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RF Test Suite Makes Manual/Automated Multi-Port Tower-Mounted Amp Tests

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ChipCenter's Alex Mendelsohn says . . .

Anritsu Company Introduces Test System That Allows Engineers to See True Performance of Tower-Mounted Amplifiers TMATS Provides a Single-Connection Solution for Manufacturing Sophisticated Multi-Port Tower-Mounted Amplifiers (TMAs) Used in Emerging 3G Base Stations Seattle, Wash.--Anritsu Company introduced the ME7842B Tower-Mounted Amplifier Test System (TMATS), which dramatically simplifies testing Multi-Port TMAs by orchestrating final test measurements in under 30 seconds. TMATS, which consists of Anritsu's Scorpion Vector Network Measurement System (VNMS), flexible multi-port test set, and easy-to-use Scorpion Navigator software, dramatically simplifies the complexity of testing multi-port TMA configurations, can conduct final tests in < 30 seconds, and can easily integrate into existing test-executive environments in about a week. The flexibility of the ME7842B is in the test-set design, which allows TMAs with 2–5 ports to be thoroughly tested with a single connection. The test set's design increases manufacturing efficiency and productivity compared to alternative TMA testing methods that require multiple test stations. For added flexibility, Anritsu has designed TMATS with two auxiliary paths so the system can accommodate custom measurements like Adjacent Channel Power Ratio (ACPR) as well as future requirements. With Anritsu's Scorpion Navigator software, TMATS provides engineers with the power and simplicity to see the true performance of both current and future TMA configurations. The ME7842B provides the necessary paths for S-parameter tests that can be performed with clear pass/fail limit lines to quickly determine insertion loss, return loss, ripple, and out-of-band performance. Active measurements, such as gain, noise figure (NF), compression, harmonics, intermodulation distortion (IMD), and adjacent-channel power ratio (ACPR), can also be performed in many paths. In addition, the Navigator software does not require a significant learning curve because of the intuitive user interface for handling the different paths and measurements. This approach ensures the system can be brought on-line quickly and begin characterizing most TMA configurations in only a few hours. Complementing the flexibility is TMATS's accuracy and measurement speed. The test set performs S-parameter measurements with +0.1 dB accuracy, and has an IMD accuracy of +1 dB max. (at > -60 dBc). It can measure noise figure less than 0.5 dB and gain compression as high as +16 dBm. Depending on the test requirements, the TMA measurements can be performed in minutes, and in some cases, seconds, instead of hours. By conducting tests typically faster than other test systems, TMATS dramatically reduces the costs associated with manufacturing the variety of TMA configurations. Covering the 10 MHz to 6 GHz frequency range, TMATS handles a maximum TMA output power level of +20 dBm, and has a typical dynamic range of 80 dB. This system can provide an input power range to the TMA of 0 dBm to -85 dBm, with a typical port-power accuracy of +0.1 dB when using an optional power meter. TMATS's ability to conduct such accurate analysis on current and future TMA configurations is extremely important in light of emerging 3G applications. When installed close to the antenna, the TMA reduces system noise and improves sensitivity, which will enable installed base stations to accommodate lower power 3G signals. The accurate analysis of TMAs by TMATS will help assure the successful transmission of 3G digital mobile signals in these applications. TMATS has a starting base price in the U.S. of $91,825. Delivery is 12 weeks ARO. For more information, visit www.us.anritsu.com.

Anritsu's Model ME7842B Tower-Mounted Amplifier Test System (TMATS), with its optional power meter, AutoCal module, and a PC, can get you up and running making RF measurements that would usually require a rack full of equipment to handle. You can also add a signal generator to the suite in order to make adjacent-channel power-ratio (ACPR) tests. All testing is accomplished with a single-connector approach, conveying the specs shown in the table below. click for full-size table The basis of the system is Anritsu's existing family of MS462xx Vector Network Measurement System components. The VNMS line comprises a two-port S-parameter measurement box consisting of an RF source and an ultra linear receiver. Together, these modules let you characterize RF components over time and frequency, and measure RF power, from frequencies of 10 MHz to as high as 9 GHz, depending on options. A VNMS system can also be upgraded to handle 3- and 4-port S-parameter measurements. You can also add a number of options to a 2-, 3-, or 4-port S-parameter engine so that you can perform time-domain measurements, or get a receiver's noise figure or intermodulation distortion (IMD) characteristics so that you can see how it will "play" in a real-world site colocated with emitters. Another option is a Frequency Translating Group Delay subsystem. A word about ACPR analysis. It's now recognized as a critical measurement approach, especially when testing RF power amplifier (PA) stages. But, making ACPR tests can be tedious, and it usually means hauling out special test gear. Nonetheless, for today's cell-phone standards, ACPR testing can help characterize the distortion inherent in PAs and drivers. ACPR tests can help zero in on a transmitter that might be causing interference on another assigned channel. In the "old days" of cellular transmitters using analog modulation, such co-channel distortion could be simulated by two sine waves representing two active channels. In such tests, the third-order product of these two tones would be the frequency causing the interference in a third channel. As cellular modulation schemes have become digital and more complex, however, you can no longer use sinusoidal representations to simulate problems. That's where ACPR testing comes in. Speed Is Essential What's neat about Anritsu's system is that all of these types of measurements can be ascertained quickly, thanks to a windowed graphical user interface (GUI) in the bundled software. The press release states that Anritsu's Scorpion Navigator software lets you see the "true performance of both current and future TMA configurations." The graphical Scorpion Navigator screens are indeed straightforward, so it seems like that promise may hold true. Once calibrated, for example, window selections let you choose a desired TMA path and the necessary measurement to get started. Standard routines let you make ACPR tests as well as S-parameter measurements, and you can invoke menu-driven Pass/Fail limit lines. Green display lines indicate passes; red indicates a fail condition, a state that may require tuning of RF stages. You can also use windows to set up the ME7842B to make compression, IMD, noise figure, and harmonic checks. The system's displays show the results of the tests, and also give you hooks to pause during measurements. That way you can change parameters and alter auto-scaling values. Anritsu claims that its user interface encourages hands-on tuning rather than hands-on instrument operation, which is always a welcome condition, especially when first acquainting yourself with a new piece of complex test gear. Signal-Flow Diagrams The Scorpion Navigator executables also include a number of appealing utilities and features. One is a block-diagram graphics display that shows signal flow. It can really speed up your interaction with the ME7842B. The software also recommends set-up parameters, and can do auto-setup too. After specifying a TMA path, for example, all you need do is select the measurements and frequency range for your requirements, and then let the ME7842B's Cal Setup Wizard do the rest. Selecting a "Run Cal Now" routine, for example, lets you perform required calibration so that you can characterize a TMA with a single connection. When making S-parameter tests, the Wizard helps specify RF connector and calibration types, as well as other parameters. Automated Operation Although the wizards can ease manual operation, the ME7842B can be automated, too, and readily integrated into a test executive. Once you've made a measurement with the Scorpion Navigator, you can then quickly integrate it. An on-screen button activates a VisualBASIC (VB) module that re-creates the currently displayed measurement for automatic generation. This procedure provides a fast route to further customize your tests, using as few lines of additional code as possible. The generated VB module also uses ActiveX modules that can plug into a variety of popular test-software environments such as Excel (including any VB for Applications enabled software), HP-Vee, VBScript, and JavaScript, as well as Visual C++, and National Instrument's popular LabView, LabWindows, and Test Stand. The VB module includes all requisite code to duplicate calibration, setups, measurements, and outputs. The system's comments also let operators without programming experience to master automating TMA amplifier tests. Unfortunately, I had a great deal of difficulty getting anyone at Anritsu to discuss this new instrument. After a frustrating series of telephone calls to any number of 800 lines, I finally got a promise that someone would call me back. However, at press time, no such call was forthcoming. Let's hope that Anritsu's commitment to paying customers is better than that to the working press. You can try your luck at a variety of contacts posted on Anritsu's Web site.

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