Time filter

Source Type

Tu B.,Beijing University of Technology | Li D.S.,Beijing University of Technology | Lin E.H.,Beijing Pulimen Electronic Science and Technology Co LTD | Ji M.M.,Beijing University of Technology
Eurasip Journal on Advances in Signal Processing | Year: 2012

Wireless measure while drilling (MWD) transmits data by using mud pulse signal; the ground decoding system collects the mud pulse signal and then decodes and displays the parameters under the down-hole according to the designed encoding rules and the correct detection and recognition of the ground decoding system towards the received mud pulse signal is one kind of the key technology of MWD. This paper introduces digit of Manchester encoding that transmits data and the format of the wireless transmission of data under the down-hole and develops a set of ground decoding systems. The ground decoding algorithm uses FIR (Finite impulse response) digital filtering to make de-noising on the mud pulse signal, then adopts the related base value modulating algorithm to eliminate the pump pulse base value of the denoised mud pulse signal, finally analyzes the mud pulse signal waveform shape of the selected Manchester encoding in three bits cycles, and applies the pattern similarity recognition algorithm to the mud pulse signal recognition. The field experiment results show that the developed device can make correctly extraction and recognition for the mud pulse signal with simple and practical decoding process and meet the requirements of engineering application. © 2012 Tu et al.; licensee Springer.

Li C.-Z.,Beijing Pulimen Electronic Science and Technology Co LTD | Shao F.-Q.,Liaoning University | Kan Z.,Liaoning University
Jiliang Xuebao/Acta Metrologica Sinica | Year: 2013

The method of temperature measurement by acoustic pyrometers is based on the combination of acoustic wave and CT technique, and the accurate measurement of acoustic wave time of flight is the key link in its application. In the complex reverberation background condition, the traditional correlation algorithm could not overcome convolution interference, it may cause the multi-correlation peak values. In the application of acoustic pyrometer system, the generalized cepstrum correlation algorithm can transform the product and convolution homomorphism system to linear system by using cepstrum operation, thereby, this algorithm can separate product signals or convolution signals, filter the product and convolution interferences. The experimental result and theory proved that, compared to the traditional correlation function analytical algorithm, the new cepstrum algorithm can overcome the convolution interferences from reverberation, and sharpen peak value, thereby estimate the time delays of signals.

Tu B.,Beijing University of Technology | Li D.-S.,Beijing University of Technology | Lin E.-H.,Beijing Pulimen Electronic Science and Technology Co. | Ji M.-M.,Beijing University of Technology | Zhang J.-J.,Beijing University of Technology
Beijing Gongye Daxue Xuebao/Journal of Beijing University of Technology | Year: 2013

This paper analyzes the inclusions in the mud pulse signal noise. Correlation de-noising algorithm and moving median estimate algorithm to eliminate the mud pulse signal noise and pump base value drift were applied. Then for Manchester encode mud pulse signal characteristics, the correlation coefficient identification algorithm and local feature recognition algorithm were applied to the identification of the mud pulse signal. The experimental results show that the process of de-noising and decoding algorithm is simple and practical, high reliability, low decode error rate. All these comply with the requirements of the engineering application.

Tu B.,Beijing University of Technology | Li D.,Beijing University of Technology | Lin E.,Beijing Pulimen Electronic Science and Technology Co.
Chinese Journal of Sensors and Actuators | Year: 2012

The well-down relevant data can be observed through the mud pulse signal in MWD(Measurement While Drilling). It is core of technology to the ground decoding system to detect and recognize the mud pulse signal in MWD. However, there are all kinds of noise that exsited in the signal channel. The noise greatly affects the mud pulse identification. Firstly, this article offers a new way to analyse mud pulse signal noise based on Manchester encode. Secondly, it used NLMS(Normalizod Least Mean Square)adaptive filter algorithm to wipe the pump noise and other interferences. It can more effectively decrease the influence of pump pulse base-value. The mud pulse recognition model have been established according to the mud pulse features. The clustering algorithm have been applied to identification of the mud pulse signal. Finally, field test results showed that the clustering identification algorithm can recognize the mud pulse correctly and the decoding process is easier, higher reliability, lower code error. All these comply with the requirements of the engineering application.

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