Real-time RF signal recording/playback system captures 1 GHz spectrum slice

February 18, 2015 // By Jean-Pierre Joosting
X-COM Systems, a subsidiary of Bird Technologies, has introduced the IQC91000A, which claims to be the only RF and microwave signal recording and playback system that can capture, digitise, and store up to 1000 MHz of the electromagnetic spectrum in real time without gaps and missed signal events within any frequency range from 500 MHz to 18 GHz with 50 dB of spurious-free dynamic range.

The entire 1000-MHz signal capture file or selected portions of it can be regenerated and played back at virtually any desired centre frequency and offloaded at high speed to a workstation for analysis. The IQC91000A is suited for signals intelligence (SIGINT) and electronic intelligence (ELINT) applications, interference detection, and testing and validation of radar, electronic warfare, and commercial and military wireless communications systems.

Unlike a swept receiver that scans the spectrum within a specific frequency range at high speed and can detect signals within it, the IQC91000A has an instantaneous (fixed) capture bandwidth of 1000 MHz that allows it to collect detailed information about the signals within it as In-phase (I) and Quadrature (Q) data. This allows detailed analysis of the signal’s characteristics to be performed using MATLAB as well as vector signal analysis tools such as the 89600 from Keysight Technologies and the Tektronix SignalVu-PC. The system supports MATLAB class definitions, so users can operate on specific data samples of interest identified by date, time, scale factor, and other parameters, and eliminates the need to manually construct the information required to access the data.

All subsystems in the IQC91000A, from signal capture to digital storage, are optimised to eliminate throughput bottlenecks that can drop samples and create potential recording gaps. The result is that recording, triggering, and data markers all perform together in real time. The IQC91000A’s receiver captures signals anywhere between 500 MHz and 18 GHz and downconverts them to an intermediate frequency whose output is digitised with 12-bit fidelity at up to 3.2 Gsamples/sec. This signal capture file is sent to the system’s internal SSDs that collectively have 30 Tbytes of capacity. This signal-capture file can then be offloaded at 600 Mbytes/sec or faster via eight lanes of PCIe 2.0 to a workstation for analysis.

For owners of Keysight instruments, the IQC91000A can be specified without its internal downconverter and can instead be used with the Keysight PXA and UXA Series signal analysers that have an IF bandwidth up to 700 MHz. For playback, the IQC91000A can be used with the Keysight PSG Series signal generators for upconversion (and playback) of recorded signals up to 44 GHz as well as the SMW200A from Rohde & Schwarz for upconversion to 20 GHz.