Key features include MIMO channel emulation to test multiantenna functions like spatial streaming, TX and TX diversity, collaborative uplink, and multicast/broadcast under diverse RF conditions. The emulator possesses superior RF performance such as noise floor, EVM, and signal-to-noise ratio (SNR) to provide error-free conformance and performance testing from 450 MHz to 5.9 GHz.
The ACE MX’s dynamically programmable parameters include propagation delay, output power, Doppler shift with wide ranges, and many pre-programmed standard channel models (3GPP, 3GPP2, ITU, SCME). Its rapidly configurable combinations of test configurations range from 1x1 single-input single-output (SISO) to 8x4 MIMO, all of which can be unidirectional or bidirectional.
Completely self-contained, the ACE MX also features bidirectional channel emulators including circulators, attenuators, adaptive white Gaussian noise (AWGN), and selfcalibration. Finally, it uses a simple graphic interface and automation application programming interface (API) with five simple steps from power up to operation. Users can perform channel model control, scanning, fast forward, rewind, and looping.
The ACE MX provides all of the backward-compatible channel emulation features that are required for the related 2G and 3G cellular products. Handoffs or “hand downs” will be common when LTE is used. That’s because products will need to shift gears to previous technologies like WCDMA or GSM if the channel isn’t sufficient to handle LTE or if LTE just isn’t available.
MICROWAVE TESTING
As wireless components and equipment continue to move up in the spectrum, testing becomes even more challenging. But again, test companies are keeping pace. Agilent has just added some products that make aerospace, defense, and other wireless microwave equipment testing faster and easier.
For example, the PNA-X is Agilent’s non-linear vector network analyzer (NVNA). The original unit, introduced back in 2007, had an upper frequency limit of 26.5 GHz. Its latest versions offer frequency coverage limits to 13.5, 43.5, and 50 GHz. All of the PNA-X models are designed to test both passive components (transistors, cables, printed-circuit boards, filters, duplexers, and backplanes), active devices and circuits (amplifiers, mixers), ICs, modules, and other subassemblies (Fig. 4).
The PNA-X’s configurable two- or four-port analyzer offers a single-connection, multiple-measurement approach for continuous- wave (CW) and pulsed S-parameters, compression, intermodulation (IMD), and noise figure measurement. It also has two built-in signal sources with high output power (+16 dBm), low harmonics (–60 dBc), and a wide power sweep range (40 dB).
Other measurements include vector noise figure, gain compression true and differential, and nonlinear vector network analysis. The internal signal routing switches simplify the change for one test setup to another with little or no additional equipment. Internal pulse modulators and generators are included to simplify and speed up measurements.
The 13.5-GHz model is designed to meet the needs of a wide range of wireless communications products where reduced test time, number of test stations, and test cost are critical. Multiple stations are often needed to complete the testing on a product, such as a low-noise amplifier (LNA) where gain, match, distortion, and noise figure must be measured. The PNA-X can perform all of these tests with a single connection and reduce the number of test stations by as much as 75% or cost by 30%.
The 43.5- and 50-GHz models target radar, satellite, and electronic warfare (EW) applications that usually require complex test systems with multiple racks of many instruments. Because so many test functions are already built into the PNA-X, it’s possible to reduce equipment count by 50% and increase throughput by 400%. Using the NVNA, you can make S- and X-parameter measurements and then use them with Agilent’s Advanced Design System to simulate actual linear and nonlinear component behavior.
Designed to improve some aspects of microwave testing, Agilent’s PSG E8257D signal generator option 521 has a frequency range of 250 MHz to 20 GHz (Fig. 5). The big news, however, is that this generator breaks the 1-W (+30 dBm) output power barrier. This feature alone helps eliminate extra amplifiers, couplers, and detectors.
Most generators in this frequency range deliver less than +25 dBm, yet some applications require more power for proper testing, like traveling wave tube (TWT) testing and automatic-test-equipment (ATE)/ antenna test configurations. In many test setups with multiple cables, filters, switches, couplers, and so on, these interconnecting devices introduce significant attenuation that often must be compensated for with an external amplifier.
Also, the PSG E8257D’s adjustable RF output power hardware clamp can protect sensitive devices under test from excessive power exposure. It can be varied over the +15- to +33-dBm range.
Microwave testing often needs even higher power. The Giga-tronics GT-1000A linear amplifier provides up to 40 dBm (10 W) of output power from 2 to 20 GHz (Fig. 6). Some of the many applications include wireless communications, electromagnetic compatibility/electromagnetic interference (EMC/EMI), defense EW, radio-frequency IC (RFIC) and monolithic microwave IC (MMIC) testing, basestations, radar, and satellites.
The GT-1000A also makes a good ATE building block. The output power is typically 5 to 7 W in the 8- to 20-GHz range. Maximum load voltage standing-wave ratio (VSWR) is 3:1, and the harmonic distortion is less than 30 dBc typical.
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