A new low cost phase-hit rig used in factory acceptance testing of master oscillators of digital radio systems

Reports the findings of a study recently undertaken for Continental Microwave Ltd. (Luton) concerning the feasibility of a low-cost alternative measurement technique particularly suitable for off-line factory-acceptance testing of master oscillators intended for use in digital radio systems. In particular the problem of implementing the measurement technique for a quaternary phase shift keying (QPSK) radio system operating in the high Mbit/s range is addressed. In QPSK each consecutive pair of data bits is mapped into one of four phase states. However the technique is by no means limited to only four phase states. The technique relies on injecting simultaneous and identical phase hits into the outputs of the master oscillators of a digital radio system thereby initiating a random error generation process and emulating the effects of phase noise and spectral spreading or any other imperfections on the overall bit error rate [P(e)] performance of a particular digital radio system