In the early rollout of 2.5G and 3G cellular networks, the biggest surprise has been the critical importance of signal characterization, analysis, and testing across multiple domains. Tektronix's newly released family of WCA200A Wireless Communication Analyzers meets all of these requirements for both the wireless designer and system tester (see figure).
Intended for use in both production and research-and-development (R&D) test environments, the WCA200A series consists of the 3-GHz WCA230A and the 8-GHz WCA280A Wireless Communication Analyzers. The WCA-230A analyzer is optimized for production test applications, while the WCA280A is better suited for the research-and-development designs of wireless components and devices. By combining frequency-domain and signal-modulation analysis capabilities, the two WCA200A systems give engineers a compact platform for characterizing, troubleshooting, and verifying wireless devices.
Multi-domain analysis is one of the key characteristics of the WCA200A series. This feature allows both designers and testers to perform simultaneous measurements in the frequency, time, code, and modulation domains. Having multi-domain analysis capability in one platform alleviates the need for multiple measurement systems. It also guarantees that results will correlate between different domains, thereby providing accurate comparisons. Users can display a signal in all four domains on the screen (only three at any one time). They can then compare the signal's performance across domains.
For spectral analysis, the instrument offers a wide frequency coverage: DC to 20 MHz (baseband), 15 MHz to 3 GHz, or 8 GHz (depending on the model). The reference-level amplitude-setting range extends from −50 dBm to +30 dBm with adjustments in 1-, 2-, and 10-dB steps. Frequency response at 20ºC to 30ºC (RF attenuation of 10 dB) is ±0.5 dB (baseband) and ±1.2 dB (RF/RF1).
The series' spectral-analysis portion has a dynamic range that offers a −73-dBc third-order intermodulation distortion figure. Its reference level is +5 dBm. It also flaunts a radio-frequency attenuation of 20 dB and total signal power of −7 dBm. The displayed average noise level is −150 dBm/Hz at 2 GHz.
In order to capture the high data rates found in 2.5G and 3G wireless systems, the WCA200A series provides an acquisition memory size of 64 MB (standard). That memory size can be easily expanded to 256 MB. This extended memory enables 10 sec. of a Wideband Code Division Multiple Access (WCDMA) signal to be captured. It therefore ensures that all necessary information is available for a complete analysis.
For general signal demodulation, both instruments cover BPSK to 256QAM. They even boast selectable filters that allow the analysis of non-standard signals. In total, both instruments cover all necessary formats: BPSK, QPSK, ¼/4 Shift DQPSK, 8PSK, 16QAM, 64QAM, 256QAM, GMSK, and GFSK. The maximum symbol rate is 12.8 MSamples/s. Complex error-vector-magnitude (EVM) measurement can be performed while modulating these digital signals. In addition, co-diagram capabilities provide a simple graphical means of analyzing code power versus time.
Perhaps one of the most useful features of the series is its frequency mask trigger. To capture single or multiple RF signals, the designer or tester can trigger off any known or unknown signal in the frequency domain. This trigger is even effective in the presence of signals that would be missed by traditional spectrum and vector analyzers. In other words, using the frequency mask trigger allows the WCA200A series to capture and analyze all of the known and random signals in a variety of domains.
Both WCA200A series analyzers also boast impressive adjacent-channel-leakage-ratio (ACLR) measurement speeds. These features add to the standard one-button measurements that are commonly found in vector-signal analyzers. Thanks to the analyzers' analysis and triggering capabilities, developers can further improve their view by capturing random spurious signals. They can then analyze them in multiple domains without having to make multiple measurements.
The WCA200A Series—consisting of the 3-GHz WCA230A and the 8-GHz WCA280A analyzers—is now available for order with an eight-week delivery time. Pricing starts at $27,990.
14200 SW Karl Braun Dr., P.O. Box 500, Beaverton, OR 97077; (800) 835-9433, www.tektronix.com.