Electronic Design

LabVIEW's 20th Anniversary Edition Emphasizes Communications Test

National Instruments celebrates 20 years of continuous improvement in its flagship LabVIEW graphical programming software.

After two decades, LabView still ranks among the most well-known, influential, and widely used engineering software. First announced by National Instruments in the April 17, 1986 issue of Electronic Design (Fig. 1), the company now unveils LabVIEW's 20th anniversary edition, which comes with some features geared for the communications demands of the 21st century .

LabVIEW 8.20 is a significantly updated and expanded version of Version 8. With this edition, Lab-VIEW becomes an even better graphical systems-design platform for test, control, or embedded development. Its key feature is a new extension that addresses communications design, simulation, and test tools specifically for wireless and telecom design and test engineers.

Version 8.20's Modulation Toolkit is a software-defined bag of tricks that enables users to build, simulate, design, and test all manner of communications systems. It includes orthogonal frequency-division multiplexing (OFDM), which is being used in most newer wireless systems such as 802.11a/g, 802.11n, WiMAX, and the forthcoming 4G cell-phone standards.

During simulation, designers can evaluate parameter changes and test their design decisions. Later, they can use that code with external test instrumentation to perform signal measurements at bit-error-rate (BER) tests. The Modulation Toolkit also works with NI's family of RF generators and receivers for implementing a variety of test instruments up to 2.7 GHz (Fig. 2).

"High-bandwidth buses, such as PCI Express, are giving virtual instrumentation and desktop PCs the power to process enormous amounts of complex IF and RF data in communications applications," says James Truchard, NI's president, CEO, and cofounder.

"With LabVIEW 8.20," he continues, "engineers can intuitively develop design models and measurement applications through a graphical programming notation that naturally represents the data flow of communications systems."

The Modulation Toolkit can handle bit generation (PRBS, Galois PN, Fibonacci PN, etc.), channel coding (Reed-Solomon, Golay, Hamming, convolutional, BCH), interleavers (block and convolutional), and just about any form of analog or digital modulation. Also, users can conduct all sorts of modulation analysis, including rho, dc offset, phase error, quadrature skew, IQ gain imbalance, BER, frequency deviation, burst timing, modulation error ratio, and error vector magnitude (EVM).

Furthermore, they can add noise (AWGN or phase) and impairments such as dc offset, fading, quadrature offset, IQ gain imbalance, and frequency offset to the simulated channel to evaluate performance. Then, they can use any one of a number of display formats, such as trellis diagrams, constellation plots, and 2D/3D eye diagram s.

LabVIEW 8.20's MathScript math-oriented textual programming language generally is compatible with the m-file scripts created with the MathWorks' popular Matlab software. MathScript also is syntax-compatible with technical computing software like COMSOL Script. It lets designers use existing Matlab m-file scripts or generate new scripts.

This way, they can mix and match graphical and text-based code for generating stimulus signals of performing measurement on communications signals. Also, users can instrument their algorithms— that is, they can run their m-file scripts with LabVIEW to access instrument control and data acquisition, file and database access, or user-interface development.

Meanwhile, the FPGA Module helps designers define custom I/O without any knowledge of hardware design or VHDL. The FPGA Wizard automates the development FPGA code for building custom, user-defined measurement devices. Users then can implement FPGA-based measurement devices on plug-in boards in a PC for fast, low-cost prototyping or in an NI PXI module for formal production tests.

The FPGA Wizard's intermediate-frequency reconfigurable I/O (IF-RIO) includes two IF digitizers, two IF generators, and an FPGA that's programmed via LabVIEW on a single PCI board. By using IF-RIO, designers can prototype communications systems and then run them in real time on a PC. FPGA Module users can incorporate third-party IP from companies like Celoxica, ImpulseC, and Xilinx.

Another useful new feature is its object-oriented programming (OOP). More and more test applications are being written with OOP. With this ability, designers can create classes and objects, as well as encapsulate data, methods, and all of the usual OOP functions.

OOP development increases productivity by supporting the development of maintainable code, which can be adapted more easily as new test applications arise. It also becomes simpler for users to extend their test applications by minimizing changes to test frameworks while incorporating new test modules. This really benefits large, advanced test systems.

Two other capabilities further boost its usefulness while improving users' productivity. First, with the Instrument Driver Export Wizard, designers can repackage LabVIEW instrument drivers—now numbering more than 5000—and call them from other programming languages as a dynamic link library (DLL). Users then can develop one driver in LabVIEW and support the application using legacy text-based programming languages.

Second, a high-speed data storage schema called technical data management (TDM) documents and stores test results. Based on an open XML schema, TDM lets users embed test data descriptions with their test data files. Designers now can more easily query, search, and find specific test results based on dates, operation, results, or custom properties for post-analysis and reporting.

National Instruments Inc.

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