Model calibration of non-ideal lowpass filter in modulated wideband converter for compressive sampling

Abstract

Purpose

The purpose of this paper is to present a model calibration technique for modulated wideband converter (MWC) with non-ideal lowpass filter. Without making any change to the system architecture, at the cost of a moderate oversampling, the calibrated system can perform as the system with ideal lowpass filter.

Design/methodology/approach

A known test sparse signal is used to approximate the finite impulse response (FIR) of the practical non-ideal lowpass filter. Based on the approximated FIR filter, a digital compensation filter is designed to calibrate the practical filter. The calibrated filter can meet the perfect reconstruction condition. The non-ideal sub-Nyquist samples are filtered by a compensation filter.

Findings

Experimental results indicate that, by calibrating the MWC with the proposed algorithm, the impaction of non-ideal lowpass filter could be avoided. The performance of signal reconstruction could be improved significantly.

Originality/value

Without making any change to the MWC architecture, the proposed algorithm can calibrated the non-ideal lowpass filter. By filtering the non-ideal sub-Nyquist samples with the designed compensation filter, the original signal could be reconstructed with high accuracy.

Citation

Zhao, Y., Wang, H. and Dai, Z. (2015), "Model calibration of non-ideal lowpass filter in modulated wideband converter for compressive sampling", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 34 No. 3, pp. 941-951. https://doi.org/10.1108/COMPEL-06-2014-0138