New Wideband Attenuator Simplifies Testing
By Brian Walker, JFW Industries, Inc.

The new 50P-1857 programmable attenuator from JFW Industries offers solid-state reliability and superior broadband performance. With an operating frequency range of 200 to 6000 MHz, it is ideal for today’s wideband variable attenuator requirements, including VHF/UHF, LTE and WiMAX testing applications. This 50 Ohm device has a dynamic range of 0 to 95 dB in 1 dB steps and is guaranteed monotonic across its entire bandwidth. It is rated to handle up to +20 dBm of RF input power with minimal compression and as high as +25 dBm without damage. The VSWR is a maximum of 2.0:1, or greater than 9.54 dB of return loss. The 50P-1857 also changes attenuation settings quickly, with an impressive 700 nanosecond switching speed. The seven-bit attenuator is controlled via seven TTL lines (TTL High turns pads On, TTL Low turns pads Off) and it requires a +5 Volt DC supply. SMA female connectors are standard on the input and output, but other connector configurations may also be available upon request.

These specifications, along with a compact and rugged package design, have instantly made the 50P-1857 the new flagship of JFW’s attenuator line and spawned several other new models based on its design. In addition to the 0-95 by 1 dB-model described above, other attenuation ranges are available. They include a 0 to 63 dB in 1 dB step version and a 0 to 31.5 dB attenuator with 0.5 dB resolution. And, for applications where it is not possible to maintain uninterrupted TTL control signals, JFW also offers a digitally latching solution.

Building on this assortment of innovative programmable attenuators, JFW Industries continues to expand its line of RF and microwave test equipment by launching a brand new family of programmable attenuator assemblies for automated testing applications. The family begins with the basic 50PA-516, a plug and play RF test solution consisting of two 50P-1857 programmable attenuators (on independent RF paths) integrated with a single Ethernet/RS-232 network interface for remote control, a front panel interface for manual control (via sixteen-button keypad with three-line display), and a universally adaptable AC power supply (100 to 240 Volts AC @ 47-63 Hz). This complete testing solution allows the user to instantly automate the variable attenuation stage of the test process, dramatically reducing total test time.

Computer control offers the user a variety of programming options, the simplest of which is through JFW’s proprietary GUI (Graphic User Interface). The onscreen display allows a user to set desired attenuation levels with the click of a mouse. Virtual slide controls for each programmable attenuator provide an interface that is almost tactile, with instant visual feedback on all effected changes.

For more complex testing applications, the 50PA-516 also supports remote control via a choice of onboard Ethernet or RS-232 interfaces. By connecting the attenuator assembly to a LAN (Local Area Network), the user can program the attenuators individually to perform intricate test protocols. Commands are sent as simple strings of ASCII commands. For example, “SA1 95” followed by a carriage return sets attenuator number one at 95 dB. To make programming easier, a complete test program is included with all JFW test systems. It is the same coding used for testing the device in the factory and can provide a framework for creating many basic RF test scripts.

For RF and microwave engineers in specific wireless communication fields, JFW goes even further by writing function commands for some of the most common testing scenarios into the system’s firmware. Originally written to speed up receiver sensitivity testing, the Fade Attenuator command automatically steps the attenuation between two dB settings over a set time interval. Our Variable Handover command makes wireless device testing even easier by increasing the attenuation on one RF path while simultaneously decreasing the attenuation on another RF path. As with the Fade command, the user determines the minimum and maximum dB values and the desired time interval of the change. This feature can be used to simulate the forced handover of a wireless device between two base stations, expediting time to market by drastically reducing the amount of time required for research and development, production testing, and software debugging.

In many cases, it is necessary to connect many different mobile devices to multiple base stations. JFW’s family of programmable RF attenuation systems has off-the-shelf models with up to eight attenuators onboard (available in both bench top or 19" rack enclosures). JFW also offers custom system designs incorporating broadband power dividers, RF switches, and other passive or active components. There are no fees for these application specific designs (no NRE). In addition, custom firmware and programming scripts are also available. Please visit our website for more information or to submit your custom request.

JFW INDUSTRIES
www.jfwindustries.com
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