An M-sequence-based baseband network analyzer using a combination of hardware and software correlator

In this contribution, an m-sequence-based system for network analysis is presented. This system is based on a new correlator concept, which combines the advantages of a hardware and a software correlator. In hardware, the multiplication of the received signal with a time lagged version of the excitation signal is performed. This enables a correlation for desired time lags resulting in a short measurement time, especially for long m-sequences. In software, integrate and dump (I&D) is performed, which enables a precise integration over one sequence length or integer multiples thereof, resulting in a high side maxima suppression. Furthermore, compared to a pure software correlator, the requirements with regard to the sample and hold stage are significantly lower. First, the fundamental properties of m-sequences and of the realized correlator are discussed. Afterwords, results with optimized measurement time and dynamic range of the system, derived from numerical simulations, are presented. Furthermore, to experimentally validate the system concept, a demonstrator has been realized. Measurement results showing the achievable dynamic range are presented.