Normally cavities or voids included in electrical insulation are filled with gases, which have lower breakdown strength than the surrounding insulation. Under the normal working conditions of the insulation system, the voltage across the cavity may exceed the breakdown value of the filling gas and cause a breakdown in the cavity. This phenomenon is called Partial Discharge (PD). This research is focused on methods using basically detection and quantification of PD charge per the voltage pulses in charge sensitive amplifier. Two different principles of processing PD events are used - analog...
This paper deals with a novel strategy to face effectively cost and complexity issues associated with the static testing of last generation digital-to-analog converters (DACs). The proposed approach is based on a high-level model that takes advantage of the basic structural features common to most high-performance DACs, thus enabling a major reduction in the total number of input test vectors. The efficiency improvement resulting from this procedure not only decreases the overall testing time, but it also promotes the design of both inexpensive Built-In Self-Test (BIST) architectures and...
The paper reports on the investigation and simulation about the influence on the Digital Down Conversion (DDC) output signal of (i) the Σ∆ modulator, (ii) the pipelined ADC architecture and (iii) some relevant non-idealities of their model such as the sampling jitter, thermal noise and finite gain of the operational amplifier. The investigation is performed in the case that the digital filters of the DDC are in accordance with the GSM mask.
Designing leading-edge systems (e.g., communications systems) requires knowledge about the technological limits. Jitter is the limiting effect in ADCs with a digitization bandwidth between 1 MHz and 1 GHz. The effect of aperture jitter and clock jitter have been investigated previously. However, some very important aspects are still missing, in particular investigations on the spectral distribution of the jitter induced error. This gap is filled by this paper.
Internal wave with a soliton-like, large amplitudes within several kilometers, is frequently observed in the sea surface caused by tidal rectification due to sill or rough topographic changes. Internal waves can perturb current and density field, initiate bottom sediment re-suspension and mix nutrients to photic zone. Previous studies indicate that the appearance of internal wave in the Lombok Strait have been detected in SAR image data. This paper studies effect of internal wave in the Lombok Strait on distribution of chlorophyll in the surrounded areas using SeaWiFS and ERS SAR images data...
New duty-cycle–to–code conversion method is described in the Paper. It is based on the determination of average pulse width and average period during the conversion time T q . The last one is determined by the beforehand given quantization error δ and equals to the integer number of periods. Due to this, the component error by reason of non-multiplicity of conversion time T q and period T x is eliminated. The method allows to measure the duty-cycle in a wide range of frequencies of input signals. The quantization error does not depend on the frequency of converted signal f x and is...
The switching between channels when performing multi-channel data acquisition originates errors in the result of the analog to digital conversion due to the non-ideal behavior of multiplexers. Here we discuss the test methods required to quantify those errors, presenting the shortcomings of existing ones and proposing new testing procedures.
An alternative spectrum-based approach for determining the phase-plane error of an analog-to-digital converter is proposed. The method exploits a phase-plane error modeling, based on a dual-tone input stimulus and an output spectrum analysis [1]-[2]. In this way, the amount of data required by the dual-tone histogram test [3] is reduced.
In this paper an extension of a previously developed and well-proven technique for the estimate of the INL of an ADC via spectral analysis methods is presented and discussed. Until now the authors applied this technique only to estimate the static INL, but further in-depth analyses show that it can be used to measure the ADC response to a sine wave even if the dynamic nonlinearity cannot be neglected (i.e. when the frequency of the input signal is higher than a given limit). To prove the validity of the method the authors compare their results with those obtained by the a time-consuming but...
The paper deals with the measurement uncertainty evaluation of the PC-based measurement instruments, by using the effective number of bits, that is a well know parameter, usually employed to characterise the overall behaviour of an A/D converter. In order to verify if this parameter can be also used to assess the measurement uncertainty, we use an ad-hoc developed software tool. The results show that using the effective number of bits can lead to an underestimate of the uncertainties.