Novel Cross-Loopback Based Test Approach for Specification Test of Multi-Band, Multi-Hardware Radios

Recent advances in radio systems engineering have enabled the design of multiple RF front ends (transmitters and receivers), each servicing specific RF communication standards across different frequency bands in a single electronic package. While the design aspects of such radios have been rigorously researched, the test aspects are still evolving. This paper proposes a novel `alternate cross-loopback testing\´ scheme for a multi-hardware radio using an `optimized\´ multi-tone test input. In this approach, the transmitter corresponding to one RF standard is used to test receivers corresponding to the same or different communication standards and operating frequency bands. The test approach is compatible with half-duplex operation of the transceiver front-ends and works with all the signal modulation and demodulation software turned "off". Cross-loopback is achieved via a broadband mixer, a programmable VCO and attenuator in the loopback path. The multi-sine tests allow accurate prediction of all transmitter and receiver specifications