
moved across the screen by the fine/
coarse knob.
The menu button has five functions.
First, you can turn smoothing on or
off. Smoothing on removes some of
the “jaggies” on a typical digital scope
waveform and also changes from a dot
display to one with the dots connected.
Second, you can use Average mode
whereby waveforms are averaged to
remove the effects of random noise.
You can select 2, 4, 8, 16, or up to 256
waveform averages. Naturally it only
works with repetitive waveforms (eg,
sinewave) and it takes quite a while
to produce the higher average setting.
Third, you can select an interpolation mode which can be handy when
you are displaying magnified data
(brought into play by using timebase
magnification). Fourth and fifth, you
can save and recall up to nine reference waveforms.
Other buttons used in the digital
mode are run/stop, single (trigger)
and utility. The last button allows you
to load factory default or create your
own default panel settings, to turn the
beeper on or off and finally to set the
RS232 baud rate (300, 1200, 2400, 4800
or 9600) for the serial interface.
Overall, the GRS-6032 has been
thoughtfully designed and the clever
use of the CRT readout text really
does make it quite straightforward to
use.
It comes complete with two switchable x1/x20 60MHz probes and a quite
well-written and succinct instruction
manual.
It is priced at $1499.30 including
GST. For further information on this
and other GW Instek oscilloscopes,
contact the Australian distributors,
Emona Instruments Pty Ltd, phone
1800 632 953 or via the web at
SC
www.emona.com.au
December 2002 67
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