Logic And Protocol Analyzers Acquire More Muscle

For designers of telecommunications and wireless products, the challenge is to choose an appropriate mix of instruments for analysis and debug, and the move is to logic and protocol analyzers. Fledgling digital system designs are still plagued by problems arising from fast, complex signals, including glitches, noise, and anomalies. These aberrations are analog in nature, although the system itself is digital. So, a high-performance oscilloscope remains the best tool for rooting out the causes of signal aberrations.

But logic analyzers are fast becoming the core tool for digital acquisition, display, and analysis because they offer 2- to 4-ns resolution, adjustable setup/hold times, and adjustable voltage thresholds. Also, they usually provide simple state listing and timing waveform display, plus powerful triggering.

As for protocol analyzers, they're better at software debug due to deeper buffers and the ability to configure triggering and filtering at a high level without knowledge of how the bus signals behave. Protocol analyzers also usually offer powerful statistical analysis capabilities, plus displays at the command, packet, and state levels. But they don't provide a timing waveform display.

Do you want a logic analyzer yet want to pass on becoming an expert? (See "Shopping For A Logic Analyzer," p. 42.) With its Windows Interface, single-screen operation, and straightforward triggering, Agilent Technologies' 1680 and 1690 series logic analyzers minimize the learning curve by providing a single-screen home base. They enable designers to access the instruments' most commonly used features through familiar Windows icons. Advanced features are easily accessible via a pull-down menu from the main menu bar.

Both series of logic analyzers provide 200-MHz state analysis, up to 800-MHz timing analysis, 200-MHz transitional timing, and offline analysis of captured data streams. Sixteen models offer a variety of channel counts and memory depths. Customers can choose from benchtop or PC-hosted form factors that best match their needs.

Agilent has also added a new eye scan mode to its 16760A logic analysis module. In a single image, it lets users examine eye diagrams on hundreds of nodes simultaneously. In the eye scan mode, the in-strument monitors incoming signals for ac-tivity in a time range centered on the clock and over the full voltage range of the signal. The results are displayed similarly to how the eye diagram is displayed on an oscilloscope.

Until recently, engineers were limited to one monitor. They had to continuously scroll up and down to compare data, as well as toggle between application windows to work concurrently with the logic analyzer and its debug tools. But Tektronix has recently introduced two mainframes, the TLA715 and TLA721, that significantly increase display area. These mainframes add multimonitor capability to the TLA700 series logic analyzers, increasing the available viewing area.

In addition, the new mainframes employ the Intel Pentium III processor, which en-hances system performance. Both mainframes accept existing TLA700 series instrument modules, including logic analyzer, digital oscilloscope, and pattern generator versions.

Tektronix also announced its integrated view (iView) package. The integration is based on the transfer of up to 4-GHz oscilloscope waveforms to a logic analyzer display. This is said to be the first time that this level of oscilloscope performance has been paired with a logic analyzer. It's particularly beneficial for designers faced with solving signal-integrity problems on the latest high-speed processors and buses. The iView package includes TLA Application Software, version 4.1, and interconnections for linking TLA600 and TLA700 series logic analyzers with external oscilloscopes in the TDS7000, TDS684C/694C, and TDS3000 series.

Bluetooth Test Sets Are Flourishing: Bluetooth wireless is presenting new challenges to many designers. The combination of leading-edge 2.4-GHz RF and protocol technologies, coupled with the requirement to lower implementation costs to a few dollars, is particularly demanding.

To help fulfill these requirements, Anritsu's MT8850A Bluetooth Test Set addresses the industry's demand for Bluetooth test instrumentation. It conducts measurements in accordance with RF Test Specification V0.09 and uses the Bluetooth protocol stack for full implementation of test-mode signaling. It targets production test of Bluetooth chip sets and modules, and consumer products that use Bluetooth modules. Aside from conducting standard measurements according to the Bluetooth specification, the MT8850A can be configured to run custom test scripts.

A nonintrusive Bluetooth test tool for capturing and displaying Bluetooth piconet data is Merlin from Computer Access Technology Corp. (CATC). One of its key features, its "Air Probe" radio interface, lets users communicate with a local piconet. It uses hardware triggering to capture real-time events and hardware filtering to preserve memory and help pinpoint data of interest.

The software displays all piconet traffic as color-coded packets and includes advanced functionality for filtering and sorting Bluetooth data, searching for specific packet types and/or errors, and many other tools for appraising Bluetooth traffic. As a standalone unit, Merlin is easily configured and controlled by a host portable or desktop PC connected via its USB port.

The Finisar Systems GTX Notebook System is an all-in-one portable, laptop-based analyzer, bit-error-rate tester, error injector, and generator for storage-area networks (see the figure). It's well suited for design and field service applications engineers, supporting Fibre Channel, InfiniBand, and iSCSI protocols. It supports both 2.125- and 1.062-Gbit/s clock rates for Fibre Channel, and 2.50 Gbits/s for InfiniBand. The GTX Notebook captures link data and displays in both Fibre Channel and embedded-protocol formats.

Also available as a two-port GTX Notebook analyzer, it can capture data on both ports of a duplex link. The GTX Notebook System provides up to 2 Gbytes of full-speed capture memory, spanning 4 s on a fully loaded, 2-Gbit/s link, including the 48-bit time-stamp for each frame, repeating ordered set, or error. Real-time precapture filtering can extend capture time to minutes.

Agilent's new General Packet Radio Services (GPRS) lab application is an option for the 8960 Series 10 (E5515C) wireless communication test set. With it, R&D integration engineers working on functional verification of GPRS wireless appliance firmware and hardware can access a flexible, comprehensive, and easy-to-use one-box solution for validating a product's parametric and signaling design requirements.

The Agilent 8960 accommodates the requirements of GPRS. The platform's new E6701A software retains the measurement and call-processing capability of the E1964A GPRS mobile test application, which establishes a vital link between design and manufacturing.

The ability to use the same equipment in R&D and production enables a rapid and smooth transition from one phase in the product lifecycle to the next, as well as improved troubleshooting processes. The test set's protocol-logging capabilities facilitate testing and troubleshooting of new signaling features and data channels so that engineers can extract better information about their design.

Logic And Protocol Analysis Unite: Data Transit's Bus Doctor lets users perform both logic and protocol analysis. Recognizing that a dedicated protocol analyzer has drawbacks, the Bus Doctor overcomes such limitations through ancillary pods that customize the instrument. It thereby acquires a bus-specific personality for each particular bus application, such as ATA, USB, Fibre Channel, IEEE 1394, PCMCIA/CardBus, InfiniBand, and Logic Analysis.

The hardware pods provide the physical connection to the bus and tell the analyzer which bus is under test without any configuration by the user. Software configures the pod hardware each time the analyzer is powered up.

Another unusual feature is a user-definable histogram. This is a summary of where specific events occurred throughout the trace. Users can define their own events of interest, then see them displayed in the histogram.

The Bus Doctor's buffer segmentation lets users divide the buffer into smaller pieces by any binary value from 1 to 256 to provide up to 256 different trace segments. Users can then choose one huge trace or multiple smaller traces.