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UQ2062C DSO: Not just special, it’s UNIQUE! Review by NICHOLAS VINEN The UNIQUE UQ2062C is a highly affordable and portable entry-level 60MHz, 500MS/s digital storage oscilloscope with a colour screen and two channels. I t was only a few years ago that a Digital Storage Oscilloscope was an expensive, exotic instrument that few hobbyists could hope to own. Now, DSOs are very affordable, especially for this scope, with a special offer for SILICON CHIP readers. If you quote a special code (see end of review) you can buy this dual channel, siliconchip.com.au 60MHz model with a colour screen for just $695 including GST – about 10% off normal price! The UNIQUE UQ2062C is an attractive, compact unit. With an integrated carrying handle, it is very similar in size and configuration to many of its more expensive competitors, from companies like Tektronix, Rigol and GW. The screen is the same size and resolution as most similar products – a 14.5cm (5.7”) 320x240 quarter-VGA display. It is bright and quite easy to read, although its blacks are not as dark as we’ve come to expect. There is a reason for that, as we will find out later. It is supplied with an IEC power cable, USB cable and two 1.5m 60MHz March 2010  85 1×/10× probes. Each probe comes with an earth alligator clip, compensation adjustment tool and a number of different coloured plastic rings, which make it easier to tell which probe is connected to which channel. It would be nice if the probes came with more accessories, such as earth spring clips but you certainly get enough to start with. While there are cheaper DSOs available but they mostly have monochrome displays. In case you’re wondering why it’s worth spending some extra money to get the colour screen, the primary advantage is that it’s obvious at a glance which waveform is from which input channel. This allows for more flexible use of the display. For example, if you scale both traces to the full height of the screen on a monochrome ‘scope, it can be hard to tell which is which – not so when they have distinct colours. This also applies to the FFT readout and the traces generated from the “math” menu. They can be displayed simultaneously with the raw traces and so have their own colours to avoid confusion. Usability The first thing you’ll notice switching it on for the first time is how fast it boots. It’s under three seconds from turn-on to operation – that’s pretty good for a digital scope. The second impressive aspect is that the screen update rate is excellent. The rapid display refresh makes it feel a lot more fluid than many other low-end DSOs – something that a long time Cathode Ray Oscilloscope user would appreciate. This explains the lowerthan-expected contrast, as contrast and refresh rate are a trade-off with Liquid Crystal Displays. After you have switched it on for the first time, the instruction manual suggests that you manually run the input calibration routine. Once triggered, the procedure is automatic and takes about a minute. This improves the accuracy of measurements by trimming away input offset voltage and scaling errors. Presumably, this procedure should be repeated periodically to keep measurements as accurate as possible. There is no automatic calibration mode, which can be a minor inconvenience. However, sometimes oscilloscopes that do feature automatic calibration can be quite annoying – they always seem to do it right when you’re in the middle of taking a measurement! The controls and menus are easy to learn. Partly, this is because the UQ2062C has less features than other DSOs. This may seem like a big disadvantage but in fact, all the most important features are there. There are even some advanced modes included, such as the ability to record continuous waveform data to memory and play it back later. For the most part, the missing features are those which most entry-level users would not miss. For example, it has Edge, Pulse and Video trigger modes but not Slope, where the trigger is based upon the rate of change of voltage over time. While This shows the display with 1kHz sine waves applied to both inputs, 180 degrees out of phase, after pressing the “auto” button. 86  Silicon Chip Slope mode is theoretically useful, it’s rarely needed. This simplicity turns out to make the UQ2062C surprisingly pleasant to use, since it keeps the number of menu options low. When all you want to do is change the trigger source or acquisition mode – something that you’d be doing frequently – not having to dig through a series of menus and options to find the one you need is great. As a result common tasks involve fewer button presses and knob turns than other digital oscilloscopes we’ve seen. Features We’ve come to expect certain features from a DSO and the UQ2062C doesn’t disappoint. The measurement system is easy to use and all the common measurements you’ll want to take are there – including frequency, RMS voltage, peak-topeak voltage and even channel-tochannel delay. The “math” menu allows you to add, subtract, multiply and divide readings between the two channels as well as perform Fourier Transforms (FFT). You can use the two channels in XY mode, ie, plot them against each other and there are some advanced trigger modes such as alternate trigger, where each channel is separately synchronised. This slows down the update rate but there are situations where it is useful. As for the input system itself (a critical feature in an oscilloscope after all) it’s quite good. The same waves, shown full scale and centred, giving better vertical resolution. Without a colour screen this could be confusing. siliconchip.com.au Sensitivity goes as low as 2mV/division. If you’re using the probes in 10× mode (and for high frequency signal measurements this is a must) then that means it will display 20mV/div which is low enough to show millivolt-level details in the signal. You want a setting that sensitive for observing low voltage signals in detail, such as switch-mode power supply ripple waveforms. Noise performance at the 2mV/div level is also very good – in fact there’s less noise there than is evident on more expensive competitors. Another impressive feature of the input system is the 1-million sample memory buffer. What this means is that you can sample a waveform at high resolution, so that you can see all its details but also retain enough additional samples in memory that you can scroll the window left and right to see what happened before and after the trigger point. Many other DSOs have much smaller buffers – in some cases a tiny fraction (10k samples or 1% as large), which makes it difficult to get both good time resolution and a long history. The sample rate is good too, 500 million per second (500MS/s) if you’re observing a single channel and 250MS/s when using both. That’s more than enough for 60MHz signals. It has the usual acquisition modes – normal, averaging and peak detect along with a 20MHz bandwidth limiting feature to reduce high frequency noise when you’re observing lower frequency signals. Like most DSOs the UQ2062C has an “auto” button which attempts to set up the triggers and scaling to suit whatever you have connected to the input(s). In general it seems to work quite well, usually saving you some hassle fiddling with the settings. Storage & external interfacing There is a USB host port on the front panel into which you can plug a USB flash drive for storing settings, waveform data and screen captures. This is a very handy feature both for computer analysis of captured data and so that you can keep a record of the waveforms you have observed. It’s also handy in case you want to show somebody else what you are seeing on the oscilloscope screen. Data can also be download directly to a computer using the USB port at the rear and the provided cable, however unless you already have a computer at your workbench the flash drive method is more convenient. One problem I’ve found compared to more expensive DSOs is that when you take a screen capture on the UQ2062C, you can’t include any of the measurement data with it, because measurements are displayed in the same area of the screen as the storage menu. Keeping the measurements off the main part of the screen does prevent them occluding the traces, so there is a reason for it but being able to see the measurements in a screen capture is very useful. Window mode shows the whole waveform as well as some detail. This way you can take full advantage of the 1M sample buffer. siliconchip.com.au Another disadvantage of the menu system UNIQUE have come up with is that the menu is permanently visible at the right side of the screen, which limits the display area for the traces. Some other DSOs let you hide the menu when you don’t need it so you can use that screen area for waveform display. This is clearly a trade-off they have decided on to make the menu system simpler – but it would still be nice to have a full screen option. No free lunch By this stage you’re probably starting to wonder what the catch is. As mentioned, this oscilloscope doesn’t have every single feature that more expensive models do but it is certainly good enough for most tasks. The fit and finish of the unit in general is very good and suggests that it has been designed and assembled with care. But a discounted lunch! Normal retail price for the UQ2062 is $770 including GST. Until the end of this month, if you quote the special SILICON CHIP reader code of SCUQ2062C to Trio Smartcal (the Australian distributors of Unique ’scopes) you will get almost 10% off, at just $695. More details? To take advantage of this offer, or simply to find more information on the Unique UQ2062C DSO, visit the Trio SmartCal website: www.triosmartcal. com.au, or call 1300 853 407. SC A 3MHz pulse train shown with its FFT frequency spectrum in red. The rounded corners are due to the bandwidth limiting feature. March 2010  87