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YY/T 1142-2013: Methods of measuring the frequency of medical ultrasonic equipment and probe
YY/T 1142-2013
YY
PHARMACEUTICAL INDUSTRY STANDARD
OF THE PEOPLE'S REPUBLIC OF CHINA
ICS 11.040.50
C 41
Replacing YY/T 1142-2003
Methods of measuring the frequency of medical ultrasonic
equipment and probe
ISSUED ON: OCTOBER 21, 2013
IMPLEMENTED ON: OCTOBER 1, 2014
Issued by: China Food and Drug Administration
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 4
4 Test conditions ... 6
5 Test methods ... 8
Methods of measuring the frequency of medical ultrasonic
equipment and probe
1 Scope
This standard specifies the testing methods for the frequency characteristics of medical
ultrasonic equipment (hereinafter referred to as equipment) and probes with a frequency
range of 0.5 MHz~15 MHz, and the calculation method of relevant parameters.
This standard applies to all types of medical ultrasonic equipment and probes operating
in continuous wave, quasi-continuous wave, or pulse wave states.
2 Normative references
The following documents are essential for the application of this document. For the
dated referenced documents, only the versions with the indicated dates are applicable
to this document; for the undated referenced documents, only the latest version
(including all the amendments) is applicable to this document.
YY/T 0163 Characteristics and calibration of hydrophones for medical ultrasonic
fields
3 Terms and definitions
The following terms and definitions apply to this document.
3.1 nominal frequency
The ultrasonic working frequency of an ultrasonic transducer or ultrasonic transducer
array tuple given by the designer or manufacturer.
3.2 acoustic-working frequency
The actual ultrasonic operating frequency obtained from the analysis in which the
hydrophone is placed at an appropriate position in the sound field and its output signal
is analyzed using the zero-crossing frequency method or spectrum analysis method (see
Figure 1). The arithmetic-mean acoustic-working frequency is used in this standard.
Symbol: fawf
a) ambient temperature;
b) supply voltage;
c) Driving power setting (if any).
4.2 Test equipment
4.2.1 Hydrophone
It shall meet the requirements of Class A or Class B needle-shaped (Z-type) or
membrane-type (M-type) hydrophones specified in YY/T 0163. The size of the
sensitive element is ≤1 mm, the frequency response is 0.5 MHz~15 MHz, and the
flatness is ±3 dB. For some equipment that cannot provide the synchronized trigger
signal required for measurement, an auxiliary hydrophone (Class A or B) may be
required to trigger the oscilloscope.
4.2.2 Oscilloscope
The frequency range is not narrower than 0~100 MHz, and the sensitivity is not lower
than 5 mV/div.
4.2.3 Spectrum analyzer
The frequency range is not narrower than 0.1 MHz~30 MHz, and the dynamic range is
not less than 60 dB.
4.2.4 Hydrophone amplifier
The frequency range is not narrower than 0~15 MHz, and there is an appropriate
amplification factor.
4.2.5 Pulse generator/receiver
Pulse generator: the external pulse leading edge (10%~90%) is < 10 ns, the amplitude
is >50 V, the trailing edge is < 50 ns, the repetition frequency is 0~10 kHz, and the
internal pulse repetition frequency is 100 Hz~10 kHz. Pulse receiver: the bandwidth is
not narrower than 1 kHz~35 MHz(-3 dB).
4.2.6 Water tank and positioning device
The size of the tank shall be such that boundary sound reflection does not have a major
impact on the test. If necessary, sound-absorbing materials can be laid at appropriate
locations in the tank. A positioning adjustment device equipped with a fixed probe and
hydrophone can change the relative position and direction of the probe and hydrophone
in three dimensions. The minimum adjustment displacement shall be less than half the
wavelength of the sound wave.
b) The ultrasonic output power is controlled at an appropriate position.
c) The scanning angle shall be as small as possible.
5.2.3 After turning on the ultrasonic output, adjust the orientation and angle of the
transducer to maximize the signal received by the hydrophone. If necessary, use a
hydrophone amplifier to amplify the signal.
5.2.4 If the equipment under test operates in continuous wave or quasi-continuous wave
mode, the frequency measurement function of an oscilloscope and a digital frequency
meter can be used directly to measure the acoustic-working frequency without using
a spectrum analyzer.
5.2.5 If the equipment under test operates in pulse scanning mode, an additional trigger
signal synchronized with each sound repetition period shall be provided. If this cannot
be provided, an auxiliary hydrophone can be used to provide an oscilloscope
synchronization signal.
5.2.6 Calculation of the arithmetic-mean acoustic-working frequency: Measure f1 and
f2 on the sound pressure waveform diagram or sound pressure spectrum diagram (as
shown in Figure 1), then the arithmetic-mean acoustic-working frequency is calculated
according to formula (1).
where:
f1 and f2 -- f1 and f2 respectively measured on the sound pressure spectrum diagram
(as shown in Figure 1), the unit is megahertz (MHz).
5.2.7 The acoustic-working frequency bandwidth is calculated according to formula (3).
where:
f1 and f2 -- f1 and f2 respectively measured on the sound pressure spectrum diagram
(Figure 1), the unit is megahertz (MHz).
5.2.8 If the equipment has multiple nominal frequencies, the above measurements
shall be made separately for each nominal frequency value and the corresponding
results shall be given.
5.2.9 The spectrum analysis diagram of the signal at the actual working frequency shall
be given. In particular, the component sizes of its second harmonic and other specified