Increasing the realism of radar testing with an advanced signal scenario generator
In response to these needs, developers are turning to standardized products as the building blocks for new designs and new test systems. This is enabled by today’s evolving digital technologies, which provide a foundation for greater flexibility, smaller size and lower costs.
Packing more capability into a test system
Thorough verification of radar system performance requires the creation of realistic signal scenarios that push a design to its limits. The optimum test system will minimize the need for costly flight testing by emulating a variety of flyover conditions in their entirety.
An arbitrary waveform generator (AWG) is typically the signal source of choice. Two of the key requirements are small pulses and long playback times. At first blush, the right solution may appear to be a wide-bandwidth AWG with an ample amount of built-in memory. However, two additional attributes are crucial. First, high resolution at wide bandwidth enables the creation of highly accurate signal scenarios. Second, advanced sequencing capabilities ensure efficient use of available memory while creating highly complex simulations.
All of these capabilities are built into the Agilent M8190A signal scenario generator (SSG). Based on patented digital-to-analog converter (DAC) technology, the M8190A raises the bar with 14-bit resolution at 8 GSa/s or 12-bit resolution at 12 GSa/s. The unit can easily switch between those modes to meet the needs of different applications. It is also precise enough to serve as the modulation source for an RF/microwave signal generator.
The M8190A SSG can be configured with 128 MSa (standard) to 2 GSa (optional) of waveform memory per output channel. With 2 GSa installed, the maximum playback time is 1.6 s at the highest frequency. The absolute amount of waveform memory is important; however, using the available memory efficiently enables a concept called memory gain. Unlike typical AWGs, the M8190A offers advanced sequencing capabilities such as stepping, looping and conditional jumping. This makes it possible to create repeated segments once and then reuse them programmatically as needed. These capabilities can be applied to waveforms or waveform sequences.
Sketching a versatile test setup
A typical test system configuration will help illustrate the value of the M8190A SSG. In addition to the SSG, the other instruments in the example system are a wide-bandwidth oscilloscope, a signal analyzer and an RF/microwave signal generator, which also serves as an upconverter (Figure 1).
Agilent’s recommended configuration includes a 44-GHz Agilent E8257D PSG analog signal generator, 50-GHz Agilent Infiniium DSO90000A Series high-performance oscilloscope, 50-GHz E4448A PSA Series spectrum analyzer (with Agilent 89600B vector signal analysis software) and the M8190A SSG. Within this system, the M8190A adds its unique combination of resolution and bandwidth, enabling developers to push their radar designs to the limit and extract new insights about system performance.
This system is capable of producing the radar LFM chirp shown in Figure 2. In the bottom-right trace, a frequency-versus-time display illustrates the performance of the M8190A across a 2-GHz frequency span.
Conclusion
Successful delivery of future radar systems depends on the ability to increase system capability while shrinking overall size, reducing costs and accelerating time-to-market. The same is true for the test system used to characterize radar accuracy and performance. The most cost-effective way to satisfy these needs is through the use of standardized products in both the radar and its test system. Through advances in digital technology, “standardized” is no longer synonymous with “limited functionality.” The Agilent M8190A SSG embodies this new direction: Even though the M8190A is a standardized product, it provides the signal fidelity and functional versatility needed to address a wide range of present and future testing requirements.
The author
Beate Hoehne is the Product Manager for Pulse Pattern Generators, Digital Test Division, Agilent Technologies. Beate Hoehne designs and implements marketing strategies for the most comprehensive pulse and data generator product portfolio for Agilent Technologies’ Digital Verification Solutions Division. Beate is responsible for the marketing activities along the entire product life cycle.
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