ISSN (Online) 2321 – 2004

IJIREEICE ISSN (Print) 2321 – 5526

INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN ELECTRICAL, ELECTRONICS, INSTRUMENTATION AND CONTROL ENGINEERING
Vol. 4, Issue 1, January 2016

Design of High Voltage Pulse Generator and

Receiver Circuit for Ultrasonic velocity and
Absorption Measurements In liquids
Dr.Shaik abdul jaffar1, Prof. K. Malakondaiah2, Prof. Y.B. Gandole3
Research Scholar, Department of Instrumentation, Sri Krishna deveraya university, Anantapuramu, India 1
Professor, Department of Instrumentation, Sri Krishna deveraya university, Anantapuramu, India 2
Prof., Dept. of Electronics, Adarsha Science J.B.Arts & Birla Commerce, Mahavidyalaya, Dhamangoan, Rly, India 3

Abstract: This paper discusses the design and development of a single channel transceiver for broad bandwidth
ultrasound applications.. The transceiver has the pulser as transmitter and a broad bandwidth receiver. A high frequency
ultrasound transducer is used both for the transmission of ultrasound pulse and for receiving the ultrasound echoes. The
pulser circuit is a high voltage, high speed, switching circuit designed for 20 V pulse amplitude and pulse width as low
as 10 ns. The preamp is a low noise, wide bandwidth amplifier and the time gain compensation circuit has a low noise
figure and a bandwidth of 15 MHz. Custom, miniaturized PCB’s have been fabricated and tested for the R.F.
electronics. The performance characteristics of 5 MHz transducers are tested and calibrated.
Keywords: Pulse generator, Pulser-Receiver, Ultrasonic measurements.

I. INTRODUCTION
Ultrasonic pulser-receivers are well suited to general pulser-receivers are also used to study frequency
purpose ultrasonic testing. Along with appropriate dependent material properties or to characterize the
transducers and an oscilloscope, they can be used for flaw performance of ultrasonic transducers. This work presents
detection and thickness gauging in a wide variety of circuits that are developed to excite ultrasonic transducers
metals, plastics, ceramics, and composites. Ultrasonic transmitters and to receive the coming signals of ultrasonic
pulser-receivers provide a unique, low-cost ultrasonic transducers receivers [1-3]
measurement capability The pulser section of the
instrument generates short, large amplitude electric pulses II. DESIGN CONSIDERATION
of controlled energy, which are converted into short (i) High frequency pulse generator:
ultrasonic pulses when applied to an ultrasonic transducer. The First part to be designed was the transmitter (Fig.1). It
Most pulser sections have very low impedance outputs to was decided to use an analog circuit to generate the driver
better drive transducers. Control functions associated with frequency, mostly due to better accuracy and reliability.
the pulser circuit include: An LM555 timer constantly provides an square signal of
Pulse length or damping (The amount of time the pulse the 5MHz frequency; this signal is connected to the
is applied to the transducer.) monostable multivibrator which generates pulse width 3
Pulse energy (The voltage applied to the transducer. us. The sample rate is 500 Hz.
Typical pulser circuits will apply from 100 volts to 800 The output of 74121 is applied to the IRF530 Power
volts to a transducer.) MOSFET which utilize advanced processing techniques
In the receiver section the voltage signals produced by the to achieve extremely low on-resistance per silicon area.
transducer, which represent the received ultrasonic pulses, This benefit of the IRF530, combined with the fast
are amplified. The amplified radio frequency (RF) signal switching speed and ruggedized device design that
is available as an output for display or capture for signal HEXFET power MOSFETs are well known for, provides
processing. Control functions associated with the receiver the designer with an extremely efficient and reliable
circuit include device for use in a wide variety of applications. The
Signal rectification (The RF signal can be viewed as amplitude of output pulse uses 60 V peak to peak; which
positive half wave, negative half wave or full wave.) is given to sender transducer (Tx).
Filtering to shape and smooth return signals In the design of a practical pulse generator, parasitic
Gain, or signal amplification capacitors associated with the MOSFETs and the coaxial
Reject control cable connecting to the transducer have to be considered.
These capacitors keep the pulse generator output at high
The pulser-receiver is also used in material voltage for a long period that could saturate the high-gain
characterization work involving sound velocity or echo amplifier and also increase the leakage current that
attenuation measurements, which can be correlated to may create safety issues. Thus, at the end of each pulse
material properties such as elastic modulus. In train, discharging the parasitic capacitors to zero potential
conjunction with a stepless gate and a spectrum analyzer, is essential.

Copyright to IJIREEICE DOI 10.17148/IJIREEICE.2016.4121 88

 ISSN (Online) 2321 – 2004
IJIREEICE ISSN (Print) 2321 – 5526

INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN ELECTRICAL, ELECTRONICS, INSTRUMENTATION AND CONTROL ENGINEERING
Vol. 4, Issue 1, January 2016

Fig.2 Wide band receiver

III. MEASURING TECHNIQUE

Fig. 1: High frequency pulse generator
For the measurement of ultrasonic velocity and
(ii) Wide band Receiver attenuation, the Sender Transducer(Tx) is firmly fixed at
In practical situations, the received echo signal intensity one end of the measuring cell, while Receiving
can be less than 1% of that sending out from the Transducer(Rx) if fixed to movable scale having least
transducer. A high gain amplifier is required to amplify count of 0.005cm.
the echo signal received from the transducer. The circuit The liquid sample was contained in a glass tube as shown
diagram of wideband receiver is shown in figure 2. in figure 3.
An amplifier consists of single stage, which is assembled
by using the AD822 which is a dual precision, low power
FET input op amp that can operate from a single supply of
5 V to 30 V or dual supplies of ±2.5 V to ±15 V. It has
true single-supply capability with an input voltage range
extending below the negative rail, allowing the AD822 to
accommodate input signals below ground in the single-
supply mode.
Output voltage swing extends to within 10 mV of each
rail, providing the maximum output dynamic range. Offset
voltage of 800 μV maximum, offset voltage drift of 2
μV/°C, input bias currents below 25 pA, and low input
voltage noise provide dc precision with source impedances
up to a gigaohm. The 1.8 MHz unity-gain bandwidth, –93
dB THD at 10 kHz, and 3 V/μs slew rate are provided with
a low supply current of 800 μA per amplifier. The output
signal is then fed to LH0002 which is a general purpose
buffer. Its features make it ideal to integrate with
operational amplifiers inside a closed loop configuration to
increase current output. The symmetrical output portion of
the circuit also provides a low output impedance for both
the positive and negative slopes of output pulses.
The AD602 dual-channel, low noise, variable gain
amplifiers are optimized for use in ultrasound imaging
systems but are applicable to any application requiring
precise gain, low noise and distortion, and wide
bandwidth. Each independent channel provides a gain of 0
dB to +40 dB in the AD600 and −10 dB to +30 dB in the Fig: Measuring cell
AD602. The lower gain of the AD602 results in an A glass tube of height 160mm and outer diameter is
improved signal-to-noise ratio (SNR) at the output. 60.5mm and inner diameter is 53.5mm. The glass tube was
However, both products have the same 1.4 nV/√Hz input inserted in an inner space of Double walled chamber
noise spectral density. The decibel gain is directly which was made of brass tubes. Dimensions of double
proportional to the control voltage, accurately calibrated, walled chamber are: height of double walled chamber is
and supply and temperature stable. 145mm, outer diameter 82.7mm and inner diameter is

Copyright to IJIREEICE DOI 10.17148/IJIREEICE.2016.4121 89

 ISSN (Online) 2321 – 2004
IJIREEICE ISSN (Print) 2321 – 5526

INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN ELECTRICAL, ELECTRONICS, INSTRUMENTATION AND CONTROL ENGINEERING
Vol. 4, Issue 1, January 2016

61.5mm. The Double walled chamber was provided with V. CONCLUSION

inlet and outlet for constant temperature water circulation. The stability, accuracy and sensitivity of the system can be
Water circulation arrangement was made through seen from the table1 and table2, It is observed that the
thermostat. The lower surface of the glass tube and double experimental values of ultrasonic velocity and absorption
walled chamber were in the same plane. The lower portion at 5MHz are found to be in good agreement with literature
of Glass tube is partially closed leaving an opening of values. All the measured values are within 0.02%
24mm diameter in which a gold plated X-cut Quartz accuracy. Thus the proposed design shows good
crystal of natural frequency 5MHz and of approximately performance.
20mm diameter is held firmly with a Silicon O-ring. The
Crystal is kept pressed by a Silicon O-ring held in position REFERENCES
by three screws and tightened with optimum pressure. The
[1] Auld, B.A., Acoustic Fields and Waves in Solids, Vol I & II, 2nd
Crystal is in direct contact with the medium under edition Krieger Publishing Company, February 1990; ISBN:
investigation. 089874783X
[2] Cartz, Louis, Nondestructive Testing : Radiography, Ultrasonics,
The Receiving Transducer Rx is kept in Crystal holder Liquid Penetrant, Magnetic Particle, Eddy Current, ASM Intl;
assembly and the Crystal is kept pressed by a Silicon O- ISBN: 0871705176
ring and tightened with optimum pressure by using chuck [3] Krautkramer, Josef and Krautkramer, Herbert, Ultrasonic Testing
of Materials, 4th/revised edition, Springer Verlag, November 1990,
nut. The Receiving Transducer Rx is coupled to ISBN: 0387512314
micrometer via Crystal holder pipe and Dottle–Neck [4] Takagi T., Sawada K., Urakawa H., J. Chem. Thermodynamics.,
arrangement. The micrometer screw is having a pitch of vol. 36, pp.659, 2004.
0.05mm and it is connected to Stepper motor via Universal [5] N.Santhi, P.L. Sabarathinam, J. Madhumitha, G. Alamelumangai,
M.Emayavaramban, Intl. letters of Chem. Phys. and Astro., vol.2 ,
Coupling. Knowing the distance and transit time, pp.18, 2013.
Ultrasonic velocity and absorption measurements can be [6] F.Plantier et al. , J. phys. D: appl. Phys. vol.35, pp.1063, 2002.
computed. The transmitting and received pulse is [7] Agnihotri P. K., Adgaonkar C. S.,Theoretical evaluation of
displayed on personal computer using ADC card. ultrasonic velocity in binary liquid mixtures, Research and Industry,
vol.33,pp.139, 1988.
[8] S. Hawley, J. Allegra and G. Holton., J. Acoust. Soc. Amer.,
IV. RESULT AND DISCUSSION vol.47, pp.137- 143, 1970.
The system is checked by measuring the ultrasonic
velocity and absorption in some organic and n-alcohols
liquids at 5 MHz frequencies and at 30ºC temperature
Table 1 shows the comparison between the literature
values and measured values of ultrasonic velocity for the
liquid samples.
Table 2 shows the comparison between the literature
values and measured values of ultrasonic absorption for
the liquid samples.
Table1. Ultrasonic velocity measurements at 30°C for
5MHz Frequency
Ultrasonic velocity
S. (m sec¯¹)
Sample Reference
No Present Literature
study value
1 Benzene 1286.52 1286.00 Takagi et al⁴
2 n-Hexane 1052.32 1052.00 N. Santhi et al⁵
3 Methanol 1087.46 1087.00 Plantier et al⁶
4 n-Propanol 1192.19 1192.80 N.Santhi et al⁵
5 n-Butanol 1225.51 1225.00 Plantier et al⁶

Table2: Ultrasonicabsorption measurements at 30⁰C for

5MHz Frequency
Ultrasonic absorption
coefficient
S. Sample α/f2(10-15 Np m¯¹Hz-²) Reference
No Present Literature
study value
1 Benzene 909.89 909.81 Agnihotri p. k. et al⁷
2 n-Hexane 54.50 53.50 Stephen hawley et al⁸
3 Methanol 31.90 31.70 Stephen hawley et al⁸
4 n-propanol 62.50 62.70 Stephen hawley et al⁸
5 n-Butanol 77.27 77.40 Stephen hawley et al⁸

Copyright to IJIREEICE DOI 10.17148/IJIREEICE.2016.4121 90