Floating Point Analog-to-Digital Converters (FP-ADC’s) were developed and used to quantize large dynamic range signals in applications where large signals need not be encoded with a precision greater than that required for small signals. Comparing floating-point with uniform quantization, it was shown that FP-ADC requires much smaller silicon area for the same dynamic range, but at the cost of doubling the conversion time. To improve the resolution and speed of conversion of such an FP-ADC, a higher precision predictive floatingpoint architecture was conceived (PFP-ADC). The PFPADC consists...
SNR is a characteristic of analog-to-digital (A/D) conversion. One of its applications is the valuation of the “effect” of the change of the resolution of A/D conversion. SNR may be improved by modifying the process of discretization in terms of time (sampling) and value (quantization). The present article discusses the equality of these two types of modification from the point of view of the criterion of SNR.
External correction of analog-to-digital converters is considered. First, a dynamic correction scheme is proposed to comprise bit-masking. Next, a framework for analyzing the effects of bit-reduced table indexing is derived. This framework is finally applied in an optimization problem for bit allocation in the bit mask of the introduced correction scheme. Both the dynamic correction method and the optimization problem are exemplified with experimental AD data. The results indicate that the considered correction scheme is superior to static schemes, and that the choice of bit mask is crucial,...
There is no noise-free place on Earth. Most of noisy effects are undesirable and unwelcome, especially in measuring technology. However, there are some measuring methods and algorithms using noise for quality enhancement. These processes are usually called dithering. Basic ideas of these methods were partially assumed from audio and video signal processing many years ago. The field of dithering technologies in measurement became large in recent years.
The paper presents results of ADC testing systems comparison between Laboratoire de microélectronique IXL, University Bordeaux and ADCM&T Laboratory, Dept. of Measurement of FEE CTU, Prague. The comparison was performed using transportable reference AD device designed and developed in FEE CTU.
Effects of the windowing process, widely investigated by the scientific literature for narrow–band components embedded in white noise, is not sufficiently detailed when signals are corrupted by colored noise. Such a phenomenon can heavily affect the spectral parameters estimation of the noisy signal. In this paper effects of the windowing on the output of analog–to–digital converters with ΔΣ topology, which present a spectrally shaped quantization noise, is analyzed. In particular, the spectral leakage of both narrow– and wide– band components is investigated and a criterion for choosing the...
Improvement of Analog-to-Digital Converters testing method that is suitable for testing of high-resolution AD converters (e.g. Σ-Δ or dither-based) or on the contrary ultra high-speed AD converters is presented. The method is based on the histogram test driven by stochastic signal with defined probability density function. By repeating of the test for different settings of band-pass filter that is inserted to the input testing signal path it is possible to obtain an estimation of frequency dependency of effective number of bits. The results have to be recalculated to equivalent band-pass...
In this paper a new procedure to perform four parameters sine fitting is presented in a closed form, ready for standardization. This new procedure grants convergence of the algorithm, even in those cases where the traditional techniques tend to converge to local minimums of the error function. This new procedure can also be used to compute the initial values for the traditional four parameters sine fitting algorithm if very high accuracy is required. In such case convergence of the traditional algorithm is also assured.
The Analog to digital converter (ADC) has been widely used in all kinds of modern electronic instruments, so it is desirable to find out the relationship between various errors and the performance of ADC and improve the performance with a low cost operation. This paper studies and tries to quantify the relationship between the differential non-linearity (DNL) error, the integral non-linearity (INL) error and the signal to noise ratio (SNR) performance of an ADC, and investigates various methods to reduce the effect of these errors to increase the SNR. Major results are obtained by computer...
This paper describes the design and application of a 'noise-separation' test system that uses in-system programmable logic devices and a digital signal processor. This offers a low cost approach to multi-tone testing of the wide-bandwidth linearity of both ADC and DAC systems. As the test signal bandwidth is software configurable and uses 1 bit D-A converters it can be applied to a much wider range of applications than more conventional multi-tone test methods. Time-domain processing is expected to provide meaningful results for routine tests in a much shorter time than with FFT analysis.