Plug-in digitizer boards can morph your desktop PC. They can convert a PC into a lab-grade data-acquisition system, a versatile piece of test gear, or even a radio receiver.
PCI, PXI (PCI EXtensions for Instrumentation), VXI (VME eXtensions for Instrumentation), and cPCI (CompactPCI) board-level subsystems can serve applications ranging from benchtop oscilloscope replacements to medical imagers to software-defined radios. Digitizer products are typically supplied with sophisticated display, processing, and analysis software and firmware, too.
Here's a round-up of some of the most significant such products reviewed recently at eeProductCenter.
Gage Applied Technologies’s Octopus family of multi-channel digitizers are modular single-slot PCI bus boards. You can set them up with two to eight digitizing channels, with a choice of 12-bit or 14-bit A/D (analog-to-digital) conversion resolution. They’re priced at a cost of less than $1000/channel.
In operation, an Octopus’s input channels operate at sampling speeds up to 125-Msamples/s/channel. That’s backed up by as much as 4-Gbytes of on-card acquisition memory.
On-board FPGA (field programmable gate array) options are also available for Octopus digitizers. Gage's eXpert FPGA-based subsystems implement FIR (finite impulse response filtering), FFT (fast Fourier transform) spectral analysis, signal averaging, and peak detection. The eXpert FPGAs let you perform on-the-fly data analysis.
The digitizers are also compatible with Gage's GageScope oscilloscope software. Running out-of-the-box under Windows, it lets you acquire and analyze signals. If you so choose, Gage’s SDKs (software development kits) support programming in C, C#, MATLAB, LabVIEW, or LabWindows/CVI, too.
Click here for a previous eeProductCenter review, and additional information on Gage’s products.
Or, search www.eeProductCenter.com for Article ID: 174910167.
Another vendor rolling out multi-channel digitizer boards is Interactive Circuits and Systems, Ltd. ICS’s ICS-645D is a 32-channel 5-Msample/s data acquisition card (8-channel and 16-channel versions are also available).
The ICS-645D not only handles A/D conversion, programmable gain, and anti-alias filtering resources in one full-length PCI card, but also eliminates the need for auxiliary clocking by including a programmable clock source on-board.
The gain and filtering blocks also sidestep the need for signal conditioning circuitry ahead of A/D conversion. The A/D stages are based on Analog Devices AD9260 delta-sigma chips.
Fast Data Paths
One of the primary concerns in the design of a high channel-count high-speed A/D card is the problem of moving data back to the host processor or recorder. The ICS-645D addresses this problem with two high-bandwidth data paths for communication with host systems.
The board gives you two high-speed data routes (PCI 64/66 or FPDP II; front-panel data port) back to your host system.
The 64/66 PCI interface provides data rates in excess of 400-Mbytes/s (sustained aggregate rate—not burst rate). For its part, the FPDP II port provides a dedicated connection to collect data from multiple cards. It also eliminates operating-system interrupt latencies.
The ICS-645D also provides up to 16-Mbytes of on-board storage, permitting it to tolerate unpredictable interrupt latencies encountered in non-realtime operating systems.
The ICS-645D, in an 8-channel iteration, is priced at about $14,000 each in quantities of 1-9. A 16-channel version costs about $2000 more. A 32-channel version is priced at $18,000.
Click here for a previous eeProductCenter review, and additional information on ICS’s product.
Or, search www.eeProductCenter.com for Article ID: 174401078.
A high-res PXI plug-in that’s suitable for RF and some ATE (automatic test equipment) applications comes from board maker Acqiris. It has 10-bit 4-Gsample/s digitizers with 3-GHz input-bandwidth specs.
Acqiris’s single-slot digitizers are based on proprietary A/D converters. A pair of ASICs (application-specific integrated circuits) integrates signal conditioning, amplification, and interleaving. Another ASIC enhances data converter performance through the distribution of accurate timing signals. It also helps synchronously pass acquired data to on-board memory.
Acqiris’s dual-channel Model DC152 and single-channel DC122 digitizer boards are compliant with both PXI and cPCI standards. These boards are suitable for in synthetic instrumentation systems.
In synthetic instrumentation systems, these boards can displace conventional wideband oscilloscopes. They can also serve as the front-ends for RF power meters, multimeters, and frequency counters. A variety of front-end mezzanine modules tailor the boards for synthetic instrumentation applications.
Like Gage’s wares, Acqiris’s digitizers are supported with the company's existing AcqirisLive and AcqirisMAQS software. You aren’t limited to Windows platforms, however. You can run the company’s scope executables under Linux, or Wind River’s realtime VxWorks. Acqiris supplies drivers for integration into production test and ATE gear.
These 3U-sized PXI digitizers, with their 3-GHz specs, are not your average low-bandwidth PC plug-insand that’s reflected in their price tags. A DC122 is priced at about $$15,500 sans front-end modules. A high-frequency module can add about $1000 to that.
A basic DC152 is priced at about $17,500. It can be fitted with a standard front-end module for a bit less than $2000 additional.
Click here for a previous eeProductCenter review, and additional information on Acqiris’s products.
Or, search www.eeProductCenter.com for Article ID: 174402542.
ZTEC Instrument also offers a number of board-level digitizers. These give you DSO (digital storage oscilloscope) capabilities in PCI and PXI form-factors.
A ZT431 can be used in either single-channel or multi-channel oscilloscope applications. With two channels, a ZT431 can give you simultaneous sampling at 100-Msamples/s, or interleaved sampling at double that rate.
ZTEC’s 12-bit 90-MHz PXI ZT431, for example, is a less-than-$5000 3U-sized scope plug-in based on company's UIP (Universal Instrument Platform). All UIP ZTEC boards use the same hardware core. The modular architecture lends itself to high channel-count applications with tight signal sync.
Synchronizing Multiple Boards
Multiple plug-ins can also be synchronized using local timing and trigger buses. PLL (phase locked loop) and star triggering provides sync where multi-instrument timing is key.
ZTEC also offers a $2200 option that provides a better frequency standard, as well as improved PXI star triggering. The option supports the addition of synchronized chasses to your test system.
If fitted with a $3200 GPS (Global Positioning System) satellite receiver option, the ZT431’s reference can be synchronized more tightly, with triggers tagged to within 25-ns of a UTC (Universal Coordinated Time) reference.
If you need greater bandwidth and higher resolution, ZTEC’s ZT410 family of DSO boards also operate in PXI, PCI, and VXI systems and are available in both 14-bit and 16-bit 250-MHz versions.
The ZT410 family combines conventional benchtop oscilloscope features with higher precision and deep memory. You also get low noise, low distortion, and low drift, providing the dynamic range needed for more demanding measurements.
Acquisition modes include Normal, Average, Envelope, Equivalent-time, and Interpolated-time, with 32-ksamples the maximum waveform size available. Triggering is bench-like as well. The trigger source can be derived from either channel, and you can also use an external TTL-compatible trigger.
You can also trigger from a pattern (matching true or false), or from software. You can also use a sync star trigger, which is TTL-compatible from a PXI backplane or PCI Timing Expansion Connector.
Both 14-bit ZT410-20 and 16-bit ZT410-50 boards are priced at less than $5500 each. Upgrades to a 16-Msample memory will add about a $1000 to that figure.
The ZT412-20 and ZT412-50 VXI versions are priced at about $10500 for a 2-Msample memory option and at about $12500 for a 32-Msample memory option.
Click here for a previous eeProductCenter review of the Z410 boards.
Or, search www.eeProductCenter.com for Article ID: 174901146.
Click here to read about ZTEC’s 90-MHz boards.
Or, search www.eeProductCenter.com for Article ID: 169600355.
If you need even deeper memory in your digitizing system, check out Ultraview Corp.’s AD8-1500DMA board. The company claims it exhibits about an order of magnitude deeper storage than other available A/D boards. Capable of continuous acquisition at up to up to 1.5-Gsamples/s, this board can store up to 16-billion samples of uninterrupted analog data.
Designed for high-speed low-jitter operation, the externally-triggerable AD8-1500DMA can also operate with an internal or external clock with any frequency from 10-MHz to 1500-MHz. The combination of speed and record length storage can readily support continuous intelligence gathering, medical imaging, and single-shot testing.
Typical applications include wideband surveillance, radar, sonar, microwave component testing and characterization, and NMR/MRI (nuclear magnetic resonance imaging) development.
Operating System Versatility
AD8-1500DMA boards can be socketed in 64-bit workstations, industrial PCs, and servers. Ultraview recommends Dell Precision 670 workstations running 64-bit Linux, or Sun Microsystems workstations running Sun’s Solaris operating system.
Like Gage’s boards, FPGAs are at the heart of the digital processing section of an AD8-1500DMA. Xilinx XC2VP30 FPGAs can either be programmed with Ultraview’s data acquisition firmware, or loaded with your own custom firmware.
While it's acquiring a long stream of data into its 16-Gbyte on-board memory, an AD8-1500DMA’s 64-bit 66-MHz PCI DMA (direct access memory) engine can concurrently transfer data from on-board memory to the PCI host. It does this at over 300-Mbytes/s, supporting uninterrupted acquisition and analysis of gigabytes of wideband analog data.
There is a small tradeoff for all of this performance, and that is that the board requires the space of two 64-bit PCI slots.
The single-unit price for the AD8-1500DMA-16GB is about $16,000. The lower memory AD8-1500DMA-8GB version is priced at about $12,000.
Click here for a previous eeProductCenter review, and additional information on Ultraview’s product.
Or, search www.eeProductCenter.com for Article ID: 175801157.
Contact The Vendors In This Article
Acqiris, 845-782-6544, www.acqiris.com
Gage Applied Technologies, 800-567-GAGE, www.gage-applied.com
Interactive Circuits and Systems, 613-749-9241, www.ics-ltd.com
Ultraview, 925-253-2960, www.ultraviewcorp.com
ZTEC Instruments, 505-342-0132, www.ztec-inc.com