Baseband module reduces multisite test costs

Testing transceiver and converter interfaces requires orthogonal in-phase and quadrature analog signals. Relays are used to bypass the device site and route stimulus IQ signals into digitizers. Multisite testing complicates DUT board calibration layout due to varying trace lengths, switch losses, and triggering delays of the module's IQ DACs. MIMO devices add another dimension of complexity since they require calibration of multiple channels per device. The arbitrary waveform generators and digitizer that are increasingly contained inside the baseband module could be used to greatly reduce DUT board calibration layout challenges. Excess amplitude and phase variations will impact DUT IQ imbalances. The result typically is a negative impact on yield but also could lead to passing failing parts. One common approach to minimizing the input signal imbalances is to carefully calibrate the two input signal paths on the DUT board as close to the DUT as possible.