Test and Measurement

-- EDN, 12/9/1999

Four-channel CompactPCI digitizer takes 1G sample/sec/channel. The 6U-sized, $15,980 DC270 with option M2M houses four 1G-sample/sec ADCs, each with a memory of 2M samples and an analog bandwidth of 250 MHz. A unit with a memory of 128k samples/channel costs $11,990. The DC265, which samples half as fast and offers 150-MHz analog bandwidth, costs $9990. A $2490 option increases the memory depth to 1M sample/channel. The modules offer a sequential-trigger mode that rearms in less than 500 nsec and a proprietary autosynchronous bus. The bus, which travels from the front of one module to the next on flexible jumpers, synchronizes acquisitions within 100 psec and requires no user configuration. Acqiris USA, 1-877-227-4747, www.acqiris.com.

Audio-filter instrument is analog outside but digital within. Frequency Devices' ASC50 is a $3900 benchtop unit measuring 5.25 in. highx8.75 in. widex13 in. deep. With a few presses of the ASC50's front-panel keys and without programming, you can call up thousands of DSP- and analog-filter designs in the 0.1- to 30-kHz frequency band. The unit synthesizes lowpass, highpass, bandpass, and band-reject (notch) filters with Butterworth, Chebychev, elliptic, and FIR characteristics. Lowpass and highpass filters can have four to 10 poles. Three- and four-pole bandpass and notch filters can have Qs of 2, 5, 10, or 20. FIR filters can follow FIR-40, -60, or -80 functions. The input is ±10V single-ended or differential into 1 M? in parallel with 47 pF. The unit provides a ±5V programmable dc offset, prefilter gain of 0 to 36 dB in 6-dB steps, and postfilter gain of -48 to +42 dB in 6-dB steps. The output is ±10V single ended from a 1? source. Frequency Devices, 1-978-374-0761, www.freqdev.com.

Measurement-and-automation applications call Matlab scripts. Version 5.1 of National Instruments' flagship Labview graphical environment for developing measurement-and-automation applications now allows programs to call Matlab (www.mathworks.com) M scripts. Other improvements in the latest version of the software include a new application architecture, which decreases memory usage and increases execution speed. Applications are now dynamic-link libraries. New tools enable users to publish virtual-instrument panels to Web pages in seconds without programming. A 3-D graph control improves the software's ability to let users visualize acquired data. The software is available for several Windows and Unix OSs as well as the Power Macintosh. US prices start at $995. Upgrades from earlier versions cost $295 to $395. National Instruments, 1-800-258-7022, www.natinst.com.

PC-hosted logic analyzer slashes price, learning curve. The LogicWave, a $3200 logic analyzer from Agilent Technologies, uses a PC's large color screen for a display, hard drive for storage, and keyboard and pointing device for control. LogicWave boasts 34 channels, each of which has a memory depth of 128k samples. The instrument, which can perform 250-MHz timing analysis and 100-MHz state analysis, costs about half as much as more familiar HP logic analyzers of similar performance. A key to the LogicWave's ease of use is the design of the screen displays, which provide enough information to avoid most of the switching among windows that earlier units require. Agilent Technologies, 1-800-452-4844, ext 6677, www.agilent-tech.com.

Matchbook-sized Web server enables Internet-based measurement and control. The $95 (10,000) Bfoot-10501 Web-server module has a footprint less than half that of a credit card and conforms to the IEEE 1451 "smart-sensor" standard and the newly ratified IEEE 1451.1. The module uses the VxWorks real-time operating system and Tornado development tools from Wind River Systems (www.windriver.com). Standard tools for editing HTML enable the development of simple Web pages for displaying data that Bfoot supplies. Java scripts let you create more complex pages. Moreover, several standard applications, such as Microsoft's (www.microsoft.com) Excel and Word, directly support importing, formatting, and displaying Web data without separate Web-authoring tools. Technology that you can order in Bfoot (Option 077) allows synchronization of Ethernet-connected units to within 200 nsec. A version of Bfoot for developing applications costs $615. Hewlett-Packard Co, 1-800-452-4844, ext 6711, www.hpie.com.

DSO package shows three views of jitter. The $3495 JitterPro software package for LeCroy's LC584 and LC684 DSOs gives you three ways to view jitter on high-speed logic signals. You can view the phenomenon as jitter versus time, as a histogram of timing-parameter measurements, and as a frequency spectrum of the jitter components. The package works equally well on jitter in datacomm and telecomm data streams and on high-speed-clock jitter. Moreover, the package measures and characterizes clock-to-data jitter-for example, in setup-and-hold times. The package takes advantage of LeCroy scopes' deep memory (as many as 16M samples) to make rapid and statistically valid measurements. According to the company, the package enables its scopes to make jitter measurements 100 times as fast as can competitive scopes. The package provides a noise floor as low as 2 psec and permits measurements on clock skew at widely distributed points. LeCroy Corp, 1-800-453-2769, www.lecroy.com.

Desktop PCs communicate with CompactPCI modules at 100 Mbytes/sec. For those frustrated with CompactPCI/PXI systems' frequent need for two computers, National Instruments' third-generation Multisystem eXtension Interface (MXI) bus offers relief. MXI-3 transfers data between a host desktop PC and a CompactPCI/PXI cage at almost 100 Mbytes/sec-10 times the speed of the first-generation MXI. Moreover, the desktop PC need not be close to the CompactPCI/PXI cage. Thanks to fiber-optic technology (required only at moderate to long distances), you can separate the PC and the cage by as much as 656 ft without the need for repeaters. With MXI-3, you can also configure Compact-PCI/PXI systems that require more modules than can fit into a single cage. Such systems now need only one computer, which can be an embedded unit in the first cage or a separate desktop PC. MXI-3 interface kits comprise two cards connected by either a copper or a fiber-optic cable. You need one kit for each pair of units you interconnect. In each kit, the primary card is either a desktop-PCI card or a CompactPCI/PXI module. The secondary card is always for CompactPCI/PXI. Kit prices begin at $1495. National Instruments, 1-800-258-7022, www.natinst.com.

Four-channel, 10G-sample/sec DSO has 3-GHz bandwidth. The TDS 694C pushes the -3-dB bandwidth to 3 GHz and the sampling rate to 10G samples/sec on four channels simultaneously. Because of the TDS 600 series' fast-in/slow-out technology, however, memory depth is 120k samples/channel. Tektonix designed the new scope for cross-triggered operation, simplifying the job of tracking down such problems as metastability and setup-and-hold violations in very fast digital systems. The company is also introducing the 1.5-GHz-bandwidth P6248 low-input-capacitance differential active probe for probing differential signals, such as Rambus clocks and low-voltage differential-signaling logic lines. The TDS 694C costs $37,995. Tektronix Inc, 1-800-426-2200, www.tektronix.com.

Scope responds to voice commands. Agilent's Infiniium digital scopes have an option ($495 when ordered with a new scope; retrofit price for older units depends on µP and memory) that allows the scope to recognize and respond to spoken English-language commands. The speech-recognition algorithms, which come from Lernout and Hauspie (L&H, www.lhs.com), are speaker- and gender-independent and don't require that you train the scope. You speak words or complete-sentence commands. The recognition engine compares the words it recognizes with the grammar stored in its memory. If the recognized words match the stored grammar, or if the engine "thinks" it detects a match, a subroutine uses semantic parsing to interpret the sentence. The subroutine reduces the sentence to tokens, which pass to the scope application via the COM interface. The scope provides visual confirmation by displaying the text of your utterance on the screen. Processing takes approximately 0.5 sec. Agilent Technologies, 1-800-452-4844, ext 6677, www.agilent-tech.com.

Time-interval analyzer makes 2 million measurements/sec. Guide Technology's Femto-2000 system closes the gap between theory and reality. The unit can measure the timing of all pulses in a sequence at frequencies as high as 2 MHz. The instrument also makes statistically valid 1-psec-resolution measurements on pulse trains having frequencies as high as 800 MHz. Moreover, the unit counts every pulse in an 800-MHz pulse train. You can purchase the Femto-2000 with one to four TIAs (two to eight channels). Prices range from $70,000 to $130,000. Input configurations work with differential signals from logic families such as low-voltage differential-signaling and ECL, as well as with single-ended signals. Guide Technology, 1-408-733-6555, www.jitter.com.