The RFM-1R1S18K-L1-VXS downconverter/tuner separates its 1.5-GHz bandwidth into four IF outputs, each with 375-MHz bandwidth centered at 745 MHz.
To rectify this, Mercury Systems last year proposed a standardized open-system architecture based on a “building block” approach. Called OpenRFM, the approach brings RF and microwave technology into the realm of systems-level standards such as OpenVPX, VME, and VXS commonly used by digital embedded systems for electronic-warfare (EW) and other defense electronics applications. In its continuing support of the proposed standard, the company has introduced the Ensemble RFM-1RS18 tuner available in four configurations that cover the 2-to-18-GHz frequency range commonly associated with electronic-warfare (EW) applications.
The four configurations include the single-channel models RFM-1R1S18K-L1-VXS and RFM-1R1S18K-1875-L1-VXS downconverter/tuners and the RFM-1T18K-1875-L1-VXS and RFM-1T1S18K-1875-L1-VXS transmit upconverter/tuners (see photo). The downconverter/tuners convert signals from 2 to18 GHz to a lower-frequency intermediate frequency (IF) for processing. The complementary transmit upconverter/tuners accept an IF which is converted to a user-selectable frequency in the 2-to-18-GHz range.
All four units are composed of as many as three OpenRFM modules—a wideband front-end, an IF converter, and, in three of the models, a fast-switching direct-digital synthesizer (DDS) for maintaining precise signal coherence. Each instrument packs broadband capabilities into a single-slot 6U VXS form factor. Whether employed as standalone units or paired together, these new models offer excellent performance and flexible capabilities to meet EW needs.
Model RFM-1R1S18K-L1-VXS offers 1.5-GHz instantaneous bandwidth, which is three times the industry standard. The 1.5-GHz instantaneous bandwidth split into four IF outputs each with a 375-MHz bandwidth centered at 745 MHz. By dividing the full 1.5-GHz instantaneous bandwidth into narrower swaths of bandwidth, the instrument is capable of very high signal fidelity in the digital conversion process, as the highest resolution (that is, greater effective number bits) and dynamic range are afforded by analog-to-digital converters (ADCs) with lower sampling rates and bandwidths. Consequently, the 375-MHz segments of bandwidth at each of the four outputs can be much more precisely processed than if the entire 1.5-GHz bandwidth was digitized and processed as a whole.
Dramatically reducing bandwidth also results in less data to be processed at each output and can thus be searched more rapidly for signals of interest and analyzed with less formidable processors or signal processing workstations. The Ensemble RFM-1R1S18K-1875-L1-VXS unit differs from the model RFM-1R1S18K-L1-VXS since it has a single output with 1 GHz of instantaneous bandwidth centered at 1.875 GHz. This unit is designed to take advantage of higher sampling ADCs and is well suited for applications working with digital RF memories (DRFMs) when paired with either of the transmit tuners.
Models RFM-1T18K-1875-L1-VXS and RFM-1T1S18K-1875-L1-VXS are both single-channel, single-output tuner/upconverters that accept 1 GHz of instantaneous bandwidth centered at 1.875 GHz. The 1T1S18K contains a DDS, while the 1T18K does not. The RFM-1T18K-1875-L1-VXS can be paired with the RFM-1R1S18K-1875-L1-VXS, sharing the DDS capabilities of the receive unit and ensuring locked tune frequencies.
