Search

International standard bodies have specified an instrument capable of detecting and assessing the severity of lighting flicker, which is called a flickermeter. However, a deficiency with regard to flicker caused by high-frequency interharmonics has been reported in the recent literature. In this paper, another deficiency of the International Electrotechnical Commission (IEC) flickermeter with regard to low-frequency interharmonics, whose frequencies are below the difference between the fundamental frequency and the cutoff frequency of a bandpass filter of the IEC standard flickermeter, will be discussed and illustrated based on analysis and numerical experiments. A new approach based on down-up sampling in the discrete-time sample domain is also proposed to address the flicker-detection problem associated with interharmonics. We demonstrate the efficacy of the proposed method by a comparison with the current flickermeter standard in the presence of interharmonics. [ABSTRACT FROM AUTHOR]

The influence of disturbing noise and nonlinear distortions on frequency response function measurements using periodic excitations has been studied in detail in the literature. A variance analysis method has been developed that allows one to detect and quantify the nonlinear distortions and the disturbing noise. In this paper, the variance analysis is generalized to detect and quantify the following nonstationary disturbances: 1) nonsynchronous periodic signals, for example, the 50 Hz mains and its harmonics, and 2) nonstationary behavior of the device under test, for example, phase or frequency modulation. [ABSTRACT FROM AUTHOR]

Quality of high-voltage (HV) impulse measurements requires adequate dynamic performance of measuring systems (MS) with respect to the waveforms to be measured. Qualification of MSs for various impulses is a prerequisite for repeatability and reproducibility of HV testing results. Alternative qualification procedures are considered with respect to the standard full lighting impulse including evaluation of significance of its frequency components. Duality of step responses and amplitude-frequency responses is described in detailed examples. Special attention is paid to creeping, encountered with some converting devices. Variations of MS response parameters can lead to improper conclusions when only conventional examination of the dynamic behavior is used. Evaluation of the response parameters is an unnecessary step, which brings additional errors to the HV measurements. The paper is pointing out advantages and practical achievements of the frequency-domain qualification of dynamic properties based on the step response data obtained both experimentally and analytically. Measurement errors of the impulse peak value and time parameters have been evaluated via fast Fourier transform (FFT), convolution, and inverse discrete Fourier transform (IFFT) for a commercial divider. Direct determination of the HV impulse measurement range, no need for any additional parameters, and illustrative graphical presentation of results are the main advantages of this approach. Limitations of different qualification approaches are discussed. [ABSTRACT FROM AUTHOR]

We present a new method of performing high-resolution path delay testing on designs targeted to field- programmable gate arrays. Our built-in self-test (BIST) architecture uses an on-chip delay line element to set the launch time of each test pattern generator to its optimum point for stressing paths in the routed chip. The rising and falling edges of each test pattern are controllable with high precision, and consequently, our test architecture catches very small timing faults that exist in the path. For example, on Xilinx Virtex-4, we catch defects as small as 78 ps using the IDELAY delay line circuit that is available on that device. Our approach was validated on Virtex-4, and the same method can be applied to any device that supports on-chip delay lines that are adjustable at runtime. Furthermore, our architecture simultaneously tests multiple paths to reduce the overall test time. [ABSTRACT FROM AUTHOR]