Today’s engineering environments are fraught with limited resources, tight schedules, and dramatic learning curves. One of the most important customer responsibilities we have as suppliers or distributors is to help simplify or lessen these constrictions.

Development boards, EDA software tools, and reference designs have long been the traditional tools for design engineers. But compiling these configurations does not relieve stress in critical areas, and more than likely can intensify the problem. Reducing time is the common critical element, and accelerating the development cycle should become an engineer’s prime objective.

Nu Horizons Electronics Corp. has formed an exclusive partnership with Xilinx® to provide a complete online evaluation and development environment using TechOnLine™ VirtuaLab™ technology. Rather than waiting for parts and boards, you can now can evaluate the latest Xilinx technology, learn new tools, and take real measurements at the click of a button.

How VirtuaLab Works
TechOnLine has served the educational needs of the engineering community since 1995. Their solutions are designed to build awareness, educate and train audiences, and enable the real-time evaluation of hardware and software products over the Internet.

VirtuaLab goes beyond the software simulation usually associated with web-based design; you can access hardware and software with just a browser. From virtually anywhere in the world, design engineers with an Internet connection can experience the advantages of designing Xilinx DSP solutions with the Xilinx/Nu Horizons VirtuaLab.

When you begin a VirtuaLab session, you can be assured of a consistent experience and a controlled environment. You can schedule time on VirtuaLab 24/7 according to your local time zone, and the scheduled date can be integrated into your Microsoft™ Outlook calendar.

The first user interface is very familiar: a Windows™ or Linux™ desktop on which locally stored files can be moved onto an LDAP (lightweight directory access protocol) environment on TechOnLine’s servers. In this way, benchmarks, applications under development, and other proprietary software can be run on the target board, within a personalized file structure. Security is always a top priority.

From the Windows desktop, you move to the remote target control interface, which provides remote control of the hardware with the same capabilities you would have as if the board was connected to your local PC. Additional functionalities include the ability to:

• Reset the platform
• Power-cycle the platform
• View a Web-cam display of the VirtuaLab
• Control voltage
• View a component description
• Observe LEDs
• Utilize a virtual touch screen

An innovative support feature called “shadowing” allows Nu Horizons’ field applications engineers to log into your session, providing you with technical assistance if needed.

The Nu Horizons/Xilinx VirtuaLab
Architects and designers can reserve exclusive blocks of time by simply logging onto VirtuaLab.TechOnLine.com to register. You can select one of three types of interactive VirtuaLab experiences:

1. New Xilinx user – Although technically astute, you have not been exposed to either the development tool flow or the Xilinx FPGA architecture.
2. Xilinx-aware user – You have designed with previous Xilinx products but may not know about the latest solutions.
3. Expert Xilinx user – You are proficient in both standard and advanced products architecture, and are licensed in most or all of the EDA design tools available for development.

Once in the VirtuaLab environment, you can compile code, measure board performance, and set breakpoints – anything that you could do if the evaluation board was being controlled by your own PC.

What Can I Evaluate?
Working with Xilinx, the Nu Horizons engineering teams offer a full portfolio of educational aids, as well as direct access to Xilinx design flow tools and high-speed test equipment.

Our first laboratory consists of the Nu Horizons Spartan-3™-2000 evaluation platform (Figure 1), which is a very flexible testing platform that allows you to evaluate the Xilinx XC3S2000 FPGA and develop a multitude of applications. One of the Nu Horizons/Xilinx VirtuaLab applications is focused on high-performance FPGA DSP functionality.

You can develop advanced algorithms and perform complex measurements through a full complement of test equipment connected to the Spartan-3-2000 environment. Both a signal/pattern generator and high-speed oscilloscope are connected to high-speed analog-to-digital converter (ADC) and digital-to-analog converter (DAC) modules, and each piece of Agilent™ test equipment is placed in the host mode so you can remotely manage the equipment’s front panel controls. You can save settings and scripts easily within your I- or H-drive private folders to re-use for future sessions.

Having real signal insertion and being able to measure real output means that you can validate your algorithms, transforms, and functions, and simultaneously have confidence that all results are both precise and authentic.

Reference DSP designs are provided within the VirtuaLab. These designs allow you to evaluate the Spartan-3-2000 FPGA in a pre-verified environment. Reference designs include:

• Existing System Generator tutorial to introduce engineers to other features such as the ChipScope™ tool, HDL co-simulation, hardware co-simulation, and the PicoBlaze™ processor.
• Simple FFT with a 256-tap FIR filter and interpolation by three. Ease of use and reasonably high performance allow you to evaluate the tool interface as well as the hardware. The filter design is provided using the FDA tool to generate the coefficients, allowing you to modify the coefficients and view the results. Simulation can be run in System Generator, as well as live in hardware.
• Equalized 16-QAM demodulator, including the adaptive filter. The receiver architecture provides subsystems that demonstrate adaptive channel equalization and carrier tracking on a random QAM data source.

ADC Platform Solution
The Nu Horizons Spartan-3-2000 evaluation platform includes a mid-range ADC on the main platform. You can use the Linear Technology™ LTC1865L 16-bit 150 ksps ADC in ratio metric applications, or with external references. The highimpedance analog inputs and the ability to operate with reduced spans down to 1V full scale allow direct connection to signal sources in many applications – eliminating the need for external gain stages.

High-Performance A/D Acquisition Module
The high-performance ADC acquisition modules interface directly to the Nu Horizons Spartan-3-2000 evaluation platform also provided by Linear Technology. These ADC development boards offer 12-14 bits of resolution, and sampling rates from 25-40 MHz.

The Linear Technology ADC development boards (see Table 1) are designed to digitize high-frequency, wide-dynamic range signals. These boards target applications such as telecommunications, digital imaging, spectrum analysis, and cellular base stations.

Table 1 – Linear Technology high-speed acquisition modules 25-80 Msps

520B-A	LTC1748	14-bit	80 Msps	Ain < 40 MHz
520B-B	LTC1748	14-bit	80 Msps	Ain > 40 MHz
520B-C	LTC1745	12-bit	25 Msps	Ain < 40 MHz
520B-D	LTC1746	14-bit	25 Msps	Ain < 40 MHz
520B-E	LTC1747	12-bit	80 Msps	Ain < 40 MHz
520B-F	LTC1747	12-bit	65 Msps	Ain > 40 MHz
520B-G	LTC1742	14-bit	65 Msps	Ain < 40 MHz
520B-H	LTC1742	14-bit	65 Msps	Ain > 40 MHz
520B-I	LTC1741	12-bit	65 Msps	Ain < 40 MHz
520B-J	LTC1741	12-bit	65 Msps	Ain > 40 MHz
520B-K	LTC1743	12- bit	50 Msps	Ain < 40 MHz

DAC Platform Solution
The Spartan-3-2000 evaluation platform includes Linear Technology’s LTC1654L 14-bit, 8 conversion rate DAC. The LTC1654 is a dual rail-to-rail voltage output 14-bit DAC that includes output buffer amplifiers and a flexible serial interface. The LTC1654L has two programmable speeds: a fast and slow mode with ±1 LSB settling times of 3.5 ms or 8 ms, respectively, and supply currents of 750 mA and 450 mA in the two modes. The LTC1654 also has shut-down capability, power-on reset, and a clear function to 0V.

High-Performance DAC Module
The Spartan-3-2000 evaluation platform includes an interface to Intersil™ high-speed DAC ISL5x29EVAL1 evaluation modules (see Table 2).

Table 2 – Intersil high-speed conversion modules

ISL5629EVAL1	2 x 8	210 MHz
ISL5729EVAL1	2 x 10	210 MHz
ISL5829EVAL1	2 x 12	210 MHz
ISL5929EVAL1	2 x 14	210 MHz

You can develop high-performance DSP applications, such as quadrature transmit with an IF range of 0-80 MHz and medical/test instrumentation and equipment. You can evaluate the Intersil technology in conjunction with the Xilinx Spartan-3 FPGA in high-performance DSP designs. Figure 2 illustrates how you can load a DSP application, provide signal insertion, and measure output waveform.

Conclusion
Today’s semiconductor industry is largely driven by new technologies that are barely available, and aggressive development schedules that utilize these new technologies. Suppliers and distributors typically deliver boxes of building blocks, and if the design engineer works many extra hours assembling the pieces, they may wonder if this new technology can even perform the task at hand.

Nu Horizons and Xilinx have looked closely at the challenge of limited resources, tight schedules, and dramatic learning curves and built an approach with TechOnLine’s VirtuaLab that provides you with a time-saving, innovative, and zero-cost solution to evaluating technology.

In addition to its primary use by engineers, the VirtuaLab can help other departments as well. Online product evaluation, sales demonstrations, and internal training are example applications of VirtuaLab technology. Each VirtuaLab is delivered with a range of tools including a product tutorial or quick start script – enabling novices to exercise the hardware without writing any code, or a complete IDE for the expert expecting a full-featured experience.

For more information, visit the Nu Horizons/Xilinx VirtuaLab at VirtuaLab. TechOnLine.com or contact your local Nu Horizons sales representative.

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