Wideband frequency downconverters help to process a broad range of RF and microwave frequencies when covering a great deal of spectrum in surveillance and electronic-intelligence (ELINT) applications. The SIDC 6000 series of microwave downconverters/tuners from Elcom Technologies feature extremely broad bandwidth, with a tuning range of 0.5 to 26.5 GHz in a compact 1U-high enclosure that will fit within the available space in most 19-in. racks. The fast-tuning downconverter is also well suited for use in radar-warning receivers (RWRs), in instrumentation, and in satellite-communications (satcom) systems.

The SIDC 6000 (see figure) provides 10-Hz tuning resolution over its wide input frequency range, with standard tuning speed of 1 ms from a first frequency, f1, to a second frequency, f2 (models with faster tuning speeds are available upon request). The frequency accuracy, which is tied to an internal 10-MHz reference oscillator, is better than ±0.1 ppm, with a long-term aging rate of better than ±1 ppm/year. The broadband downconverter/tuner also incorporates an input port for an external 10-MHz reference source.

The downconverter/tuner features a bright front-panel display for ease of local control, but also includes Ethernet 10/100 Base T, RS-232C, and RS-422 interfaces for flexible remote-control connections. The unit can sweep from frequency f1 to frequency f2 in programmed steps at sweep rates from 1 ms to 60 s; it can sweep across frequency as fast as 500 MHz in 1 ms. It can also stop a sweep upon detection of a signal threshold level.

For system-level processing, the SIDC 6000 provides both L-band and intermediate-frequency (IF) output ports. The L-band signals are available across a 500-MHz 3-dB bandwidth centered at 1.2 GHz with a typical monitor level of −20 dBc. The IF center frequency can be set at 70, 140, or 160 MHz. At 70 MHz, the selectable 3-dB IF bandwidths are 1, 5, 10, 20, 30, and 40 MHz. The gain flatness across those bandwidths is no worse than ±0.6 dB and typically ±0.4 dB. At 140 and 160 MHz, the downconverter/tuner offers selectable 3-dB IF bandwidths of 80 MHz minimum and 160 MHz maximum with worst-case IF gain flatness of ±0.8 dB and typical IF gain flatness of ±0.6 dB. The RF-to-IF gain through the SIDC 6000 can be set manually in 1-dB increments to a maximum amount of 42 dB. The RF gain variations are only±1.5 dB across the full RF input frequency range.

When used with an external reference oscillator, the SIDC 6000 requires a clock signal level of 0 ± 3 dBm; the downconverter/tuner automatically locks to the external clock oscillator when it is connected to the female BNC connector provided for that purpose. Otherwise, even when operating with its external reference oscillator, the SIDC 6000 boasts quite respectable phase-noise performance, with single-sideband (SSB) phase noise at a 10-GHz carrier of −68 dBc/Hz offset 100 Hz, −90 dBc/Hz offset 1 kHz, −96 dBc/Hz offset 10 kHz, −104 dBc/Hz offset 100 kHz, 0115 dBc/Hz offset 1 MHz, and −140 dBc/Hz at the noise floor (offset 10 MHz). The downconverter/tuner’s RF section handles maximum RF input signals to +20 dBm, with selectable inverting/non-inverting conversion sense for IF outputs. The maximum noise figure for the RF section is 17 dB from 0.5 to 1.0 GHz, but 15 dB for inputs from 1.0 to 26.5 GHz.

The downconverter/tuner provides greater than 70-dB image rejection and achieves a spurious-free dynamic range (SFDR) of 64 dB for a 1-MHz bandwidth from 1 to 26.5 GHz. The tuner has an input third-order intercept point of −5 dBm when operating with an RF gain setting of 20 dB, and an input 1-dB compression point of −15 dBm. The local oscillator (LO) signals are well contained within the rack-mount enclosure, with the SIDC 6000 showing LO reradiation of −95 dBm or less at the RF input port.

The 50-Ù SIDC 6000 frequency downconverter/tuner is available with numerous options, including faster tuning speed and a 1-GHz L-band output. It measures 1.75 x 22 x 17 in. and weighs 20 lbs. The unit comes equipped with a female SMA input RF/microwave connector and BNC female connectors on the L-band output, IF output, and external reference input port. It consumes 100 W power from 95 to 265 VAC, but can be supplied for a 115 VAC aircraft power supply as an option. The downconverter/tuner is designed for operating temperatures from 0 to +50°C.

Elcom Technologies
11 Volvo Dr.
Rockleigh, NJ 07647
(201) 767-8030
FAX: (201) 767-1326