9762 papers found
We present an analysis of the quantization error for generalized (nonuniform and/or nonmonotonic) quantizers. The mean value and mean squared value of the quantization error and the quantized output are derived in terms of the observed signals. The results can be used to identify basic parameters of ADC converters. The results can be utilized in the reference models used in the ADC test methods recommended by the IEEE.
In measurement system design, uncertainty is usually reduced by a cost increase: more accurate components are selected and narrower variations to influence parameters are imposed. In this paper, an alternative cost-saving approach is proposed: suitable values of design parameters capable of minimizing the measurement uncertainty due both to component’s uncertainty and to influence parameters are identified without any loss in other metrological performances. With this aim, a general method based on statistical parameter design is proposed. The method effectiveness is highlighted by an...
Parameters estimation of a data acquisition system can be performed by using several estimation algorithms. The choice of the most appropriate test method is not straightforward, but it depends on both the type of the converter under test and on the parameters to be measured. Moreover, various test methods and algorithms may present different sensitivities to noise and system parameter’s variations, thus resulting in diverse estimation accuracies. In this paper, the number of effective bits of a commercial 16-bit acquisition system has been evaluated by using a remotely controlled...
This paper analyzes the effect of analog-to-digital bandpass Sigma-Delta conversion on the performance of Orthogonal Frequency Division Multiplexing (OFDM) systems. A brief description of both OFDM systems and the related simulation model is given. The nonlinear effects of quantization overload on overall OFDM performance are evaluated in terms of quantization noise power and bit error rate. It is shown how minimizing quantization noise power can lead to suboptimal results. Moreover a set of minimum performance requirements for Sigma-Delta converters is established.
A virtual instrument to perform conducted emission measurement on power drive systems has been designed and has been implemented by standard digital instrumentation, in conformity with CISPR Standard Rules for this kind of measurements. Experimental tests have been carried out to compare the emission level measured by the proposed instrument with respect a compliance CISPR Receiver.
In the process of data acquisition the analogic gain is usually determined by the peak value of the input signal. For all samples the quantization error is theoretically less than 1/2 LSB. However for samples having small value, the relative error due to the quantization is high, and it goes higher with the decreasing of the sample value. The relative measuring error can be reduced by dynamically setting the proper gain. This is usually achieved with a supplementary hardware arrangement. The solution proposed in this paper consists in a numeric algorithm, developed in LabView, which replaces...
This paper describes the modeling of A/D converters in HDL languages such as Verilog [1] and VHDL[2]. It starts with an introduction about the importance of hardware modeling to support the flow of modern integrated circuit design, followed by the presentations of two case studies. The first case study is an A/D converter with successive approximations architecture [3][4][5]. The functional model was written in VHDL. The second case study is an A/D converter with pipelined architecture [3][4][6], whose functional model was written in Verilog.
The paper deals with jitter measurement in PDH/SDH-based telecommunication networks. The attention is mostly paid to the accuracy assured by any PDH/SDH analyser compliant the ITU-T recommendations, which seems to be unsatisfying for both designers and manufacturers. Trying to give an answer to this problem, a digital signal-processing method was already proposed by the authors; it avoids the use of a timing recovery circuitry, which strongly degrades the aforementioned accuracy. The method is here optimised with the aim both of further enhancing the accuracy on jitter estimates and testing,...
The analog to digital front-end of high speed acquisition systems requires fast A/D conversion and fast filtering. These performances are difficult to obtain if the acquisition calls for large wordlength. Great design and implementation efforts are needed in order to match the required throughput. The Residue Number System (RNS) appears to be very attractive, but it requires an expensive conversion from binary to RNS representation. A possible solution is the direct conversion from analog to RNS. In this paper a Residue Number System approach to the realization of a high speed front-end for...
We present our analysis of the nose-to-nose (ntn) method for use as an accurate sampler calibration method. The variations in the measurement of the sampler impulse response using the ntn method are described and the assertion that the kick-out pulse is identical to the sampler impulse response is assessed. Temperature effects on the ntn method are also examined. Finally, the effect of uncertainties in the ntn calibration method on the uncertainties in reported pulse parameters is examined.