Testing a plurality of communication devices. A plurality of signals may be received from the plurality of communication devices. The plurality of signals may include a signal from each of the plurality of communication devices, where a first subset of the plurality of signals has a different frequency than a second subset of the plurality of signals. The received signals may be combined into a combined signal. The combined signal may be downconverted to a combined signal, e.g., by mixing the combined signal with an output from at least one local oscillator. The downconverting may generate a plurality of lower frequency signals, each corresponding to one of the plurality of received signals. Testing may be performed on each of the plurality of lower frequency signals.