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Signal capture and analysis over broad instantaneous bandwidths is vital for military forces knowing “what’s out there” in terms of potential threats. Detecting signals from missile guidance, radar, and other military electronic systems can provide much-needed warnings about their presence, and even their locations. Fortunately, collaborative efforts by two key instrument suppliers have led to an effective solution for wideband signal analysis.

The model IQC5255B RF record and playback system from X-Com Systems and the N9040B UXA Series signal analyzer from Keysight Technologies combine to form a powerful measurement system—one that can capture, analyze, and characterize signals within a 255-MHz instantaneous bandwidth with 16-b resolution at frequencies to 50 GHz, and for periods of time ranging from seconds to days.

Fig. 1Since the dissolution of the Soviet Union, the United States has faced few challenges to its stated “spectrum dominance.” Consequently, the military could operate more or less with impunity on the ground, in the air, and at sea thanks in large measure to advanced electronic warfare (EW) capabilities. This level of confidence came to an abrupt end—at least for ground-based operations—when Russia revealed its well-orchestrated, advanced arsenal of EW assets in Crimea, Ukraine, and (most recently) Syria, which the Pentagon called an “eye-watering” revelation.

The result has been a major reassessment of U.S. EW capabilities, as the Army in particular has long largely ignored nonkinetic defense—except for its rapid insertion in the mid-2000s of jammers to counter the deadly effects of Radio-Controlled Improvised Explosive Devices (RC-IEDs).

A crucial need for advancing the performance of current EW systems is the capability to detect, analyze, and counter threats. This is a far more difficult challenge today: The frequency spectrum is densely packed with signals over a wide range of frequencies, and threats are far more complex and more easily obscured in such environments.

For effective signal intelligence (SIGINT) to take place, a number of things must happen. It is necessary to capture signals within wide instantaneous bandwidths of interest over long periods; digitize those signals without errors; separate signals of interest from clutter and known signals; analyze potential threat signal waveforms in detail; create electronic countermeasures (ECM) to defuse them; incorporate them in an EW system; and, finally, test their viability against the original threats.

The aforementioned system recently introduced by X-COM Systems and Keysight Technologies is designed to perform many of these required tasks, using commercial-off-the-shelf (COTS) instruments for conducting as much signal capture, simulation, analysis, and testing as early in the design process as possible.

The system can additionally subject a candidate EW system to a broad array of signal types with constantly-changing waveforms over a wide bandwidth, at the same time inserting interference, known threats, and other impediments. Rather than attempting to replace the larger, more comprehensive (and much more expensive) systems used later in the EW system validation process, it can dramatically reduce the amount of testing required at that stage.

The system consists of the new model IQC5255B (see figure) from X-COM Systems, the latest model in the company’s IQC5000 Series of RF record and playback systems, combined with the new model N9040B UXA Series signal analyzer from Keysight Technologies. The instruments together expand the instantaneous signal-capture system bandwidth to 255 MHz. The compact, lightweight IQC5255B record and playback system measures only 12 × 5.25 × 10.5 in. and weighs less than 15 lb., so it can be used in the field as well as in laboratory and production environments.

Files of captured signal data can be examined using signal analysis and characterization tools from both X-COM Systems and Keysight Technologies (see Defense Electronics, February 2016, p. 81). As a stand-alone instrument, typical applications for the IQC5255B are recording, storing, and playing back RF signals for threat analysis and building libraries, as well as in the validation of EW, radar, and communications systems, plus interference analysis and spectrum monitoring and management.

When combined with a UXA Series signal analyzer, the instruments collectively become an integrated, comprehensive, COTS-type solution for capturing, analyzing, and characterizing signals over periods from seconds to days, with very high resolution of 16 b at carrier frequencies to 50 GHz with 100% probability of intercept.

When combined with the N9040B UXA series signal analyzer, the IQC5255B has spurious-free dynamic range (SFDR) of 78 dB over its 255 MHz bandwidth, making it possible to detect very weak signals in the presence of multiple stronger signals; this is an increasingly critical metric when used in congested signal environments. Detailed specifications are shown in the table.

TableWhen recording a single channel at this bandwidth, the system can continuously record and play back more than 50 minutes of uninterrupted in-phase/quadrature (I/Q) signal data in a single channel, or more than 40 minutes of two time-synchronous channels at 160-MHz bandwidth.

By adding external data packs to a maximum of 15 TB, the IQC5255B will continuously record or play back a single channel for more than three hours at full bandwidth. The instrument’s dual-channel record and playback capability makes it possible for users to note differences in timing between the two data streams to evaluate overall system performance.

The IQC5255B was designed to work seamlessly with the UXA Series analyzers, the latter acting as a single point of control for both instruments. All IQC5255B functions are orchestrated directly by the signal analyzer. This eliminates the need for an external controller such as a laptop computer, along with associated cables, System setup and operation are thus simplified— a major benefit when used in secure locations where a laptop computer invariably presents security problems.

The powerful computer in the UXA Series instruments can also incorporate and run X-COM’s comprehensive and recently-updated Spectro-X signal analysis software, as well as its RF Editor drag-and drop graphical editing tool, Keysight’s 89600B vector signal analysis software, and The Mathworks’ MATLAB. Spectro-X can simultaneously analyze up to four files of any size over any range of frequencies with file alignment of ±1 sample, allowing the user to “zoom in” to signals of interest contained within files containing hundreds of thousands of emitters.

The IQC5255B can also offload signal files via eight lanes of PCIe 2.0 at greater than 800 MB/s (about 48 GB/minute), which significantly reduces the amount of time required to transfer large signal capture files to a workstation environment. It provides precise event triggering with Global-Positioning-System (GPS) and IRIG-B event stamps that add situational awareness to the data, allowing signals of interest to be more easily located even in very large data files.

The IQC5000B also includes I and Q analog outputs, so it can replay all or any part of the recorded spectrum with full 16-b I and Q precision using any Keysight Technologies vector signal generator (VSG). These capabilities make it possible to stress and margin test designs in a controlled environment. 

X-COM Systems, LLC, 12345-B Sunrise Valley Dr., Reston, VA 20191; (571) 612-5490

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