Digital techniques are proposed used to develop pink noise for power handling test of AES standard,including development of white noise sequence,optimization of pink noise filter,bandwidth and attenuation control,and peak factor control.
In this paper we've made the concise review, analysis and comparison of the main approaches for evaluation of ride comfort. It is pointed out that the ISVR way is the better and more comprehensive one, and is the most applicable to evaluation of ride comfort in the vibration environment with its high crest factor.
The microcomputer is adopted in S092 bearing vibration (abnormal sound) measuring instrument to process data. According to magnitude of vibration value, the instrument can automatically change measuring range, thus the vibration value and crest factor and pulse number are distinguished.
Aimed at that the electric system function extension is difficult and the parameters measure such as crest factor and pulse number etc can not be realized for traditional S0910 vibration measure instrument, the electric unit of vibration measure instrument has been developed by using DSP technique. And this unit is suitable on site, its function extension easy and structure of the electric circuit simple.
Results The crest factors were 2.51~3.22.The vector sum of three axes(weighted root-mean-square acceleration) of driver seat,and commander seat were(1.01±0.12) m·s~(-2),and(1.68±0.25) m·s~(-2) respectively.
Theoretical analysis and examination were made and it was showed that the present statistical parameters of time domain of bearing vibrations and STFT had some disadvantages in describing the abnormal noises.
The Peak Factor for Gust Loading: A Review and Some New Proposals
In the expression of G a peak factor g is introduced to account for the maxima of the response dynamical displacement Xd(t),which is a zero mean stationary Gaussian process.
The peak factor is derived by assuming that the upcrossings of a given level are a Poisson process, which is deemed very conservative by several authors.
In the last part of the paper a nonlinear response, that of a Duffing oscillator, is considered and the problem of the peak factor for this nonlinear case is attacked by using the stochastic averaging of energy envelope.
Microhardness and abrasion wear run in dependence on the layer composition through a peak factor.
A method to determine the bandwidth of pulse signals transducers, depending on the crest factor of these signals, is described in this article.
An efficient crest factor reduction technique for wideband applications
This paper describes a new efficient crest factor reduction technique for wideband applications.
The solution involves very little user intervention (which enhances its practical usefulness) and has great benefits compared to multisine signals that minimize crest factor.
Afterprecoding the crest factor is significantly reduced and the performance, dueto introduced coding gain, improved.
In this paper we've made the concise review, analysis and comparison of the main approaches for evaluation of ride comfort. It is pointed out that the ISVR way is the better and more comprehensive one, and is the most applicable to evaluation of ride comfort in the vibration environment with its high crest factor.
The 133 drop-forgers and 95 weavers were selected as subjects for the study. The comparative results of noise parameter in the field were: The maximum linear peak (122.6-142.4dB) , variability of peak and total range of A-weighted root-mean-square level with slow time constant (LAS) in the drop-forging noise were evidently greater than those in the weaving noise; the distribution of crest factor (LAP-LAS) for the drop-forging noise was wider than that for the weaving noisei but the mean time of noise exposure...
The 133 drop-forgers and 95 weavers were selected as subjects for the study. The comparative results of noise parameter in the field were: The maximum linear peak (122.6-142.4dB) , variability of peak and total range of A-weighted root-mean-square level with slow time constant (LAS) in the drop-forging noise were evidently greater than those in the weaving noise; the distribution of crest factor (LAP-LAS) for the drop-forging noise was wider than that for the weaving noisei but the mean time of noise exposure per day (2.4h) for the drop-forger was obviously shorter than that for the weaver. According to the comparative results of the measured and potential medians of noise-induced permanent threshold shift (N0.50) at 4kHz as well as the measured N0.50 between the drop-forgers and the weavers, there were no significant differences. Moreover, the rank correlation between the different noise dose of cumulative exposure and N0.50 at 4kHz for the drop-forgers was significant. It seems that the hearing loss of workers induced by the drop-forging noise is primarily consistent with the principle of the equal energy hypothesis.
This paper introduces the fast freqency response testing method using prime number-multi-freqency-signal, which is used in a receiver comprehensive test instrument.Testing is made fast by using Multi-freqency-signal. Test error, which is caused by nonliearity, is minimized by using prime-number-multi-freqency-signal. The peak factor of the multifreqency signal is minimized by using TFDSA(Time-Freqency Domain Swaping algorithm)