Rising consumer demands and expectations have driven manufacturers to develop newer, more feature-rich innovative products to maintain their competitive edge and profitability. Telematics systems in automobiles are a prime example of this increasing functionality. A few years ago, cars were only equipped with cassette players and AM/FM radios. Then came optical discs, and automakers immediately integrated CD players and standard AM/FM radios and cassette players into their vehicles. Consumer demands and expectations have continued to rise, and now it's common to see telematics systems incorporating CD/MP3 players, DVD players, AM/FM and satellite radio, GPS, and cellular phones. All these technologies, previously implemented in separate devices, can now be integrated into a sophisticated and complex telematics system. [align=center]Figure 1. Key points on the frequency-resolution curve of the NI PXI-5922 multi-resolution digital converter[/align] This technological convergence allows automakers to meet user expectations and maintain a competitive market position. However, this places immense pressure on R&D personnel and test engineers, who need to test more features while minimizing testing time to meet time-to-market requirements. Let's look at it from the automaker's perspective. First, consider the costs required to design and develop a telematics system. A few years ago, designers might have only needed a traditional boxed instrument to design and test the limited functionality of a cassette player. However, to meet today's challenges, designers must purchase new instruments to test new features in telematics systems. As test systems continue to expand, not only is space insufficient, but expenses also exceed budgets. Wouldn't it be great to replace all these expensive and varied instruments with an integrated test system that allows for application-specific functionality definition and provides future expansion capabilities? Today, virtual instrumentation has become the preferred test solution for overcoming these challenges. It combines rapid software development with highly flexible modular hardware to create user-defined test systems. Virtual instrumentation offers: intuitive software tools for rapid test development; fast, accurate, modular I/O based on innovative commercial technologies; and a PC platform providing high accuracy and high throughput with integrated synchronization capabilities. Rapid Test Development Software As automation becomes a fundamental requirement for rapidly testing complex products, software has become an essential component of all test systems, from design verification to highly automated manufacturing testing. To quickly deliver test systems capable of testing new features, an integrated set of test development tools is needed. These tools include test management, test development, and I/O drivers. [align=center]Figure 2. PX-5922 Frequency-Resolution Curve Compared to Other Digital Converters at Sampling Rates Up to 15 MS/s[/align] PC-Based Test Platform All modern test systems incorporate a PC. The PC is no longer just part of the test system, but is increasingly becoming an important integrated platform: the test system hub. Gigabit processors, high-speed buses, widespread software availability, continuously improving performance, and exceptionally low prices make the PC an ideal test platform. If we examine the performance evolution of PCs over the past 20 years, the only component in the test system with a similarly significant performance improvement is the device under test (DUT). General-Purpose Instruments for Dynamic Testing Suppose you are testing the audio and wireless functions of an in-vehicle infotainment system. The instruments required to perform audio and wireless testing are an audio analyzer, an RF downconverter, and an IF digital converter. You could choose three PXI or PCI modules and define the test system using software. It is obviously more beneficial if a single device can be used for multiple purposes. This can now be achieved using general-purpose instruments for dynamic measurements. The National Instruments (NI) PXI-5922 multi-resolution digitizer is one such device that integrates multiple instrument functions into a single module. This digitizer allows users to adjust the sampling rate to achieve different resolutions. For example, at a sampling rate of 15 MS/s, the module provides 16-bit resolution; by reducing the sampling rate to 500 kS/s via software, the same module (without any hardware modifications) will provide 24-bit resolution. In this example, the PXI-5992 general-purpose instrument can be used as both a 24-bit audio analyzer and a 16-bit intermediate frequency digitizer. [align=center] Figure 3. Pure sine wave FFT plots applied to a 6-bit Δ-Σ ADC before and after linearization[/align] Just as the DMM integrates multiple DC measurement functions into a single instrument, the PXI-5992 improves AC measurement capabilities by providing multiple instrument functions within a single digitizer. New virtual instruments can be created using this digitizer and software such as LabVIEW 8. Compared to many traditional instruments such as audio analyzers, spectrum analyzers, intermediate frequency and I/Q baseband digital converters, DC and RMS voltmeters, and frequency counters, this virtual instrument offers superior measurement performance. Innovative Flex II ADC Multi-Resolution Technology This innovative multi-resolution technology is implemented using NI's Flex II ADC. This analog-to-digital converter, based on a fully custom analog ASIC designed by NI, is an enhanced Δ-Σ converter that achieves exceptionally high dynamic range across a wide range of sampling rates using two innovative technologies: replacing the single-bit Δ-Σ ADC with a 6-bit Δ-Σ ADC; and a patented digital linearization mechanism. While single-bit Δ-Σ ADCs provide high resolution and high dynamic range for low-frequency applications, their limited sampling speed makes them unsuitable for applications with dynamic signal frequencies exceeding hundreds of kHz. Multi-bit Δ-Σ ADCs, on the other hand, offer high dynamic range at high frequencies, and linearization removes the inherent nonlinearity of multi-bit Δ-Σ ADCs. Figure 3 illustrates how nonlinearity in the ADC manifests as harmonics in the frequency domain. The Flex II ADC uses powerful FPGAs and patented linearization technology to digitally eliminate these nonlinearities and provides a wide dynamic range over a high sampling rate range. This increased dynamic range enables users to analyze signals that would previously be smeared by noise in conventional instruments. [align=center] Figure 4. High-end generator produces a very pure 10kHz sine wave FFT capture with noise levels as low as -170dB FS/Hz and SFDR as high as -120dBc[/align] The Flex II ADC is a great invention, but it doesn't function properly if engineers cannot integrate it into digitizing instruments without compromising performance. The PXI-5922 multi-resolution digitizer, with its best-in-class front-end module, fully utilizes the high-performance capabilities of the Flex II ADC, unleashing the digitizer's effective resources to deliver powerful performance. This digitizer offers the highest resolution and the largest dynamic range on the market. Therefore, it can be used not only as a general-purpose instrument but also provides superior dynamic performance compared to the various standalone instruments it can replace. Figure 4 shows a very pure 10kHz sine wave FFT capture produced by the high-end generator. The PXI-5922 can achieve noise densities as low as -170 dB FS/Hz, and in this example, the SFDR can reach as high as -120 dBc.