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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 www.siliconchip.com.au 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 www.siliconchip.com.au 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