The Modulated Wideband Converter (MWC) is one of the promising sub-Nyquist sampling architectures for sparse wideband signal sensing, cognitive radio applications and so on. In order to design an MWC-based RF receiver that meets a target RF specification, noise figure (NF) of the MWC has to be well-defined by its design properties. In this paper, we investigate a comprehensive explanation for NF of MWC by an analytic approach based on a proposed notation of an average noise figure (ANF) of the MWC. Consequently, the analysis is proven with simulation results in order to demonstrate its feasibility.

The Modulated Wideband Converter (MWC) is one of the promising sub-Nyquist sampling architectures for sparse wideband signal sensing applications. Its frequency support detection and the reconstruction ability is well-defined through compressed sensing theory. However, the reconstruction performance of the MWC is strictly limited by the non-ideal components in practical implementations. Previous calibration methods exploit sequential single-tone signals to estimate the actual transfer function of the MWC, which is fairly timeconsuming. We propose a new calibration method that estimates the actual sensing matrix coefficients of the MWC only with a single measurement based on a pilot multi-tone signal. The feasibility of the proposed calibration method is demonstrated in terms of normalized mean square error (NMSE) and image rejection ratio (IRR) of the reconstructed original signal.

Interleaving is one method of configuring a high-speed waveform digitizer. It is known that, in this method, using multiple A-D converters (ADC) enables sampling at a rate higher than the sampling rate of the ADC being used. Degradation of the dynamic range, however, results from such factors as phase error in the sampling clock applied to the ADC, and mismatched frequency characteristics among the individual ADCs. This paper describes a method for correcting these mismatches using a digital signal processing (DSP) technique. This method does not require any additional hardware; good correction and improved accuracy can be obtained simply by adding a little to the computing overhead.

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.

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