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LeCroy challenges on processing power with 6-GHz scope range

Within its latest range of WavePro digital oscilloscopes, the 700Zi series, LeCroy has created three distinct categories: general-purpose oscilloscopes, serial data analysers, and disc drive analysers. The instruments have real-time bandwidths of 1.5, 2.5, 3.5, 4 or 6 GHz (2.5 – 6 GHz for the serial analysers, and 3.5 or 6 GHz for the disc drive analysers), with sampling rates of 20 Gsamples/sec on all channels– all are 4-channel units– with 40 Gsample/sec available with interleaving. As with previous LeCroy oscilloscopes, long record length is a feature. 10 or 20 Mpoints/channel is standard, and you can extend this to 128 Mpoints/channel. All channels have both 50-Ω and high-impedance (1 MΩ) inputs that span the complete real-time bandwidth – you do not need to connect a highimpedance adapter to use a passive probe.

As with other recent oscilloscope announcements, LeCroy sees measurement speed and responsiveness of the instrument as a key competitive area. The company’s claim for these products is that they are 10 to 20 times faster than comparable oscilloscopes in processing waveforms, and therefore in responsiveness of updating the display following a change you make to the measurement settings. The company calls its processing architecture X-Stream II; it uses variable waveform segment lengths to improve CPU cache memory effi ciency, producing a better result than the approach of processing a full-length waveform in one pass. The CPU is an Intel Core 2 Quad with up to 8 Gbytes of RAM, running Windows Vista. As well as more responsive behaviour, the oscilloscopes achieve up to 750,000 measurements/ sec. With a direct connection (using an optional interface card) to the internal PCI Express X4 bus, the scopes can transfer data at up to 500 Mpoints/sec (you can also use 100 Mbps or Gigabit Ethernet connections, with slower data transfer rates–even Gigabit is 20-times slower than the LSIB interface card, the company asserts).

An advanced triggering package (TriggerScan) operates alongside features such as pulse-width triggering down to 200 psec, and pattern triggers that operate on 80-bit sequences up to 3.125 Gbps; you can add options that provide the software to trigger and analyse waveforms from a wide range of standard bus formats. TriggerScan uses fast hardware detection of signal anomalies, then writes those waveforms to the screen in persistence mode–this, the company says, is a better approach to capturing very rare events in long waveforms, and maintains its performance with long capture times or high sampling rates. You can defi ne a set of trigger conditions that might mark out the feature that you are searching for, and the instrument will cycle through them with a preset dwell time.

The instrument hosts a set of processing tools that run on the internal PC, including a spectrum-analysis package that emulates many of the features of a spectrum analyser. For any feature not in the standard software tool set, you can have the instrument run a script that executes the function in MATLAB and returns the result to the screen. The display is a 15.3-in. WXGA, and you can have a second identical screen that mounts on top of the standard instrument to view, for example, signal-processing programs while still viewing waveforms on the main screen.

Serial data and disc-drive analysers are variants of the standard instruments that have extra features focussing on fast serial data streams. For example, you can annotate an eye diagram with contours representing constant-biterror- rates, for better insight into the margins your design is achieving. Skew-correction is also available to implement cable-de-embedding.

As with most major oscilloscope releases, the 700Zi series has an accompanying set of new high-performance probes; they have low noise levels that suit them to making precise jitter measurements; and they can handle offsets of ±4V, with ±3V common-mode control, to handle a wide range of measurement scenarios. Example pricing for the 700Zi series ranges from €21,400 for a base 1.5-GHz model, to €54,900 for a 6-GHz model, rising to €63,900 for the fastest version with the discdrive analysis package.

LeCroy, www.lecroy.com