Enhanced Error Vector Magnitude (EVM) Measurements for Testing WLAN Transceivers

As wireless LAN devices become more prevalent in the consumer electronics market, there is an ever increasing pressure to reduce their overall cost. The test cost of such devices is an appreciable percentage of the overall cost, which typically results from the high number of specifications, the high number of distinct test set-ups and equipment pieces that need to be used, and the high cost of each test set-up. In this paper, we investigate the versatility of EVM measurements to test the variable-envelope WLAN (wireless local area networks) receiver and transmitter characteristics. The goal is to optimize EVM test parameters (input data and test limits) and to reduce the number of specification measurements that require high test times and/or expensive test equipment. Our analysis shows that enhanced EVM measurements (optimized data sequence and limits, use of RMS, scale, and phase error vector values) in conjunction with a set of simple path measurements (input-output impedances) can provide the desired fault coverage while eliminating lengthy spectrum mask and noise figure tests