Electronic Design

Handheld Real-Time Spectrum Analyzers Nail Interfering Wireless Signals Fast

Complex wireless technologies make measurement a real challenge with their short bursts and non-deterministic timing. There’s the 625-µs Bluetooth hop interval and the 70-ns hop interval of Ultra-Wideband (UWB), not to mention the short packet bursts of 5 ms for wireless local-area networks (WLANs), 359 µs for Bluetooth, and 10 µs for UWB. Furthermore, identifying and locating interfering RF emitters that are misusing the radio spectrum has become more of a challenge.

Yet Tektronix’s SA2600 and H600 Hawk Real-Time Spectrum Analyzers can meet both of these measurement challenges (see the figure). Using the company’s special DPX technology, these portable handheld spectrum analyzers target radio repair depots, spectrum interference management specialists, and designers in the surveillance and security business.

Both units can be used to quickly classify and locate the source of disruptive or illegal signals from wireless bugs, malicious remote-control RF links, illicit wireless activities, and unintentional emission sources. Typically the time to response and the minimization of detection risk are key issues in tracking down these wireless bandits. Designed for rugged field use, the rubberized magnesium alloy case can withstand drops and other mistreatment. Each unit can operate up to five hours continuously on a single battery charge.

Discovering, capturing, and analyzing wireless transients requires special instrument features. These include a sufficiently large capture bandwidth, a high analog-to-digital converter (ADC) sampling rate to exceed the Nyquist criteria for the desired capture bandwidth, a long enough analysis interval to support the narrowest-resolution bandwidth, and a fast discrete Fourier transform (DFT) rate to support the minimum event duration. Bench instruments like the Tektronix RSA3000B and RSA6100A can handle these tasks, but the SA2600 and H600 do the job as well.

The SA2600 and H600 also have Tektronix’s DPX technology, which is the key to transforming the tons of data that a real-time spectrum analyzer captures into a useful display. The DPX waveform image processing technology produces a live RF spectrum display to provide engineers a view of RF signal instabilities and transients that no one could see before.

These spectrum analyzers convert the input time-domain signals into the frequency domain, where DFT computations extract the details for display, at extremely high rates. This minimizes the analysis gaps inherent in swept-spectrum and vector signal analyzers. It also allows frequent and infrequent events to be prominently displayed. The unique color-graded persistence display holds the anomalies until they can be seen, making it possible to see elusive glitches and other transient events.

With each screen update, the power levels at each frequency across the capture bandwidth are recorded. Varying colors on the display show the incidence of power over time at each frequency. The result is that the enormous amount of data collected is boiled down into an easily interpreted screen presentation, providing the insight to detect and diagnose the wide range of wireless signal possibilities.

The SA2600 has a basic frequency range of 10 kHz to 6.2 GHz and a real-time bandwidth of 20 MHz. Its displayed average noise level is –153 dBm. Also, it has a 100% probability of intercept (POI) event duration of 500 µs, while the 100% POI for the H600 is 125 µs. Both analyzers come with a built-in GPS receiver and integrated GPS mapping software that permits fast interference location.

The base price for the SA2600 is $22,900, and the H600 is $38,900. These units are available for order.

Tektronix Inc.


TAGS: Components
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