Offset Loopback Test For IC RF Transceivers

In this paper we develop an offset loopback test setup for integrated RF transceivers (TRx´s). Basically, addressed are architectures, which are not suitable for direct loopback test such as FDD transceivers or TDD transceivers where the transmitter (Tx) and receiver (Rx) share one frequency synthesizer (called VCO modulating TRx´s). The technique makes use of an extra mixer put on chip to compensate for the incompatibility of the Tx and Rx, i.e. to compensate for a difference between the transmit- and the receive frequency, and/or to introduce a baseband signal needed for test. We discuss the problem in terms of system-level models, which are implemented and verified in Matlabtrade