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Test-and-Measurement Software Puts Real Hardware In the Loop

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AWR Announces TestWave Simulation and Test Integration Software EDA Solution Provides Test and Measurement Equipment Integration Within AWR Design Environment San Jose, Calif.--Applied Wave Research (AWR), a leading provider of high-frequency electronic design automation (EDA) tools, announced TestWave software, integrating test-and-measurement instruments into the AWR design environment. In conjunction with AWR's Microwave Office and Visual System Simulator (VSS) simulation solutions, the TestWave product provides wireless system and radio frequency (RF)/microwave circuit designers a complete integration of the design process, combining schematic simulation, test-signal generation, and test-and-measurement verification. "The TestWave module was designed to provide our customers with an improved product-development process by closing the verification loop with test-and-measurement equipment," said Ted Miracco, executive vice president, AWR. "TestWave software provides a bidirectional interface; simulated signals can be exported from VSS to drive real hardware, and laboratory measurement data may be imported into the simulation. The TestWave solution provides a flexible capability to place 'hardware-in-the-loop.'" By starting with the simulation of digital-communication formats, such as 802.11a, global system for mobile communication (GSM), or wideband code division multiple access (W-CDMA), system components can be simulated and exported from VSS software to a signal generator, which drives the device-under-test (DUT). The measured data from this DUT hardware can be imported back into VSS software and compared with simulation results of the hardware's model. The design can be refined quickly and thoroughly from this direct comparison. Beginning with hardware, vector signal analyzer measurements of real-world data can be imported into the VSS software and used to drive simulation models, with data generated from actual test equipment. Designers can see the effects of the test data on their evolving designs before investing in hardware prototypes. S-parameter data from a network-analyzer measurement can be integrated into a Microwave Office simulation as a behavioral block using the TestWave product. One simulation could use an S-parameter data set as both a circuit and system block, and the same simulation could also use imported IQ waveforms as a stimulus in the VSS software. The TestWave product also enables spectrum-analyzer and oscilloscope measurements to be imported into the simulation environment. TestWave software integrates Microwave Office and VSS software with a wide variety of popular test equipment from manufacturers such as Anritsu Wiltron, Rohde & Schwarz, Marconi Instruments, Fluke/Philips, Tektronix, Boonton, LeCroy, Yokogawa, IFR, Wandel & Goltermann, Advantest, Hewlett Packard, and Agilent Technologies. Equipment types supported by the TestWave product include network analyzers, spectrum analyzers, modulation analyzers, and oscilloscopes. The TestWave solution supports a variety of connectivity methods between computer hardware and test-and-measurement gear, including RS-232, GPIB, and LAN interfaces. Pricing and Availability The U.S. list price for the TestWave product is $5,000 for a single-user, node-locked license. The product is currently in final test, and first customer shipments are planned for April, 2003. The TestWave module is an option to Microwave Office and VSS design suites, which are sold separately with U.S. list prices starting at $15,000. For more information about the company and its products, please visit www.mwoffice.com or call (310) 726-3000. Applied Wave Research, Inc. 1960 East Grand Ave. Suite 430 El Segundo, CA 90245 FAX: (310) 726-3005 E-mail: info@mwoffice.com

Applied Wave Research's (AWR) new TestWave software is an option to the company's existing Microwave Office Design Suite and Visual System Simulator 2002 (VSS2002) simulation packages. As the press release notes, this $5,000 add-on is an option to the predecessor $15,000 package. In operation, all of this software will let you analyze RF systems end-to-end, from an antenna port through a block diagram to the RF amplifier and even DSP sections. It will even accommodate parts of optical-communication systems. The system can model and test almost any modulation scheme, including AM and FM, as well as orthogonal frequency-division-multiplex (OFDM) modulation, quadrature amplitude modulation (QAM), and phase-shift keying (PSK) and minimum-shift keying (MSK). Not mentioned in the press release is the fact that these new and existing executables run on PC platforms. A typical system would require Windows 98, Windows Me, Windows NT4, Windows 2000, or Windows XP. Even for a demo version, your Pentium hardware must clock at least 200 MHz, and you'll need 32 Mbytes of DRAM and 50 megs of spare capacity on your hard drive. Recommended is a Pentium III with 128 Mbytes of memory and 150 megs of free disk space. For its part, the VSS2002 EDA tool lets you predict RF chain impairments. Handling modulated signals, it works as an envelope simulator using supplied behavioral models or actual circuits designed in the company's Microwave Office 2002 package. As you'd expect, the VSS user interface creates a consistent human interface as the Microwave Office 2002 bits. VSS is a library of behavioral blocks for simulating RF transmitters and receivers, as well as communication channels, encoders, and decoders. These validated VSS blocks are in Microsoft C++, and therefore run IEEE double-precision math. Melding External Data VSS also gives you a means to read in external data such as AM/AM, AM/PM, intermodulation tables, phase noise profiles, data files, and S-parameters. Hierarchical designs are also supported through the use of so-called subnets. In use, special buffered block-processing manages the flow of data between blocks, acting as a data-driven simulator. The system's interconnects can automatically do things such as ensure proper alignment of data prior to performing a simulation. These interconnects also support asynchronous data transfers for multi-rate processing. To avoid issues associated with feedback loops in data-driven simulation tools, VSS blocks can also be programmed to run on a sample-per-sample basis. An example that AWR provides uses VSS' multilevel QAM (MQAM) modulated signal block to generate a 16-QAM root-raised cosine pulse-shaped signal to replicate a signal used in a broadband wireless application. In this example, the MQAM gives a choice of pulse-shaping filters as well as constellation size, and the output of the MQAM block is used to drive a VSS behavioral level mixer. In the example, a mixer model also accounts for the phase noise of the system's LO (local oscillator). VSS lets you import a phase-noise mask defined in terms of carrier offset and dBc directly into a 1/f noise block. The 1/f noise block, in turn, is used as an external source to the mixer. In this example AWR puts a mixer block into the block diagram, one that's dependent on a harmonic balance simulation of the actual circuit designed in Microwave Office. The output of the mixer is then filtered using a bandpass filter generated from an external frequency response. After filtering, the signal is passed to a nonlinear block that's dependent on the AM/AM and AM/PM characteristics of a harmonic balance simulation of the amplifier from Microwave Office. The channel model used in this example is an additive white Gaussian noise (AWGN) block. Finally, the signal is passed to VSS's coherent receiver block. It automatically sets its parameter values to the same settings as a transmitter, giving you the capability of changing the settings of the transmitter without worrying about the settings of the receiver. As such simulations run, you can look at time-domain waveforms at various points, as well as look at a constellation diagram. You can also monitor the spectrum of the mixer's output relative to the spectrum of the filtered and amplified signal. Linear and Nonlinear Simulations Microwave Office 2002 also combines linear and nonlinear circuit simulation with EM (electromagnetic) analysis and layout. The software also includes so-called Filter Synthesis and Load Pull Wizards. These Wizards incorporate measured and simulated load-pull contours. The bits also handle oscillator phase-noise analysis, and do 3D planar electromagnetic simulation. The Filter Synthesis Wizard lets you generate lumped-element or distributed filters, including ideal transmission lines and physical structures. The filter wizard can also synthesize Chebychev, Butterworth, and Bessel filters, as well as quasi-elliptic, linear phase and other types. With the Load Pull Wizard, the main independent parameter of a measurement is the source or load impedance presented to your DUT (device under test) at either a fundamental frequency or a harmonic. These impedances are generated by a virtual tuner that sweeps the impedance over a range of values. The Microwave Office suite also lets you pop in measured load-pull data from either Focus Microwave or Maury Microwave load-pull systems. The imported data provide you with a target area on a Smith chart to ease design of impedance-matching networks. Hardware In the Loop Let's return to the TestWave software, where actual hardware can be placed in the loop. This part of AWR's unified software will work with equipment that supports RS-232 connectivity or can inherently operate on a LAN. Otherwise you can install an IEEE-488 card in your host PC, using either a PCI bus card, or even a Universal Serial Bus (USB) or PCMCIA PC Card plug-in. Once configured, you can then marry your design process with simulation, signal generation, and target test-and-measurement equipment, selecting your instruments from a Windows menu in TestWave. click for full-size image You can pull in equipment such as signal generators and modulation analyzers. An instrument-interface wizard, accessible from the AWR Design Environment, then lets you interchange data dynamically between the system's simulations and your actual test hardware. AWR's approach accommodates industry-standard data formats for S-parameters, spur tables, amplifier compression curves, and the like. Microwave Office Simulation Software encompasses a network analyzer, a spectrum analyzer, and an oscilloscope, as well as a pulse-power meter, modulation analyzer, and noise-figure analyzer. The table shows the equipment that can be accommodated by the Visual System Simulator and TestWave combo. click for full-size table In use, signals can be simulated and then exported from VSS into a real signal generator, for example, which could then drive your DUT. The measured data from the DUT could then be ported back into the software and compared with simulation results of the hardware's model. Starting with hardware, real-world signals can be imported into the VSS software and used to drive simulation models with real-world signals generated from actual test equipment. This bidirectionality is really what makes this system sing. With its rich library of models, and numerous engines for RF, analog, and digital system analysis, plus the ability to marry a lot of test hardware seamlessly to the PC, this new software should go a long way to speed the design of communications systems. AWR also supports these products on the Web, with numerous application notes, patches, and downloads (however, the company requires that you register to gain access to these bits, even on a trial basis, or if you only wish to peruse the tech notes).

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