The price and performance of almost any data acquisition system (DAS) you buy or design today depend on how well the hardware uses the features of the PC. Whether you design or use data acquisition systems, you need to know the latest features and how they affect system architecture, composition and applications.
For example, higher-speed PCs and lower-cost mass storage help process more data at higher rates. But to best use these capabilities, the data acquisition hardware must handle and forward the data at a comparable speed. To satisfy this need, some high-speed data acquisition boards now employ the PCI bus–which is becoming common on almost all high-end PCs–to transfer acquired data.
Math-intensive data processing is often more efficiently performed by digital signal processors (DSPs) than by general-purpose microprocessors. Multimedia and other commercial computation-intensive applications have created a market for DSP devices, making DSPs and DSP plug-in boards exceedingly cost-competitive.
As a result, many data acquisition system designers are contemplating or already are using DSPs. Both methods–incorporating them into the data acquisition circuitry or using separate DSP boards–have their pros and cons.
Another aspect that affects data acquisition implementations is the changing form factor of the PC. The continuing trend of placing more circuitry into each IC is resulting in the widespread availability of powerful, yet affordable, laptop and notebook PCs. Many portable PCs are equipped not only with the conventional parallel port, but also with PCMCIA card slots. Either of these ports can be used to control and communicate with data acquisition system components, but PCMCIA recently has been gaining a great deal of attention.
Today, only a few data acquisition products are PCI-based, although more introductions are on the horizon. But there are many data acquisition systems already using DSPs, and the number of portable systems in service is rising exponentially.
Portability
Lightweight notebook PCs have added a new dimension to data acquisition. It has always been possible to collect data in the field by using dataloggers or stripchart recorders, but effective real-time processing of that data was often limited by cost and performance constraints.
“Dataloggers tended to be slow, with proprietary operating systems that didn’t allow for easy data analysis,” said Ed Pastor, Marketing Manager at Keithley MetraByte. “Stripchart recorders did not support computerized data analysis at all. But with a notebook PC and a PCMCIA data acquisition card, you can now cost-effectively collect and analyze data in the field.”
Laptop or notebook PCs with PCMCIA slots can serve as control and data-analysis platforms for a portable data acquisition system in either one of two configurations. All of the data acquisition electronics may be contained within the PCMCIA card–now usually referred to as just the PC card. Or, the PCMCIA connector and adapter may merely serve as a port interface to the external data acquisition hardware.
PC Card Implementations
PC card-based implementations have two advantages over printer port-connected products: speed and appearance. “Data acquisition speed is enhanced since PCMCIA allows direct access to the computer’s bus in much the same manner as an ISA card,” said Roger Lockhart, Vice President at DATAQ Instruments.
“And the appearance appeal of PCMCIA is almost unbeatable. The idea of a credit card-sized product which, when inserted into a sleek, low-profile slot of a laptop PC, turns the system into a multichannel data acquisition solution is a difficult benefit to ignore,” he continued.
While the space on the PC card limits the number of analog channels (usually 8 to 16) as well as digital I/O and signal conditioning features, their capabilities are more than adequate for many applications. For example, the DAQCard-1200 from National Instruments has the functionality of the company’s Lab-PC+ DAQ Board, which has found many applications since it was introduced about five years ago.
When channel expansion, extra isolation or extensive signal conditioning is required, many companies provide integrated add-on solutions. National Instrument’s SCXI external system connects to the DAQCard-1200, and the Keithley DASCard-1000 capabilities can be extended with the EXP-1600 expansion chassis. Alternatively, channels can be added by plugging another card into a second PCMCIA socket.
IOtech offers channel expansion and signal conditioning via one or several portable chassis that cable to a PC card in the notebook PC. The chassis may contain a range of cards to accommodate various signals, such as thermocouples, strain gages, RTDs, high voltage and current. These expansion options come with an optional battery supply so that they do not drain the battery power source of the host notebook PC.
The relatively slow (80 kB/s to 150 kB/s transfer rates) parallel-port standard implemented in older PCs has been supplemented by the faster extended parallel-port (EPP) standard. EPP is becoming widely implemented on notebook PCs. However, transferring data via a PCMCIA slot provides even greater speed advantages.
“Connecting an EPP-based data acquisition module directly to a notebook PC can provide up to 800 kB/s,” explained Allen Tracht, Principal Engineer at IOtech. “But going through a PC card interface increases your sampling rate up to 1 MS/s. IOtech’s new WaveBook/512, a portable, high-speed multichannel digitizer, can be used with the WBK20, a PC card interface, to achieve the 1-MS/s throughput.”
Potential PCMCIA Shortcomings
Not everyone endorses PCMCIA-based solutions. Concerns focus on physical issues, understanding of PCMCIA concepts and specification stability.
Mechanical Issues
: The PCMCIA’s small form factor does not automatically translate into reduced field wiring. A sturdy screw terminal accessory is still necessary to interface signals to any data acquisition system. Also, terminating a multiconductor cable into a thin (5 mm for a Type II and 10.5 mm for a Type III) card so that it can withstand severe field service conditions is not a trivial endeavor.
Lack of Understanding: Many users do not rely on the features PCMCIA offers. “During a recent survey, I discovered that the PCMCIA capability is not fully understood by developers or users,” said Chad Stalker III, Product Marketing Manager at Data Translation. “Many people only use one type of card in their system at a time. They also needlessly reboot whenever they switch them out; for example, when going from the Ethernet card to the fax/modem card. This simple type of misuse is still common.”
Real operational conflicts may also exist due to design anomalies. After all, many different elements must be understood by the PCMCIA product developer, including the PCMCIA standard, card and socket services; card controller chip technology; the specific PCMCIA card driver and, of course, the application.
Specification Content and Stability:
PCMCIA documentation efforts began in 1989; and while the specifications completely define some requirements, others are somewhat fluid or are still being defined to reflect advancements. Some specification shortcomings that should be taken into consideration were outlined by Rick Lagrand, Sales Manager at Access I/O:
The computer’s bus clock is not supported by PCMCIA.
The MEMCS16 signal is not supported, so I/O cards are restricted to only 8-bit or 16-bit memory ranges but not both.
DMA channels 0, 2 and 6 are not supported.
IRQ 6, 12, 14 and 15 are not supported.
But many of these and other shortcomings will be overcome through closer cooperation between PC, PC card and application-oriented designers. Specifications will be updated and new product developments will continue, such as the new faster CARDBUS, which will be implemented in future portable PCs.
“When CARDBUS arrives, all of the current limitations (except limited space for circuitry on the card) will be solved,” said Romer Johnson, Design Engineer at Intelligent Instrumentation. “Since CARDBUS is just an extension of the PCI bus, the benefits of PCI will still be available. Bus mastering, auto configuring (plug and play), and greater bus bandwidth will all be accessible to the PC card. This will lead to some extremely high-performance and powerful portable systems.”
A Multitude of DSP Benefits
Many data acquisition system designers and application engineers once believed that DSPs were useful only for high data rate applications. But now it is widely recognized that low-cost DSPs can even benefit many low-speed applications. They not only perform the same functions that more expensive glue logic or ASICs often perform; but because they are programmable, they foster flexibility and forestall obsolescence.
A dedicated DSP can give its undivided attention to an application–a situation which is usually not true for the host PC’s microprocessor–and guarantee real-time control. The DSP can also off-load the host, and freeing its processor to perform other operations more efficiently. And finally, when speed is essential, it is often the only practical solution.
These applications portray some of the aspects that should be considered when weighing the pros and cons of employing DSPs.
Enhancing Functionality With DSPs
DATAQ Instruments is a company that has used DSPs in its A/D products since 1992. “We applied the DSP as a replacement for the random logic required for high-performance data acquisition,” said Mr. Lockhart.
“As a result, our products offered 256-position scan lists with programmable gain, unipolar/bipolar and single-ended/differential inputs/channel,” he continued. Also supported were analog pre- and post-triggering and the capability to sample different channels at different rates. This mix of features was provided on a card containing only 19 ICs.
In addition to the cost savings, DATAQ includes signal averaging for noise reduction, peak and valley detection for AC measurements, and auto-zero functions for enhanced TC-based temperature measurements. All these features are software upgrades, yielding an inexpensive and convenient growth path.
Another example that illustrates the range of enhanced DSP functionalities is the IOtech WaveBook/512. With its DSP-based design, this notebook add-on provides real-time digital calibration on a per-channel basis, eliminating manual adjustments and allowing expansion and installation of options without calibration. DSP also enables the WaveBook to have single and multichannel triggering with programmable level and slope, according to Mr. Tracht.
Dependable Control and Real-Time Operations
DSPs may seem an overkill for certain ‘slow’ control applications, but this is not the case if the control process is critical, said Robert Gaurie, Engineer at Sheldon Instruments. “If the host CPU is tending to the mouse or is going into a screen-saver mode, the CPU will temporarily abandon the control process, possibly leaving the controlled system in an undesirable state.”
Vibration control is a case in point. An application such as controlling a four-pole shaker in an automotive test setup demands a dedicated processor, commented Richard House, Data Acquisition Marketing Manager at National Instruments. “These applications need fast computations and they don’t want anything to interrupt them.”
Not only can DSPs be used for data acquisition applications requiring real-time control, but also for those that benefit from real-time data processing. “Whenever processing beyond averaging, scaling or other simple calculations is required, a DSP-based system should be considered,” said Jeff Brower, President of Signalogic.
“DSP proves indispensable in general areas such as real-time filtering, frequency zoom, sampling rate conversion, fuzzy logic implementation, spectral or wavelet analysis, and stimulus and response measurement. Traditional acquisition functions where a DSP may be beneficial are trigger criteria and history.
“For example, a DSP with a large amount of external SRAM can implement pretriggering independent of the host. When an event of interest occurs, the host can ask for large amounts of data preceding the event. Eliminating the need for host intervention means that very complex trigger conditions can be imposed and sampling can still occur continuously at very high rates,” Mr. Brower concluded.
Off-Loading the Host
A DSP may be used to off-load processing tasks typically performed by your PC’s CPU. When mathematical processes are involved, the DSP will do it even more efficiently.
“In applications for which DSPs are optimum, you can get as much or more performance from a DSP than from a Pentium processor, and all computational power is dedicated to your data acquisition and processing task,” commented Ron Walk, Strategic Marketing Manager at Intelligent Instrumentation. “Actually, a DSP can do for data processing what a graphic accelerator does for graphics.”
Having a DSP coprocessor combined with a data acquisition board can offer a lot of value off-loading the host processor and obtaining the desired system speed and performance, concurred Bob Leonard, Product Manager, Data Acquisition at DATEL. “A DSP on board can off-load the host and allow synchronous operation of all I/O aspects while providing powerful number-crunching from engineering scaling through FFTs. For example, DATEL’s PC-430 boards offer a TI320C30 (40-MHz clock) DSP coprocessor and on-board dual port RAM (512k), also obviating the need for external RAM memory.”
Improved Throughput
DSPs should always be considered when high throughput is a paramount requirement. “The applications most likely to benefit from DSPs are those requiring calculation-intensive signal processing, because the architecture of the DSP has been streamlined for this specific class of functions,” said Greg Pillar, Software Engineer at Sonix.
“The type of calculations usually takes a sum-of-products form,” Mr. Pillar continued. “For instance, the use of a DSP may allow real-time filtering of the data, where a filtering calculation performed by the CPU would have reduced throughput to an unacceptable level.”
Not only do some DSPs perform certain operations faster than the PC’s microprocessor, but integrating the DSP with other data acquisition functions also provides benefits. Most of the computational and control efforts are being performed by the DSP without requiring any host resources. Consequently, host bus traffic is greatly reduced, further boosting the PC’s net transaction speed.
On-Board DSP vs Separate DSP Board
DSPs may be co-located with the data acquisition components on a single board or may be situated on a separate board. Pros and cons exist for either implementation.
When space is limited, a single data acquisition board with DSP is advantageous since it occupies only one slot in the host computer. Also, a single-board solution is always less expensive than a separate DSP board.
“Whenever the DSP is post-processing data, the trade-off issue between an on-board DSP or a separate DSP board is primarily cost vs flexibility,” said Mr. Walk. “By using a separate DSP board for data processing, you can select virtually any data acquisition functionality.”
A separate DSP board has the advantage of modularity. “DSP boards can be configured with a variety of acquisition boards for different requirements, concurred Tim Lofink, Product Marketing Engineer at Loral Test and Information Systems. “Multiple DSP boards may also provide an easy hardware solution to problems requiring more performance than is available on a single board.”
Reasons for choosing a separate DSP board implementation include speed; architectural limitations, such as insufficient memory on the single board; and space. “Most of the higher-speed A/D boards are very limited in board; real estate so there isn’t enough room for a DSP,” said Mr. Pillar. “We developed a separate DSP board optimized for data throughput, the SDC5600, which includes a proprietary high-speed (25 MB/s) link to our A/D boards.
“This approach also provides flexibility. For instance, multiple SDC5600s can be connected to multiple A/D boards on the same high-speed link. This allows sharing of one DSP board between multiple A/D boards or using multiple DSP boards for each A/D board. This flexibility is not available on A/D boards with built-in DSPs,” Mr. Pillar concluded.
But there is a negative aspect to consider when using separate DSP boards: a substantial amount of data is continually being transferred between the data acquisition and the DSP boards. If this traffic takes place over the ISA computer bus, it can slow down host-computer operations. A separate mezzanine bus alleviates this problem, and computers equipped with the PCI bus can easily handle the added traffic.
DSP Board, DSP or No DSP?
For many control and real-time applications, the DSP is essential. Versatility is another plus.
“The flexibility allows cards to have multiple functions,” said James Bridges, President of Communication Automation & Control. “The card could be doing speech recognition on the incoming audio signal, encrypting the speech and providing audio feedback on the output all at the same time. If it still has processing power left, the host CPU can download some of its own chores to the DSP and let it act as a special coprocessor.”
For nonreal time or noncontrol applications, a separate DSP card may help process very large blocks of data. “If the DSP is properly coded and the host CPU is significantly slower, the shorter DSP post-processing time enhances productivity,” said Mr. Gaurie. “However, with the advent of better floating point units in standard processors, the gap is narrowing.”
The processing power and software development tools associated with general-purpose processors, such as Power PC or Pentiums, are increasing at such a rate that today they have the performance of general-purpose DSPs of only a few years ago,” concurred Mr. House. “However, while the speed advantage may be diminishing, DSPs will always be needed when applications call for a dedicated processor for a specific task.”
Data Acquisition Products
PCMCIA DSP Board Provides Dual
Professional Audio Channels
The DARTdsp PCMCIA Interface Card serves as a floating-point accelerator and professional audio I/O subsystem for portable PCs. Based on 33-MFLOPS DSP3210s, it provides CD-quality audio I/O. The sampling rate (8 to 48 kHz), input gain (0 to 22.5 dB) and output attenuation (0 to -46.5 dB) are programmable via DSP or the host. The CS4216 16-bit codec’s sigma-delta A/D input features 64X oversampling, linear phase and digital anti-aliasing filters. The D/A output portion features interpolation filters enabling automatic sampling-rate tracking. $995. Communication Automation & Control, Inc., (610) 776-6669.
PCMCIA 16-Bit A/D Card Has
Software-Selectable Ranges
The PCM-DAS16/16 is a 100-kHz A/D card in 16-channel single-ended or 8-channel differential versions. Software-selectable gains allow input ranges of ± 10 V, ± 5 V, ± 2.5 V and ± 1.25 V. A 512-word FIFO buffer ensures transfer of large blocks of data without loss of samples. On-board 16-bit counters supply A/D pacing, event counting or frequency measurements. Drivers and support for all programming languages for Windows or DOS are included. $549. ComputerBoards, Inc., (508) 261-1123.
Data-Acquisition System
Optimized for Thermocouples
The DI-221 TC is a parallel port-connected 12-bit, 16-channel portable data acquisition system for performing thermocouple-based temperature measurements and acquiring other analog signals. Up to 16 grounded thermocouples or other analog inputs can be connected in any combination via the built-in signal I/O panel. A sensor attached to the signal-termination receptacles on the PCB provides cold-junction compensation. $1,695. DATAQ Instruments, Inc., (800) 553-9006.
EISA A/D Boards Stream
Data to Memory at 10 MHz
The PC-415 family of data acquisition boards digitizes high-speed analog inputs, forwards the data into FIFO memory and transfers it to the host under program control. Up to 16 channels can be combined with 12- to 16-bit resolution and sample rates to 10 MHz. Two/four/eight-channel simultaneous sampling options eliminate phase skew on multiple channels. Software support includes a menu-driven setup and a configuration library. From $1,925. DATEL, Inc.,(508) 339-3000.
Easy-to
–
Use System
Suited for Labs
LAB-ACQ measures temperature, pressure, strain or other transducer-converted data without need for external transmitters or signal conditioners. It scales and linearizes the data and stores readings to disk in an ASCII file. The system plugs into the parallel printer port of a PC and has six channels (expandable to 48). The company’s INSTA-TREND is available for DOS and Windows. $1,995. Dianachart Inc., (201) 625-2299.
Board Set Performs A/D and
Transfers Data to 90 MB/s
CompuScope 6012/PCI is a two-board data acquisition system. Signal conditioning and A/D conversion takes place on the CSx012 ISA bus analog board and data storage and PCI bus interfacing on the 6012PCI board. CompuScope 6012/PCI samples two channels simultaneously with 12-bit resolution at up to 30 MS/s or one channel at 60 MS/s. Data is stored in the 6012PCI on-board memory or read into the PC’s memory. The system operates in memory or a real-time mode and features flexible triggering. $8,995. Gage Applied Sciences, Inc., (800) 567-GAGE.
Data Acquisition Software
Saves 8 Million Data Points
The new version of Snap-Master™ saves up to 8 million pretriggered data points prior to a failure or other major event. Applications include capturing an intermittent event or a malfunction during long-term durability and reliability testing. This feature is accomplished by improved memory management within Version 3.0 of Snap-Master for Windows, a data acquisition display, analysis, storage and playback program. Real-time plotting performance is up to 110,000 S/s. $495 to $995. HEM Data Corp., (800) 436-4330.
PCMCIA System Requires
Only 1 W of Power
The I/Ocard Portable Data Acquisition System consists of a PC card that connects to a PCMCIA Type II slot and a termination pad. It features eight differential analog inputs, 12-bit resolution, 30-kHz throughput and external triggering. Model PCI-460P-1 provides software-selectable gains of 1, 10, 100 and 1,000 and the PCI-460P-2 has gains of 1, 2, 4 and 8. Cold-junction compensation, a voltage-reference output and four digital I/Os are provided. I/Ocard is supported by Visual DesignerTM Windows-based application-generator software. $595. Intelligent Instrumentation, Inc., (800) 685-9911.
Add-On for Notebook/Desktop PC
Provides 1-MHz Sampling
The WaveBook/512 is a DSP-based 12-bit-resolution, 1-MS/s portable data acquisition add-on for notebook and desktop PCs. It is an eight-channel instrument expandable to 72 analog channels via optional expansion modules. WaveBook/512 also accommodates eight digital inputs, readable up to 1 MB/s. The DSP-based design helps define random scan sequences and associated gains across all potential channels. PC connection is via the enhanced parallel port or an optional PCMCIA card interface. $2,495. IOtech, Inc., (216) 439-4091.
Cards Provide Analog/Digital
I/O in PCMCIA Format
The DASCard-1000 Series of high-speed analog/digital I/O cards features 16 single-ended or eight differential inputs at up to 140 kS/s in a Type II PCMCIA format. Inputs are software-configurable for single-ended/differential and bipolar/unipolar ranges. Gap-free acquisition under Windows or DOS is facilitated with an on-board FIFO memory. The cards are shipped with an 18″ cable terminated in a standard 37-pin D connector which may be plugged into accessories such as screw-terminal connectors or signal-conditioning units. $599. Keithley MetraByte, (800) 348-0033.
Visual Telemetry Software
Includes Ethernet Accelerator
VTS 200 Visual Telemetry is a Windows-based software package to support acquisition, processing, archiving, display and distribution of data in a network-based operating environment. It enables the network to serve as the real-time data bus, eliminating the typical PC bus-speed limitations. An Ethernet accelerator distributes data from the server to multiple clients. From $6,000. Loral Test and Information Systems, (619) 674-5100.
PCMCIA DAQ Interface
Product Line Extended
The DAQCard-1200TM, one of four new DAQCard products, is a multifunction PCMCIA data acquisition interface featuring analog, digital and timing I/O. Possessing capabilities identical to the company’s Lab-PC+ plug-in board, the DAQCard-1200 features a 12-bit ADC with eight single-ended or four differential analog input channels; a sampling rate of 100 kS/s; and gains of 1, 2, 5, 10, 20, 50 and 100. It has two 12-bit analog output channels, three user-available counter/timers and 24 lines of digital I/O. $695. National Instruments, (512) 794-0100.
Temperature/Voltage Interface
Unit Features Speed, Isolation
The OMB-MULTISCAN-1200 Data Acquisition Interface features channel-to-channel isolation for temperature and voltage measurements. The high-speed design facilitates scanning of temperature and voltage inputs at a rate of 147 channels/s. Up to 744 channels are available through an expansion chassis. On-board memory of 256 kB is standard and storage may be expanded up to 8 MB through optional modules. Windows-based software for datalogging and graphing is included. Basic 24-channel system: $2,490. OMEGA Engineering, (203) 359-1660.
System Features
Digital and Analog Outputs
The Model 100 Data Acquisition System features a 12-bit, 100-kHz analog-to-digital converter along with an eight-channel single-ended or four-channel differential input. Single/differential input selection and gain settings are software programmable. Four channels of 8-bit analog outputs and three counters/timers (16-bit) are also provided. $279. Prairie Digital, Inc., (608) 643-8599.
High-Resolution Multi I/O Card
Interfaces With DSP Card
The SI-DSP1600 is a high-resolution, multifunction data acquisition and control card. Four analog inputs are simultaneously sampled at 16 bits with sampling rates ranging from 39 Hz to 55.8 kHz. The ADCs employ a sigma-delta architecture which virtually eliminates the need for on-board anti-alias filters. Two analog outputs can update at rates up to 55.8 kHz with 16-bit resolution. Eight general-purpose digital I/O lines are programmable as inputs or outputs. $640 to $785. Sheldon Instruments, (800) 376-7861.
Waveform Digitizer Features
DC to 500-MHz Bandwidth
The DA500A Waveform Capturing System has an analog bandwidth of DC to 500 MHz and employs a 500-MHz digitizer with 8-bit resolution. On-board memory is 256 kB, expandable to 8 MB and 32 MB. The DA500A is PC AT-compatible (ISA bus) and incorporates the Signatec Auxiliary Bus (SAB), a high-speed bus that allows data transfers up to 200 MB/s. Two DA500A boards may be connected in a master/slave configuration. $6,700. Signatec, Inc. (909) 734-3001.
Performance Improved
Through DSP Board
The SDC-5600 DSP Board increases the performance of acquisition and analysis systems. By passing data directly from the A/D board to the DSP, transaction overhead is reduced. Key features include dual memory banks of zero wait-state SRAM, data throughput accelerator circuitry for on-the-fly numeric format conversion and transfer rates of 32 MB/s from Sonix A/D boards via a mezzanine bus and 5 MB/s via an ISA bus. Sonix, (703) 440-0222.
DSP/PCI Card Suited For
Math-Intensive Applications
The PCI/C80 Card implements a 32-bit PCI interface with TI’s 2 GOPS TMS320C80, a combination that permits data transfers between DSP and a host at rates up to 132 MB/s. To maximize storage and minimize delays, the board has up to 32 MB of fast page-mode DRAM and 8 MB of zero wait-state SDRAM. The new card is suited for high-speed processing applications, including radar scan conversion, medical imaging, high-speed inspection or image enhancements. $8,295 for version with SDRAM. Spectrum Signal Processing Inc., (604) 421-5422.
Software Provides
File-Handling Advancements
A new version of NetDAQTM Logger for WindowsR software includes several enhancements, such as autofile rollover and deadbanding. Autofile rollover manages files when acquiring data for long periods. New files are automatically created when a file reaches a predetermined size or at specified time intervals. Deadbanding allows users to preset inside or outside bandwidth tolerances on collected data to reduce unwanted massive extraneous data collection. $1,295. Fluke Corp., (800) 44-FLUKE.
Analog Multiplexer
Operates at 1 MHz
The UEI-MUX/01 is a high-speed analog multiplexer with 16 single-ended or eight differential analog inputs and four analog outputs. Up to 256 UEI-MUX/01 boards can be daisy-chained, allowing 4,096 single-ended or 2,048 differential inputs operating at a 1-MHz throughput. Software is provided for DOS or Windows environments, and third-party software support includes LabView, LabWindows/CVI, Snap-Master and Labtech Notebook. $395. United Electronic Industries, (800) 829-4632.
Portable Data Acquisition
Compatible With PCMCIA
The PC Card-EZ™ Series for portable data acquisition is compatible with PCMCIA PC Card Standard Release 2.1. The first model available in the series, the DT7101, acquires eight single-ended/four differential channels of analog input at 12-bit resolution with 11.3 bits accuracy to 100,000 S/s. It provides four lines of digital I/O, requires little power (30 mA operating, 10 mA standby) and runs in a Type II slot. Microsoft Windows’95 Plug ‘N Play with Card Manager™ software accompanies the series. $495. Data Translation, Inc., (800) 525-8528.
Software Interfaces With
Off-the-Shelf DSP Hardware
The DSPower-HWLib Windows DLL software offers a PC-based instrumentation interface to off-the-shelf DSP/acquisition hardware for user-defined programs. Example spectrum analyzer, digital oscilloscope, stripchart and digital tape recorder demo programs and C++ source code are provided. Low-level functions include DSP/acquisition board control, block memory transfer and DSP executable file downloads. High-level functions include waveform record/playback, signal synthesis, stimulus and response measurements and DSP/math functions. HWLib DLL allows direct access to DSP devices. $495. Signalogic, Inc., (800) DSPower.
Copyright 1995 Nelson Publishing Inc.
November 1995
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