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Yokogawa’s 10th generation digital oscilloscopes offer GHz bandwidth for less money than the competition – and they won’t hog your desktop, either! By PETER SMITH Yokogawa signalXplorer DL9000 Series Digital Oscilloscopes T HE RECENTLY released DL9000 series is the latest in compact digital oscilloscopes from Yokogawa, boasting sampling rates of up to 10GS/s (gigasamples per second) at bandwidths of 1-1.5GHz. According to Yokogawa, conventional products in this bandwidth range have been desktop-sized and quite expensive. Not so the DL9000 series, which packs an impressive array of features into a package measuring 18cm deep and weighing in at only 6.5kg. All four models in the series have four input channels and 213mm highresolution colour LCDs. The DL9140 & DL9140L feature an analog bandwidth of 1GHz with a maximum sampling rate of 5GS/s (2-channel mode) or 2.5GS/s (4-channel mode). 8  Silicon Chip The DL9240 & DL9240L models extend the bandwidth to 1.5GHz and increase the maximum sampling rate to 10GS/s (2-channel mode) or 5GS/s (4-channel mode). Record length for the DL9140 & DL9240 is 2.5M words/channel maximum, whereas the “L” suffixed versions stretch this to a whopping 6.25M words/channel. A custom signal-processing engine pumps data into memory at a maximum effective rate of 2.5 million waveforms per second per channel on the 500ps/div range. First look We test-drove the DL9140 model. We were immediately impressed with the large colour XGA (1024×768 pixels) display, which is bright and razor sharp and would be difficult to better. Considering its quadruple inputs and raft of measurement options, the front panel is relatively uncluttered and doesn’t look intimidating. As with all instruments of this complexity, selections are made and parameters altered via a hierarchical, “soft-key” menu system. Pressing a “top level” function key in the blue-paneled area brings up the relevant on-screen soft menu, which appears as a single bar down the right side of the display to align with the column of unmarked selection keys. The soft menus rarely extend beyond two levels, so once familiar with the instrument’s capabilities, it’s surprising easy to drive. siliconchip.com.au Rotary dials provide for rapid vertical sensitivity and horizontal timebase changes, while the function of the large dial (at panel top) and its associated navigation keys vary according to the last selected menu. A built-in context-sensitive help system is an indispensable part of the overall package. Can’t remember how the options in the “Accumulate” menu work? Easy, just press the HELP button followed by the ACCUM button to bring up the relevant page of the manual! Going deep Deep memory and high-speed sampling coupled with very low latency are undoubtedly the DL9000 series’ strongest points. When record length is less than memory depth, acquisition memory is divided into partitions. Successive records are captured into these partitions (called history memory) with very low latency. In the fastest acquisition mode, up to 1600 records can be captured into history memory with a dead time of only 400ns between acquisitions. Repetitive waveforms can be acquired using the slower accumulate mode, which captures up to 2000 records. Waveforms in history memory can be examined individually, or the sequence replayed in forward or reverse direction at variable speed. A conditional search function allows you to track down signal events based on measurement limits, which can even be correlated between channels. Acquired waveforms can be accumulated over a user-defined period and displayed on-screen using an intensity or colour-grading scheme (called “Dot Density Display”). This works in real time or can be applied retrospectively to history memory. The result is an immediate indication of the frequency and signal-to-noise ratio of signal perturbations. Finding the needle All digital scopes these days include “zoom” capabilities to allow faster review and analysis of selected portions of acquisition memory after signal capture. In zoom mode, the display divides horizontally to include a second expanded view of a portion of the waveform selected in the normal view. The zoom window can be manually scrolled through acquisition memory siliconchip.com.au One of the DL9000 series’ many useful features is its easy-to-drive zoom mode with search. Zoom mode can be brought to bear on history memory (ie, after signal capture) and will help to find that waveform anomaly in quick time. In this example, the “runt” pulse was easy to spot in the normal waveform display but of course this won’t always be the case! (including history memory) using the large rotary knob and various soft controls. Importantly, Yokogawa have included a series of powerful search options that can help to quickly pinpoint the area of interest. Advanced analyses Two additional panes can be opened beneath the normal oscilloscope traces for display of analysis waveforms or XY waveforms. The histogram and trend analysis features are of particular interest and offer a whole new perspective on signal visualisation. For example, signal jitter can be revealed using a time histogram, whereas noise on DC signals can be revealed using a voltage histogram. Trend analysis would typically be used to view the fluctuations of a selected parameter over the long term. Alternatively, the analysis panes can display FFT (Fast-Fourier Transform) calculated waveforms of up to 250k points each using the chosen source channel, centre frequency and frequency span. Math & filters In addition to the four input channel traces, up to eight math traces can be defined and displayed. Functions include filtering, addition, subtraction, integration, “edge count” and “rotary count”. Basic arithmetic functions are performed in hardware and so the results can be displayed in real time. 200MHz & 20MHz analog low-pass filters and a series of selectable digital low-pass filters are also available and again, these operate in real time so they don’t slow down the signal acquisition rate. If the inbuilt math functions don’t do what you want, then the optional “MATLAB tool kit” software can be used to control your scope from within MATLAB or transfer data to MATLAB via the GPIB, USB or Ethernet interfaces. Statistics & other measurements A comprehensive list of signal measurements can be applied to any scope trace. This includes a raft of statistical functions such as maximum, minimum, average, standard deviation, etc. Statistics can be generated on a continual, cycle or historical basis and displayed in the waveform area or at the right side of the screen if the soft-key menu is inactive. Other goodies Go/No Go testing can be set up using January 2007  9 DL9000 Series Highlights • • • • • • • • • • Input channels: 4 Analog bandwidth: 1GHz (DL9140/DL9140L); 1.5GHz (DL9240/ DL9240L) Sampling rate (max): 5 GS/s (2 channels); 2.5 GS/s (4 channels, DL9140/DL9140L); 10 GS/s (2 channels); 5 GS/s (4 channels, DL9240/ DL9240L) Record length (max): 2.5 M word/channel (DL9140/DL9240); 6.25 M word/channel (DL9140L/DL9240L) Fast acquisition rate: 2.5M waveforms/s/ch (max) Vertical sensitivity: 2mV/div Vertical resolution: 8-bit Sweep sensitivity (max): 500ps/div History memory function: Review & analyse up to 2000 of the most recent waveforms Compact & lightweight: 180mm depth, 6.5kg weight. for those that wish to develop custom remote control applications or plug-ins. Applications So where would you use a scope with this level of performance? Here’s a short list of applications suggested by Yokogawa: • Design and evaluation of devices embedded in cellular phones, flatscreen televisions, etc. • Confirming the operation of devices such as FPGAs (Field-Programmable Gate Arrays) and ASICs (ApplicationSpecific Integrated Circuits). • Observation of control signals from microcontrollers and the like, as well as debugging of control firmware. • Troubleshooting and evaluation of communications bus data. Last word a range of user-defined rules, with the results signalled via a TTL-compatible output at the rear of the box. More complex tests can be constructed using “masks” and the free Mask Editor software. Specialised data analysis is also available for the I2C and SPI data buses by ordering the “/F5” option with the scope. This option provides sophisticated triggering on bus states, device addresses, etc, and includes search capabilities. able work, the optional internal 30GB HDD would be a good choice. A printer, mouse and keyboard can also be connected to the front-panel USB ports. The keyboard could be useful for file naming and waveform annotation when working with large sets of data, although we didn’t try this configuration. Using built-in functions, an optional Ethernet interface allows data to be stored and waveforms printed on a network running file and printer sharing. An optional built-in thermal printer is available for portable work. Direct PC connectivity is also possible via a third USB port on the rear of the unit, which is supplied as standard equipment. However, to control the instrument from your PC you’ll need to purchase the optional “Xviewer” software utility. Xviewer also allows you to view saved waveform data and convert binary data to ASCII for use in other applications. A math edition of this software can calculate up to 10 additional waveforms based on saved data and do FFT calculations using up to two million points. A free DLL library is available The triggering options for these instruments are extremely comprehensive and command their own 22-page document – which, by the way, can be downloaded from the Yokogawa website at www.yokogawa.com/tm for those interested. We’re not even going to attempt to describe them in this short review! Product flyers can be obtained from the abovementioned website. Unfortunately, it seems that it’s not possible to download a copy of the user’s manual unless you already own the product. You’ll find the people at Trio Smartcal (the Australian distributors) much more obliging. Check out their website at www.trioelectrix.com.au or phone 1300 853 407 to organise a demonstration. Issues Getting Dog-Eared? REAL VALUE AT Connectivity Getting data in and out of early digital scopes used to be problematic, with floppy drives sometimes being the only option. Thankfully, diskettes have gone the way of the dinosaur and in the case of the DL9000 series, been replaced with dual up-front USB connectors for flash memory as well as dual PCMCIA slots for memory/hard disk drive connection. A total of 32MB of flash memory is available internally for storing waveforms and front-panel settings. An external USB flash memory dongle will instantly improve this rather small offering. For heavy-duty port- Prices Prices for the DL9140 in basic form start at under $15,000 + GST. All models are supplied with four 500MHz passive probes. To utilise the full 1.5GHz bandwidth, you’ll need to order one or more of the optional 2.5GHz active probes. 500MHz differential and 100MHz current probes are SC also offered as optional extras. Keep your copies safe with these handy binders. $13.95 PLUS P & P Available Aust, only. Price: $A13.95 plus $7 p&p per order (includes GST). Just fill in and mail the handy order form in this issue; or fax (02) 9939 2648; or call (02) 9939 3295 and quote your credit card number. 10  Silicon Chip siliconchip.com.au