High-Precision Sub-Nyquist Sampling System Based on Modulated Wideband Converter for Communication Device Testing

Abstract

This paper proposes a new method of constructing a compensation filter for the modulated wideband converter (MWC) system. The proposed method can be directly used in the MWC circuit without disconnecting any components. Furthermore, the non-ideal transfer characteristics of the real mixer output and the real ADC input are taken into account in the proposed compensation filter. The proposed method can be utilized in the advanced MWC that enables more flexibility in the design parameters of the MWC. This paper also demonstrates the reconstruction of the Bluetooth signal as a practical example for the evaluation of the reconstruction performance. The MWC successfully reconstructs the time-domain waveform of the signal based on the proposed compensation filter. Even in the case that the total effective number of channels in MWC is small as close to the necessary condition of the MWC, the error vector magnitude (EVM) was still under 1%, which is acceptable for Bluetooth device testing applications.