Paolo Carbone

Effect of additive dither on the resolution of ideal quantizers

The effect of adding dither to a given signal before its quantization is investigated. To this aim the relationship between the statistical description of the dither and the mean value of the quantization error and of the quantizer output is derived. The presented results allow the determination of the resolution limits that can be achieved by low-pass filtering a set of quantized samples of a slowly varying dithered signal. Discrete, uniform, sinusoidal, and Gaussian dithering are analyzed, thus providing a quantitative basis for choosing the most appropriate dither signal for a given application. >

A rigorous error analysis of D/A conversion with dynamic element matching

A known approach to reducing harmonic distortion in D/A converters involves a technique called dynamic element matching, The idea is not to reduce the power of the overall conversion error but rather to give it a random, noise-like structure. By reducing the correlation among successive samples of the conversion error, harmonic distortion is reduced. This paper presents the first rigorous and quantitative theoretical analysis of the conversion error introduced by an important type of D/A converter with dynamic element matching, In addition to supporting previously published experimental results that indicate the conversion error consists of white noise instead of harmonic distortion, the analysis provides an expression for the power of the white noise in terms of the power of the input sequence and the component matching errors. A yield estimation technique based on the expression is presented that can be used to estimate how the power of the white noise varies across different copies of the same D/A converter circuit for any given component matching error statistics.

Detection of Anomalies in the Behavior of Atomic Clocks

In this paper, the problem of identifying variations in the nature of atomic clock noise is addressed. Two methods are proposed. One method is based on a generalized likelihood ratio test (GLRT), and the other is based on the dynamic Allan variance (DAVAR), which is a representation of the instantaneous clock stability that is able to point out possible nonstationary behaviors. Both methods efficiently track variations in the experimental clock data and, thus, appear as suitable tools for the detection of atomic clock anomalies

Windows for ADC dynamic testing via frequency-domain analysis

In this paper, the frequency-domain dynamic test of analog-to-digital converters (ADCs) is considered under the assumption of noncoherent sinewave sampling. A procedure is described which is based on the windowed discrete Fourier transform (WDFT), optimized for the achievement of high estimation accuracy. With this aim, the class of windows belonging to the set of discrete prolate spheroidal sequences is adopted for the reduction of the effects of spectral leakage. Practical suggestions are given for a straightforward applicability of derived results and for an efficient estimation of ADC spectral parameters. Finally, experimental results are presented in order to validate the proposed testing approach.

Noise sensitivity of the ADC histogram test

In the paper, the authors consider the performance of histogram-based analog to digital converter (ADC) testing under the assumption of input-equivalent wideband noise, which models either noise sources inside the device or unwanted disturbances corrupting the stimulus signal employed for carrying out the test. Theoretical relationships are presented which allow the design of the test parameters needed to meet a given test accuracy. Moreover, it is shown, that the histogram test is effective in providing information on the deterministic behavior of the tested device and that it can be made insensitive to the effects of input-equivalent noise. Finally, the obtained results are employed to determine the test performance in estimating the device effective number of bits, and simulations results are provided which validate the theoretical derivations.

A 5.6-GHz UWB Position Measurement System

This paper describes the design and realization of a 5.6-GHz ultrawide-bandwidth-based position measurement system. The system was entirely made using off-the-shelf components and achieves centimeter-level accuracy in an indoor environment. It is based on asynchronous modulated pulse round-trip time measurements. Both system level and realization details are described along with experimental results including estimates of measurement uncertainties.

Characterization and Modeling of an Experimental UWB Pulse-Based Distance Measurement System

This paper presents a distance-measuring system based on the accurate round-trip time-of-flight measurement of single ultrawideband pulses propagating between two transceiver devices. The architectures of two realized devices, which are referred to as the master and the slave, are described. The master device implements the time-interval measuring function by means of a time-to-digital converter (TDC) integrated circuit, whereas the slave acts as a pulse repeater. Both devices are designed for low-cost realization and low-power operations. Furthermore, two pulse-detection modules are described based on signal-threshold and energy detection, respectively. This paper also presents and discusses some experimental results that are obtained from the system prototype. Finally, some numerical simulation results, which provide an explanation for the nonidealities in the observed distance-measuring behavior of the system, are shown.

Frequency-domain based least-squares estimation of multifrequency signal parameters

This paper proposes a frequency-based least squares algorithm applied to the estimation of multifrequency signal parameters. It is based on the processing of the joint information carried by nearby frequency components of Fourier-transformed data. Theoretical and simulated analysis are carried out on the algorithm accuracy while its performance is compared to the corresponding Cramer-Rao lower bound.

Dither signal effects on the resolution of nonlinear quantizers

The consequences of dithering on nonlinear quantizers are analyzed. A model of the nonlinear quantizer is considered, and a model of the same quantizer with dither is proposed. The proposed model permits the description of both monotonic and nonmonotonic nonlinear quantizer characteristics. By means of this approach, relationships are given for the total quantization error in the case of discrete binary, uniform, and Gaussian dither signals. >

A survey on time interval measurement techniques and testing methods

The most frequently utilized techniques for precise time interval measurements are discussed. By analyzing the characteristics of both published architectures and commercial Time-to-Digital Converters (TDCs), the most significant testing methods are also considered. Related performance parameters, useful for calibrating such devices and compensating any deviations from the expected behavior, are also identified. Since full standardization activities in this field have not been carried out yet, the proposed results may reduce terminology and definition ambiguities, allowing an easier comparison between different TDC architectures. To this aim, an overall Figure of Merit is also introduced and evaluated for several published TDCs.