Testing, particularly production testing, is one of the biggest costs in IC manufacturing. Therefore, IC designers welcome anything that comes along to simplify testing and reduce its costs. That's precisely the job of an innovative vector modulator from IFR. It lets test engineers extend the life of their analog sources and preserve existing investments. IFR's new 2029 model actually combines a vector modulator with an arbitrary waveform generator (arb) and an RF level control system, which makes it well-suited for manufacturing test. Additionally, the product provides excellent RF accuracy to maximize manufacturing yields.
This product brings an economic advantage: adding the 2029 to an analog source versus replacing an analog source with a digital one saves $6000 to $13,000 per test station. Plus, displacing radio-test-set-based strategies results in even higher savings.
With the 2029 vector modulator, users can turn any analog RF signal generator into a digital signal generator (Fig. 1). They can couple it with any manufacturer's analog RF signal generator for fast conversions of manufacturing lines from testing older wireless formats to quickly testing the latest digital formats. This reduces investment costs for replacement equipment, downtime, and software. The 2029 can test 2G, 2.5G, and 3G formats ranging from 800 MHz to 2.51 GHz. Users can output digital signals in WCDMA, CDMA2000, IS-95, GSM, IS-136, and EDGE formats.
Modularity is a key feature of the instrument, eliminating the need to purchase more-expensive signal generators or air-interface-specific radio testers. This replacement cost can run as much as three times the cost of employing a 2029 with an analog signal generator. In addition, the 2029 is smaller and lighter than radio test sets, ensuring its fit in test stands where space is at a premium.
Although its excellent RF performance makes it an effective solution for testing any digital wireless product, including basestation amplifiers, the 2029 is ideal for handset testing. It was designed specifically to simplify the testing of cellular telephones in manufacturing. A priority of manufacturing test is repeatability. That's why a good solution relies on a signal source built around an arb. Because of its large storage capacity and inherent accuracy, the IFR arb is well suited to provide the precision needed for manufacturing test.
A key advantage of the 2029 is its ability to instantly switch digital formats. This instant format conversion enables testing next-generation wireless formats where wireless devices are designed and upgraded with software, not hardware. Dubbed "software radios," the new modular devices are accommodated by the 2029's flexibility. New wireless formats are simply loaded into memory and are ready to be tested with the same test equipment.
This flexibility provides manufacturers with a path to the future of advanced wireless testing. As manufacturers convert factories from older analog formats to the constantly evolving digital formats, their manufacturing lines can be converted quickly. The 2029 supports multiband, multimode phones that use the same test configuration. This means that the 2029 only requires software upgrades to keep up with the changing wireless standards.
The vector modulator uses an external analog signal generator as a fixed-level unmodulated source to provide its RF input signal. The output from the 2029 is a digitally modulated carrier.
The external generator provides a local oscillator input signal, while the internal arb generates a baseband IQ drive signal. An IQ modulator provides a vector-modulated output signal. The IQ modulator has greater than 15 MHz of analog baseband bandwidth.
The 2029 can provide a variety of modulated carriers, including IS-95, by loading suitable data files into the arb. The arb can be loaded with customer-defined waveforms. The memory can be segmented to define a number of different waveforms, typically equivalent to 15 different IS-95 signals. This allows the selected waveform to be changed without delay.
The RF-level control system allows the output to be varied over a wide range, ensuring its suitability for measuring both receiver sensitivity and overload. Excellent RF-level accuracy in the output control system and attenuator minimizes uncertainty and maximizes repeatability in manufacturing.
An RF combiner is supplied as an option so that other signals can be combined with the 2029 output, or used to connect measuring devices, like power meters and spectrum analyzers. The 2029 has no user interface and is designed for operation via GPIB. An RS-232 port is implemented for firmware and software upgrades.
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