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Author: search.filters.author.Boonjun, Surapol

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    Velocity detection by ultrasonic doppler based on multi-time technique analysis
    (2019-07-01)
    Sudtana, Sukkan
    ;
    Prompak, Kriangsak
    ;
    Suphramit, Suphawadee
    ;
    Sisuk, Noppadon
    ;
    Boonjun, Surapol
    Experimental result of velocity measuring technique, namely, The ultrasonic Doppler, the technique employs a phase shift oscillator to be combination of signals for mixer replacement and tracks the Doppler frequency, is reported. The received ultrasonic signal was fed to the phase shift oscillator that generate 40.7 kHz of natural frequency as same as transmitted frequency. An output response of received ultrasonic present evidently in Doppler frequency which is proportional to velocity of object. Additionally, The great advantage of the multi-time technique could be used in order to predict its behavior. Measurement results verify the efficacy and agree well with analysis.
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    Distance Measurement Technique Using Phase Difference of Two Reflected Ultrasonic Frequencies
    (2018-09-11)
    Chongchamsai, Munchuphon
    ;
    Sinchai, Sakkarin
    ;
    Wardkein, Paramote
    ;
    Boonjun, Surapol
    This paper proposes a simple method of distance measurement utilizing phase difference of two reflected ultrasonic frequencies. To obtain the phase difference, an alternating signal which contains two sinusoidal signals having different frequencies is fed to an ultrasonic transmitter. When the transmitted signal is reflected and received by the ultrasonic receiver, the received signal is first squared. Then, a time shift property of Fourier transform is applied to the squared signal to acquire the phase difference. The phase difference is converted to a time-of-flight (TOF) value and turned to the distance. To experiment the proposed technique, a DSP TMS620C6713 board is employed to generate the alternating signal as well as to receive the reflected signal, and to process the received signal. In the experiment, two sinusoidal signals having frequencies of 39.85 kHz and 40.6 kHz are used. The results show that the obtained distance by the presented approach has fairly low error only 0.15 centimeters compared to the actual distance.