Click here for the enhanced PDF version of this article

As WiMAX trials proliferate and semiconductor suppliers unveil new lines of chipsets, test equipment makers are readying solutions for the emerging measurement needs of next-generation RF communications systems. In keeping with its mantra of speed and simplicity, Keithley Instruments has developed an RF test system to tackle the complexities of 4 × 4 multiple-input, multiple-output (MIMO) antenna designs. Primary drivers for MIMO architecture is higher data throughput rates without the need for additional bandwidth.

For that, the company has developed a MIMO synchronization unit 2895, and bundled it with a new line of vector signal generators (VSG) 2920, vector signal analyzer (VSA) 2820, and MIMO signal analysis software. By allowing for tight multi-unit synchronization with these high-performance measurement instruments, the new RF test system can support MIMO measurements on demanding signals such as 802.11n 40 MHz WLAN MIMO and 802.16e Wave 2 mobile WiMAX, stated Walter Strickler, Keithley's worldwide business development manager.

The tight synchronization of signals and low sampler and RF carrier phase jitter featured in the MIMO RF test solution allow for highly accurate and repeatable measurements that ensure high product quality and high production yields, added Strickler. In addition, models 2820 and 2920 can be set up for any permutation of MIMO system including 2 × 2, 3 × 2 and 4 × 4. “These dual-purpose instruments can be used as stand-alone instruments or as part of a 4 × 4 MIMO test system, so users don't need to dedicate individual signal analyzer or signal generator units to a task,” noted Strickler.

In summary, the RF test system offers support for 4 × 4 MIMO applications with ±1 ns signal sampler synchronization, less than 1 ns peak-to-peak signal sampler jitter and less than 1 of peak-to-peak RF-carrier phase jitter. This yields down to -4 dB of EVM performance in the 5.8 GHz band when measuring the demanding 802.11n 40 MHz WLAN MIMO signal.

The RF VSG's, model 2920, frequency range has been extended to 6 GHz. It is available in two configurations with maximum frequencies of 4 GHz or 6 GHz and can generate signals as low as 10 MHz. An optional 80 MHz arbitrary waveform generator bandwidth with 100 Msamples of waveform memory gives users the capability of testing an array of commercial communications signals, including GSM, EDGE, W-CDMA, cdma2000, SISO WLAN, and the 802.11n 40 MHz WLAN MIMO signal. Likewise, the model 2820 VSA comes with 40 MHz of bandwidth as standard in a 4 GHz or 6 GHz configuration. Architected to be highly versatile, it can test a range of signals, including GSM, EDGE, W-CDMA (uplink/downlink), and cdma2000, along with a multitude of WLAN signals, including the 802.11n 40 MHz WLAN MIMO signal in MIMO and SISO configurations.

To permit up to 4 × 4 MIMO test synchronization, the MIMO synchronization unit, model 2895, offers highly synchronized signals to the system instruments. This gives the system a highly precise and stable alignment between up to four signal analyzers and generators. It distributes common signals such as a local oscillator and common clock and precise trigger to all the instruments connected to the system and allows accurate and repeatable measurements of orthogonal frequency-division multiplexing (OFDM) MIMO signals. While the PC-based MIMO signal analysis software, model 280111, facilitates either single-channel or multichannel analysis of 802.11x signals. This fast and powerful software tool features an extensive measurement suite for analyzing all 802.11x signals and is capable of supporting 4 × 4 MIMO channel configurations, according to Keithley.

While model 2820 RF VSA starts at $22,500 (4 GHz), model 2920 RF VSG begins at $17,500 (4 GHz), and model 2895 MIMO synchronization unit is priced at $9,900. Model 280111 WLAN 802.11n MIMO signal analysis software costs $9,500.
Keithley Instruments Inc.
(800) 688-9951
www.keithley.com

RSS    Save to Del.icio.us  Digg This