Signal Analyzer Aids Embedded Designers Facing RF Challenges

Jan. 28, 2011
Tektronix's RSA5000, billed as the first real-time signal analyzer, could be the ticket for embedded designers looking to debug RF functionality in their system designs.

RSA5000 series

With embedded systems now incorporating a growing amount of RF-related functionality, designers are more in need than ever of tools and test gear that address RF issues. RF circuitry can be found in automotive systems, home-automation systems, and green-energy systems. Moreover, this RF content is typically situated in close quarters with digital circuitry, resulting in integration and electromagnetic-compatibility (EMC) challenges.

One answer to this design conundrum is available in the form of Tektronix’s RSA5000 signal analyzer, billed as the industry’s first real-time signal analyzer (see the figure). The mid-range instrument incorporates the third generation of Tek’s digital phosphor technology (DPX) and sports an 85-MHz acquisition bandwidth. Banner specifications include superior low-frequency performance with phase noise of -131 dBc/Hz at 10-kHz offset and -150-dBm displayed average noise level (DANL) at a 10-MHz carrier frequency.

First introduced in 2006 and revamped in a second generation 18 months ago, DPX technology first performs a digital conversion to analog RF waveforms. Next, a discrete Fourier transform is applied to obtain a spectrum image. In the third generation of DPX technology, it’s now applied to multiple domains: amplitude, frequency, or phase versus time. In doing so, the display updates at up to 50,000 waveforms/s; this approximates zero-span technology but is in fact 1000 times faster than zero-span technology for amplitude-vs.-time measurements. As a result, the instrument can find and measure RF-amplitude transients that other analyzers can miss.

What is new in the RSA5000 for signal analyzers is its ability to apply DPX in the frequency-vs.-time and phase-vs.-time modes. With DPX available in multiple domains, users can find and measure phase or frequency transients that won’t turn up in post-processed vector signal analyzer (VSA) analysis. Further, the addition of a frequency-edge trigger enables one to look at a very specific frequency crossing and be able to trigger on that signal. This is an important capability for embedded-RF designers who are performing analyses on frequency-hopping designs, as well as for spectrum-management applications that require power and frequency monitoring of short- and long-term events.

The RSA5000 should fulfill most requirements for a real-time spectrum/signal analyzer, given its DPX capabilities and minimum signal duration of 5.8 µs. It can perform swept-DPX analyses, enabling users to sweep the instrument’s full frequency range with live RF. Further, it can capture up to 7 s of signal at full 85-MHz bandwidth. That’s enough to capture the entire setup period of a Bluetooth transaction that is hopping across that entire 85-MHz spectrum.

Embedded-RF designers, or those doing electromagnetic interference (EMI) diagnostics, will also benefit from visibility into the instrument’s full bandwidth. This can aid with debugging jamming (or self-jamming) issues. In radio-communication design tasks, the instrument’s RF performance acquits itself well. Being able to see the entire 75-MHz bandwidth of a cellular receiver, for example, is a handy capability to have. As a tool for spectrum management and monitoring, the instrument’s real-time monitoring of 85-MHz bandwidths means a 100% probability of intercept for signals as brief as 6 µs.

The RSA5000 series signal analyzers are available now with prices starting at $34,900.

Tektronix

About the Author

David Maliniak | MWRF Executive Editor

In his long career in the B2B electronics-industry media, David Maliniak has held editorial roles as both generalist and specialist. As Components Editor and, later, as Editor in Chief of EE Product News, David gained breadth of experience in covering the industry at large. In serving as EDA/Test and Measurement Technology Editor at Electronic Design, he developed deep insight into those complex areas of technology. Most recently, David worked in technical marketing communications at Teledyne LeCroy. David earned a B.A. in journalism at New York University.

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