As a self-calibrating 2-channel PC-hosted oscilloscope, Link Instruments's DSO-8502 runs in conjunction with virtually any Windows PC, including Windows XP and Win 2000. The company also indicates initial testing with Windows Vista has proved successful.
Regardless of which version of Windows your host platform uses, and at whatever processor clock speed you may have, the speed of the PC doesn't significantly impact the performance of this battery powered 100-MHz scope module. The hardware's dual 8-bit A/D (analog-to-digital) converters do the heavy lifting, with the PC simply used as a display and for a user interface. Your PC need only be is fast enough, and equipped with sufficient RAM, to run Windows properly.
The 8-bit hardware data-acq is what acquires data at up to 500 Msamples/s and feeds the 1-Msample buffer. Only when the deep-memory buffer is full is acquired waveform data transferred to your host PC across a USB 2.0 (Universal Serial Bus) link.
Optional Libraries
Although Link Instruments provides its ready-to-go FrontPanel software (referred to in the company's press release, on the left), you can also write your own. Optionally, both National Instruments LabVIEW VI drivers or DLLs can be used. The DLL/LabVIEW library is priced at $300.
Regardless of what ultimate Windows environment you create or choose, the DSO-8502's Windows software lets you organize the display with color-coding and hooks for data management such as file storage and file loading. Naturally, you can also share files and export them to other Windows applications.
The system also provides what link refers to as channel history, which is similar to a benchtop scope's persistence mode. In use, the DSO-8502 software automatically saves and displays previous captures, and each capture is color-coded based on the time of trigger, with the oldest traces fading to white.
Up to 27 captures can be displayed simultaneously. Previous captures can also be displayed, and you can process these waveforms with FFTs (fast Fourier transforms) for spectral analysis, or do X-Y plots. There are also math functions.
Production Line Pass/Fail Use
You can also use the DSO-8502 for Pass/Fail testing. In addition to data logging on every capture, data can be logged to disk automatically based on whether a Pass or Fail indication occurs; that can be handy in an industrial setting, in the hands of semi-skilled production personnel.
Unique colors can be applied to each channel trace. Color can also be used to code functions, horizontal and vertical cursors, as trigger position. Color can also be selected for text, background, and grids. Cursor measurements are also coded to match the channel color.
When the DSO-8502 is used as a spectrum analyzer, you can control and view both frequency-domain and the time-domain display windows simultaneously. Alternatively, a pair od FFT channels can be viewed simultaneously. What's more, unlike swept spectrum analyzers that demand repetitive signals, the DSO-8000 can also analyze a single-shot event.
In use, the system's frequency range, the FFT algorithm chosen, and the degree of spectral resolution and vertical/horizontal size is set using the FrontPanel software. The FFT screen also includes its own set of cursors that indicate magnitude and frequency.
Automatic Set-Up
The FrontPanel software also supports an Auto-Setup mode. Using Auto-Setup, the software analyzes incoming data and sets the oscilloscope using data analysis routines. Although that's done automatically, you can also fine tune any or all of the scope's parameters.
There's also a zoom-and-scroll mode. Normally, the display shows the entire recorded waveform or waveforms. However, you can also zoom up to 50X in order to examine signal details. Similarly, the scroll function lets you sort through long data records. While doing this, a special locked all-channel zoom keeps all analog waveforms synchronized.
By zooming and scrolling, and then measuring using on-screen cursors, pulse width and channel-to-channel timing can be compared at different sections of data streams. This feature permits identification of time-varying problems. Moreover, the scope's deep memory supports analysis of jitter from the beginning of a record to its end.
At the module itself, you get choice of AC or direct (DC) coupling, with 1-Mohm input-impedance channels. The scope also provides a TTL-compatible trigger input channel, as well as a Trigger Out port and a TV trigger. Triggering can be set to occur at a waveform's rising or falling edges, at a set pulse width and count, or at pulse widths and pulse counts.
Using a 1X probe, the scope operates with a 50-mV to 50-v FS (full scale) input. Vertical range is ten divisions on-screen.
The DSO-8502's timebase can be set to operate from 20-seconds/division to as fast as 2-ns/division. Sample rates across that range extend from 5-samples/s to as fast as the 500-Msample rate. Significantly, channel-to-channel skew is held to less than 1-ns.
A Differential Probe
Notably, Link also offers a differential probe. Dubbed the ADF25A High Voltage Differential Probe it should prove useful for getting into switching supplies, motor control circuits, and other circuits where you would want to measure voltages that are floating with respect to ground. An ADF25A exhibits an input-Z of 4-MΩ from each side to ground, and has an 8-Ω impedance between inputs.
The less-than-$400 ADF25A will accept up to 1-kV AC (rms) or ±1.4-kV DC differential and common-mode levels. The ADF25A probe can also withstand this 1000-V common-mode on any attenuation range without damage.
That capability can let you safely observe signals superimposed on much higher common-mode voltages. You can, for example, look at low-amplitude signals that may be on devices operating at several hundred volts above ground. The probe also meets, and is approved for, IEC1010 Category III specs.
Multiple ADF25A probes can also be used to probe systems with more than one channel. The use of additional probes on the scope, with its common timebase, permits the viewing of multiple floating waveforms such as three-phase AC motor or transformer measurements.
Significantly, the probe can be powered from four AA batteries (or from an external 6-V source that can deliver about 60-mA). Because the output and power connections are ground-referenced and separated from the probe's differential inputs, an isolated power supply isn't needed.
Click here for a table of specs.
For more details, ontact Todd Schreibman at Link Instruments, Inc., 17a Daniel Road East, Fairfield, New Jersey 07004. Phone: 973-808-8990. E-mail: sales@linkinstruments.com
Link Instruments, 973-808-8990, www.linkinstruments.com
