scholarly journals Comparison of Frequency Features of Pulse Echoes from Different Reflectors

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Anatoly B. Rinkevich ◽  
Olga V. Nemytova ◽  
Dmitry V. Perov
Keyword(s):  
Instantaneous Frequency ◽  
Piezoelectric Transducer ◽  
Wavelet Transformation ◽  
Noise Immunity ◽  
Elastic Media ◽  
Frequency Determination ◽  
Pulse Echo ◽  
Frequency Features

The analysis of interaction of ultrasonic pulses with different reflectors which are located in elastic media is carried out. A parameter which allows estimating the form of reflector is instantaneous frequency of pulse-echo. This parameter is an unsteady pulse echo characteristic. Instantaneous frequency determination algorithm is to use wavelet transformation which has increased noise immunity. It is shown that the instantaneous frequency value for a pulse echo is often shifted from a rated frequency of piezoelectric transducer. Difference between the frequencies extensively depends on the reflector form.

Ultrasonic Imaging Using the Instantaneous Frequency of Pulse-Echo Signals

1985 ◽  
pp. 487-496 ◽  
Author(s):  
D. A. Seggie ◽  
G. M. Doherty ◽  
S. Leeman ◽  
L. A. Ferrari
Keyword(s):  
Instantaneous Frequency ◽  
Ultrasonic Imaging ◽  
Pulse Echo

scholarly journals Acoustic Stimulation by Shunt-Diode Pre-Linearizer using Very High Frequency Piezoelectric Transducer for Cancer Therapeutics

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 357 ◽  
Author(s):  
Hojong Choi ◽  
Se-Woon Choe
Keyword(s):  
Cancer Cells ◽  
Cancer Cell ◽  
Piezoelectric Transducer ◽  
High Frequency ◽  
Acoustic Stimulation ◽  
Therapeutic Effects ◽  
Very High Frequency ◽  
Echo Detection ◽  
Pulse Echo ◽  
Very High

In this paper, we proposed cancer cell acoustic stimulation by shunt-diode pre-linearizer scheme using a very high frequency (≥100 MHz) piezoelectric transducer. To verify the concept of our proposed scheme, we performed pulse-echo detection, and accessed therapeutic effects of human cervical cancer cells exposed to acoustic stimulation experiments using 100 MHz focused piezoelectric transducer triggered by PA with and without the proposed shunt-diode pre-linearizer scheme. In the pulse-echo detection responses, the peak-to-peak voltage of the echo signal when using the PA with shunt-diode pre-linearizer (49.79 mV) was higher than that when using the PA alone (29.87 mV). In the experimental results, the cell densities of cancer cells on Day 4 when using no acoustic stimulation (control group), the very high-frequency piezoelectric transducer triggered by PA only and PA combined with proposed pre-linearizer schemes (1 V and 5 V DC bias voltages) showed 100%, 92.8 ± 4.2%, 84.2 ± 4.6%, and 78 ± 2.9%, respectively. Therefore, we confirmed that the shunt-diode pre-linearizer could improve the performances of the pulse signals of the PA, thus, enabling better therapeutic stimulation performances for cancer cell suppression.

Instantaneous Frequency Features for Noise Robust Speech Recognition

2019 ◽  
Author(s):  
Shekhar Nayak ◽  
Dhar B. Shashank ◽  
Saurabhchand Bhati ◽  
Koilakuntla Bramhendra ◽  
K. Sri Rama Murty
Keyword(s):  
Speech Recognition ◽  
Instantaneous Frequency ◽  
Robust Speech Recognition ◽  
Noise Robust Speech Recognition ◽  
Noise Robust ◽  
Frequency Features

Refinement Analysis for Time-Frequency Characteristic of Blasting Seismic Exploration Signals

2014 ◽  
Vol 926-930 ◽  
pp. 3541-3544
Author(s):  
Ming Shou Zhong ◽  
Quan Min Xie ◽  
Tao Guo ◽  
Xing Bo Xie ◽  
Hao Quan Liu ◽  
...  
Keyword(s):  
Wavelet Transformation ◽  
Seismic Exploration ◽  
Blasting Vibration ◽  
Seismic Signals ◽  
Analysis Method ◽  
Effect Analysis ◽  
Time Frequency ◽  
Vibration Effect ◽  
New Research ◽  
Frequency Features

Accurate extraction of time-frequency features for blasting vibration signals has great significance for blasting seismic exploration, so time-frequency analysis method for blasting seismic signals was researched based on frequency slice wavelet transformation technology, and separation and extraction of time-frequency features were were successfully achieved. Frequency slice wavelet transformation can be introduced into blasting vibration effect analysis fields, it can provide a new research idea for refinement analysis of time-frequency characteristics, and it also has great significance for improving the effect of blasting seismic exploration in China.

Fundamental frequency determination based on instantaneous frequency estimation

1995 ◽  
Vol 44 (2) ◽  
pp. 233-241 ◽  
Author(s):  
Lunji Qiu ◽  
Haiyun Yang ◽  
Soo-Ngee Koh
Keyword(s):  
Fundamental Frequency ◽  
Instantaneous Frequency ◽  
Frequency Estimation ◽  
Instantaneous Frequency Estimation ◽  
Frequency Determination

scholarly journals Post-Voltage-Boost Circuit-Supported Single-Ended Class-B Amplifier for Piezoelectric Transducer Applications

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5412
Author(s):  
Jungsuk Kim ◽  
Kiheum You ◽  
Hojong Choi
Keyword(s):  
Piezoelectric Transducer ◽  
Maximum Output Power ◽  
Piezoelectric Transducers ◽  
Maximum Output ◽  
Good Efficiency ◽  
Acoustic Performance ◽  
Current Consumption ◽  
Class B ◽  
Ultrasound Applications ◽  
Pulse Echo

Piezoelectric transducers are important devices that are triggered by amplifier circuits in mobile ultrasound systems. Therefore, amplifier performance is vital because it determines the acoustic piezoelectric transducer performances. Particularly, mobile ultrasound applications have strict battery performance and current consumption requirements; hence, amplifier devices should exhibit good efficiency because the direct current (DC) voltage in the battery are provided to the supply voltages of the amplifier, thus limiting the maximum DC drain voltages of the main transistors in the amplifier. The maximum DC drain voltages are related with maximum output power if the choke inductor in the amplifier is used. Therefore, a need to improve the amplifier performance of piezoelectric transducers exists for mobile ultrasound applications. In this study, a post-voltage-boost circuit-supported class-B amplifier used for mobile ultrasound applications was developed to increase the acoustic performance of piezoelectric transducers. The measured voltage of the post-voltage-boost circuit-supported class-B amplifier (62 VP-P) is higher than that of only a class-B amplifier (50 VP-P) at 15 MHz and 100 mVP-P input. By performing the pulse-echo measurement test, the echo signal with the post-voltage-boost circuit-supported class-B amplifier (10.39 mVP-P) was also noted to be higher than that with only a class-B amplifier (6.15 mVP-P). Therefore, this designed post-voltage-boost circuit can help improve the acoustic amplitude of piezoelectric transducers used for mobile ultrasound applications.

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