Attenuation is critical to signal processing in many systems, whether they are for communications, testing, surveillance or other functions. Mini-Circuits made some noise earlier this year with its YAT-Series miniature fixed attenuators, which allow designers to “set and forget” an amplitude level. The firm is also offering its RUDAT-6000 line of digital step attenuations when somewhat more level control is needed. Available in versions with maximum attenuation of 30, 60, and 90 dB in 0.5-dB steps from DC to 6 GHz, the RUDAT-6000 digital step attenuators can be controlled by means of Universal Serial Bus (USB) or RS-232 computer interface. They are supplied with code for programmers and control software that simplifies installation with 32- and 64-b operating systems.


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The product family includes models RUDAT-6000-30 (with 0 to 30 dB attenuation), RUDAT-6000-60 (with 0 to 60 dB attenuation), and RUDAT-6000-90 (with 0 to 90 dB attenuation). All boast 0.5-dB resolution and a frequency range of 1 to 6000 MHz. For example, model RUDAT-6000-30 (see figure) achieves ±0.75 dB typical attenuation accuracy across the operating frequency range for attenuation settings from 0.25 to 30.0 dB. It maintains low insertion loss with frequency, only 1.8 dB from 1 to 3000 MHz, and 3.0 dB or less from 3000 to 6000 MHz when the attenuation is set to 0 dB.

Model RUDAT-6000-90 is a precise step attenuator with attenuation range from 0 to 90 dB in 0.25-dB steps for use from 1 to 6000 MHz.

The attenuator is designed for a reliable impedance match in 50-Ω, high-frequency systems, with typical VSWR of 1.15:1 for attenuation of 0 to 20 dB from 1 to 500 MHz, and 1.05:1 for attenuation from 20 to 30 dB from 1 to 500 MHz. The typical VSWR is 1.25:1 for attenuation settings from 0 to 30 dB from 500 to 4000 MHz, and 1.65:1 or less for attenuation settings from 0 to 30 dB from 4000 to 6000 MHz. The attenuator provides an input third-order-intercept (IP3) point of typically +50 dBm for a 0-dB attenuation setting from 1 to 6000 MHz. As with the higher-attenuation models, the RUDAT-6000-30 features typical switching speed of only 650 ns from one attenuation setting to the next, not considering any computer programming delays (which depend on the particular control computer). The digital attenuator draws 60 mA typical current from a +5-VDC voltage supply on its USB port.

The two higher-attenuation models also deliver high attenuation accuracy from 1 to 6000 MHz, with low VSWR, fast 650-ns attenuation switching speed, high IP3 (+50 dBm), and low insertion loss. Across the 1-to-6000-MHz frequency range, model RUDAT-6000-60 maintains attenuation accuracy of ±0.25 dB for attenuation settings of 0.25 to 10.00 dB, ±0.65 dB accuracy for attenuation from 10.25 to 20.00 dB, and ±1.05 dB accuracy for attenuation from 20.25 to 60.00 dB. Model RUDAT-6000-90 achieves attenuation accuracy of ±0.30 dB for attenuation settings of 0.25 to 10.00 dB, ±0.85 dB for attenuation from 10.25 to 20.00 dB, ±1.10 dB for attenuation from 20.25 to 60.00 dB, and ±1.70 dB for attenuation from 60.25 to 90.00 dB, all for 1 to 6000 MHz.

All three digital step attenuators measure 2.20 x 3.20 x 0.80 in. in a rugged, shielded-metal case with SMA female input and output connectors, 9-pin female D-sub RS-232 port, and USB Type-B power and control port. Each attenuator is supplied with graphical-user-interface (GUI) control software and API objects for programmers, supplied on a compact disc (CD) with programming instructions for Windows® and Linux® operating systems. The step attenuators are also packaged with a 2.7-ft. USB cable, a 6-ft. D-Sub-9 male/female cable, and a power adapter with USB A female connector. With their speed and accuracy, these step attenuators should find their way into more than a few measurement and communications systems, wherever precise level control is needed through 6 GHz.

Mini-Circuits, Inc., P.O. Box 350166, Brooklyn, NY 11235-0003; (718) 934-4500, FAX: (718) 332-4661, www.minicircuits.com.