A Modulated Wideband Converter Calibration Technique Based on a Single Measurement of a White Noise Signal with Advanced Resynchronization Preprocessing

Abstract

The Modulated Wideband Converter (MWC) is a blind sub-Nyquist sampling system used especially to monitor wideband spectrum. This system can be realized by existing analog components. From a theoretical point of view, all analog components are assumed ideal. However, this hypothesis is false in practice. Indeed, some imperfections are introduced by analog components such as nonlinearities of mixers, phase/attenuation/selectivity of low-pass filters and desynchronization between modulating waveforms. Consequently, it is necessary to correctly estimate the sensing matrix to ensure correct spectrum reconstruction performance. Conventional calibration methods are based on the measurements of different single tones. However, these approaches need to record several measurements with single-tone inputs. To avoid this problem, this paper presents a new hardware calibration method of MWC by using a single measurement of a white noise signal for radio frequency spectrum monitoring. A preprocessing method is performed to resynchronize input, output and modulating waveforms signals with each other. Our hardware calibration method is applied to our prototype of Compressed Sensing (CS) scheme in order to estimate the corrected sensing matrix. To prove the efficiency of our hardware calibration, reconstruction performances were evaluated with respect to the probability of correct reconstruction and false alarm criteria. These results are compared with those obtained with the theoretical MWC scheme, with our prototype without calibration and with reference calibration.

A Modulated Wideband Converter Model Based On Linear Algebra and its Application to Fast Calibration

“…100) leads to very poor results [13]. In a previous paper [15], we proposed an approach which uses a single wideband signal for calibration, contrary to previous approaches which required successive injections of sinusoids in the system. In that paper we presented spectrum reconstruction performances and examples of spectrum reconstruction obtained with our calibration method.…”

“…Some practical implementations of compressed sensing systems have been already proposed [12][13][14]. To design a prototype of compressed sensing based on MWC scheme, we designed an analog board with discrete components [15]. Some authors have already addressed the design of MWC system and a non-exhaustive list of references is given here [11,13,[16][17][18][19].…”

“…While this procedure is efficient, it can be time consuming because the number of columns to estimate is usually at least a few dozens. That is why a few authors [24,25], including us [15], have recently proposed alternative calibration algorithms requiring only one input signal.…”

“…For our experiments on real-world data, we designed a 4-channels MWC analog board (Fig. 2) which was described in more details in a previous paper [15]. The scramblers are sampled at F nyq = 1GHz and their length is L = 96.…”

A Chaotic Compressive Sensing Based Data Transmission Method for Sensors within BBNs

“…The WBAN sensors embedded in human bodies can gather a wide range of vital signs, such as heart rates, blood pressures, electroencephalograms (EEGs), electrocardiograms (ECGs), and so forth [ 5 ], and some compressive sensing based methods have already been proposed to deal with such signals [ 6 , 7 ]. The WBAN sensors send data they collect to monitoring centers, and thus distant diagnosis could be carried out and proper solutions may be proposed based on the data received.…”