Device for determining the acoustic parameters of the receivers of the pressure gradient
The invention relates to a measurement technique, namely the measurement of parameters of piezoelectric transducers. The technical result - the simplification of the device, the extension of the frequency range defined parameters in the direction of low frequencies without increasing the size of the device, providing the possibility of determining the parameters of the receivers of the pressure gradient with a low threshold in any environment, including in the water. The device has low noise, easily realizable in the computer system. Device for determining the acoustic parameters of the receivers of the pressure gradient contains a rigid pipe, the first end of which is mounted a first emitter, electrically connected to the signal generator. Inside the pipe is installed the test receiver pressure gradient and the first measuring pressure receiver, electrically connected respectively with the first and second input switch, the output of which is connected to the input of recording equipment. The rigid tube is closed at its second end has a second emitter, identical to the first, is connected to the signal generator through the phase shifter. In the Central part jesd the cross section of which is tightly and rigidly fastened along the contour of the inner surface of the sleeve bimorph bending sensor element. When the metallic sleeve is a wall of the Central part of the rigid pipe, and the device entered the second measuring pressure receiver, identical to the first set with him coaxially and symmetrically on opposite sides of the test receiver pressure gradient and electrically connected to the third input of the switch. 1 C.p. f-crystals, 3 ill.
The invention relates to a measurement technique, namely the measurement of parameters of piezoelectric transducers.
Acoustic receivers pressure gradient are quite small and yet have the focus, which makes them particularly attractive for solving a number of tasks directional reception at low frequencies.
One of the most common types of receivers, the pressure gradient is the receiver of the pressure gradient, made in the form of bending bimorph sensing element which is a thin metal disc, which is glued piezo disk, fixed on the contour to a massive sleeve (FCB) [1, S. 314-316]. The application solves the problem of determining the parameters of the receivers of the pressure gradient this construca and metrological characteristics in particular, the frequency response of the sensitivity and directivity, which characterize the receiver and its scope. Characteristics required to determine, periodically, to confirm, check them out depending on the term and conditions.
A device that provides a measurement of the frequency characteristics of sensitivity and directional acoustic receivers, pressure gradient, built on the principle of direct comparison with the exemplary receiver pressure in “free-field”, and only if both of the receiver affects the true plane wave.
Such a device comprises a generator, electrically coupled to the emitter, turning the device on which you installed the exemplary omnidirectional receiver pressure and the test receiver pressure gradient, is connected through a switch to registering devices [1, C. 85].
The same device provides the definition of the pattern and characteristics of sensitivity in the near zone “free field”.
However, the difficulties of measurement in the far and near zones are mainly associated with the challenges of ensuring the conditions of “free field” and so is x devices for rotating converters in different planes [1, S. 89].
It is known device, devoid of the limitations associated with the measurement in the “free field”, based on the use of pipes Bauer with standing wave. The device is a closed segment of a tube with rigid walls, which are suspended on soft suspension and varies entirely located in the pipe fluid and the test receiver pressure gradient. At the end of the pipe has an accelerometer. The fluid within the pipe segment, moves as a small plot of system with standing wave and has a very specific distribution of pressure amplitude and oscillation speed. If we measure the vibrational speed of the pipe ends using the accelerometer, the oscillation velocity and pressure at any point of the closed pipe can be calculated, and then, knowing the open-circuit voltage from the output of the receiver pressure gradient to calculate its sensitivity [2, S. 184].
However, this device is complicated in technical execution, because it requires the creation of a harmonic generator of mechanical vibrations, suspensions, allows operation only with the inertial environment (water) and provides only discrete building pattern associated with posledovat similar set of features of the present invention is a device described in [2, C. 182]. The device is open at one end with a vertical tube at the closed end of which has an emitter connected to the input of the signal generator. In the inner cavity of the pipe installed measuring omnidirectional receiver pressure and the test receiver pressure gradient is fixed on the rotary device. The outputs of the measuring receiver pressure and the test receiver pressure gradient across the switch is connected with the input of the recording equipment. The pipe is filled with water.
Standing waves, excited by the emitter in the liquid column between the emitter and the reflecting surface water-to-air impinges on the receiver pressure gradient and measuring the pressure receiver. Stress values with these receivers come to registration apparatus, and calculates the sensitivity of the test receiver pressure gradient pressure. The directivity of the receiver pressure gradient is logged when the rotation shaft of the rotary device from 0° up to 360°.
The disadvantage of this device is the limited application due to the need of use environments, providing at the interface imped is th at low frequencies, a low level of sound pressure that is required to define the parameters of the receivers of the pressure gradient with a low threshold, the creation of mechanical devices for rotation in a given plane and with sufficient accuracy. The device provides in a vertical position only.
The objective of the invention is to provide an effective acoustic device for determining parameters FCB, devoid of the drawbacks of the prototype.
Technical results of the claimed invention is the simplification of the device, the extension of the frequency range defined parameters in the direction of low frequencies without increasing the size of the device, providing the possibility of determining the parameters FCB with a low threshold in any environment, including water, has a low noise level, easily realizable in the computer system.
To achieve the said technical result in the device for determining the acoustic parameters of the receivers of the pressure gradient, containing a rigid pipe, the first end of which is mounted a first emitter, electrically connected to the signal generator, and inside the pipe is installed the test receiver gladiatorum input switch, the output of which is connected to the input recording equipment, introduced new features, namely: a rigid tube is closed at its second end has a second emitter, identical to the first, is connected to the signal generator through the barrier in the Central part of the rigid pipe is installed the test receiver pressure gradient, consisting of a metal sleeve, cross-section which is installed tightly and rigidly fastened along the contour of the inner surface of the sleeve bimorph bending sensor element, when the metallic sleeve is a wall of the Central part of the rigid pipe, and the device entered the second measuring pressure receiver, identical to the first, mounted coaxially with him and symmetrically on opposite sides of the test receiver pressure gradient and electrically connected to the third input of the switch.
The construction of the claimed device is simplified, and the efficiency is increased if the first and second receivers pressure is made in the form of a cylindrical piezoceramic transducers, forming symmetrical with respect to the test receiver pressure gradient sections of rigid pipe.
Explain Costigan the GB, located at a distance sleeve lengthx apply pressure, the difference due to the phase shiftx (pressure gradient), leads to the fact that the diaphragm and the piezoelectric disc sags, and voltage at the output of the piezoceramic disk will be expressed by the formula
where- circular frequency, C is the speed of sound in the environment,the angular position of the receiver pressure gradient to the source, the P - value of sound pressure, Mx(t) is the sensitivity of the FCB to the pressure, f is the frequency.
The expression (/x cos) is the phase shift in a flat wave (phase delay) at a distance ofx and an element of the irregular pattern of expression (1), in which the voltage at the output FCB depends on the phase difference of pressure acting on the acoustic inputs receiver pressure gradient, a certain angular position of the receiver on the source of the sound. It follows that if you create a device that will provide Agostino angle FCB, the recording equipment shall record the output FCB voltage e, which is irregular pattern obtained without actual rotation around the axis perpendicular to the generatrix of FCB. To implement this method, it is proposed to use a closed segment of a tube with emitters on the ends and FCB in the center of this tube, dividing the volume of this pipe bending in two sensitive bimorph element. Each of the emitters organizes resulting in the camera sound pressure and phase shift of one relative to another will be determined by the phase shifter, connected in series with one of the emitters. When changing the phase delay in the range from 0 to (/x cos) continuously or discretely, you can get the pattern without the use of a rotary device.
While measuring receivers pressure fix the sound pressure in the pipe, and average the two readings of the voltage eswill be proportional to
Comparing the values of eSfor=0 and e, from expressions (1) and (2) will get the value of the f) - the dependence of the sensitivity on the frequency of the measuring receiver pressure.
Thus, the frequency response of the sensitivity and directivity FCB may be obtained in the proposed device without the use of mechanical rotary device. When measuring in the air provided a low impedance across the volume of the chamber, so the receiver of the pressure gradient with a relatively low impedance does not violate the homogeneity of the pressure in each half of the camera saves phase pressure ratio and is a measure of the directivity and sensitivity of the test receiver. The pipe is made rigid, and the drivers are mounted on two end surfaces of the pipe, which results in high pressure created by the emitters and perceived FCB. Measurement in more dense environments (e.g., water) is possible, but requires some design requirements calibrated receivers or will increase the accuracy of the measurements.
The invention is shown in Fig.1, 2, 3, where Fig.1 shows a block diagram of the proposed device of Fig.2 is a diagram of the orientation of the FCB received on the proposed device of Fig.3 pravlenie the device is a rigid closed pipe 1, at the ends of which includes first and second identical emitters 2, 3. The Central part of the pipe is formed by a metal sleeve 4 FCB 5. In the Central section of the sleeve is installed tightly and rigidly fastened along the contour of the inner surface of the sleeve bimorph bending sensor element made in the form of a thin metal disk 6, to which is glued supository the thickness of a thin disc of piezoelectric ceramics 7. To both end surfaces of the metal sleeve, is symmetrical about its Central cross section, the ends of the connecting sleeve 8, 9, attached two piezoceramic cylinder 10, 11, the outer diameter of which is equal to the diameter of the metal sleeve. Piezoelectric cylinders supository in the direction of the radius and function of receiver pressure. In another execution of omnidirectional receivers pressure can be replaced, for example, omnidirectional hydrophones. The emitter 2 is electrically connected to the output of the generator 12, and the emitter 3 - the output of the phase shifter 13, the input connected to the output of the generator 12. The outputs of the measuring receiver pressure 10, 11 and the output of receiver pressure gradient 5 electrically connected with the switch weusa equipment were used appliances company Brual & Kjar, 2010 analyzer and recorder 2307, was also used generator G-103, radiators served as the dynamics of 0.5 GDS - 15. The rotating shaft of the phase shifter was connected mechanically with the drive recorder.
Measurement parameters FCB using the proposed device is as follows. Using the known values, andx determine the maximum value of phase delay
set as the limit on the phase shifter 13.
To determine the pattern set Phaser to zero, include the signal generator 12 and register the adopted measuring receivers, the signal level of the recording apparatus 15. Switch switch to to registering devices was connected FCB. Changing the angle of the phase delay in the range from 0 to (/x cos), wherevirtual angle FCB around its axis, make you check the data readings output FCB emaxaccording to the testimony of recording equipment, then flip the switch and record the reading esthe output of the measuring receiver pressure 9, 10. Changing the frequency of repeat measurements. Determine the frequency response of the receiver sensitivity of the pressure gradient Mx(f) no the formula (3).
Describes the measurement algorithm is easy to implement on computers and low frequencies and unlimited time measurement does not cause difficulties with the technical implementation. The proposed device can be used as test equipment, and as a means of measurements after appropriate procedures for certification or verification.
The proposed device has been manufactured, tested and is currently used in studies of FCB. In Fig.2 and 3 present, respectively, the directional diagram of the FCB, taken at a frequency of 100 Hz during virtual rotation FCB=0°-540°, and the calculated sensitivity pressure Mx(f) in the range of the real phase shifts atx=20,0 mm pipe Sizes (without FCB) do not exceed 120.0 mm and a diameter of 35.0 mm Installation allows you to produce and the enta pressure 0.1-1000,0 µv/PA, that allows us to consider the objective of the invention is resolved.
Sources of information
1. R. Bobber. “Hydroacoustic measurements M., Mir, 1974.
2. G. K. Skrebnev. “Combined hydroacoustic receivers”. SPb., 1997.
1. Device for determining the acoustic parameters of the receivers of the pressure gradient, containing a rigid pipe, the first end of which is mounted a first emitter, electrically connected to the signal generator, and inside the pipe is installed the test receiver pressure gradient and the first measuring pressure receiver, electrically connected respectively with the first and second inputs of the switch, the output of which is connected to the input of the recording apparatus, characterized in that the rigid tube is closed at its second end has a second emitter, identical to the first, is connected to the signal generator through the barrier in the Central part of the rigid pipe is installed the test receiver pressure gradient, consisting of a metal sleeve, cross-section which is installed tightly and rigidly fastened along the contour of the inner surface of the sleeve bimorph bending sensitivity is the device entered the second measuring receiver pressure, identical to the first set with him coaxially and symmetrically on opposite sides of the test receiver pressure gradient and electrically connected to the third input of the switch.
2. The device under item 1, characterized in that the first and second receivers pressure is made in the form of a cylindrical piezoceramic transducers, forming symmetrical with respect to the test receiver pressure gradient sections of rigid pipe.
FIELD: instrumentation engineering.
SUBSTANCE: proposed method includes reception of source noise signal and generation of control signal as function of relative motion parameters of source and receiver prior to measuring waveform and energy width of spectral digital noise component of source noise signal, this control signal being used to convert time scale of noise signal received. In this way generation of control signal and its purposeful change effected by means of time scale of noise signal received enable reduction of distortions in this signal caused by relative motion of noise source and receiver.
EFFECT: enhanced measurement accuracy.
1 cl, 6 dwg
SUBSTANCE: device has hydro-chamber, emitters, hydro-phones and device for tugging and holding calibrated antenna inside hydro-chamber. Emitters and hydro-phones are mounted in hydro-chamber walls oppositely to one another. Hydro-chamber and device for tugging and holding antenna are made in form of separate sections, engaged with one another as a whole unit, and calibrated antenna is electrically and mechanically disconnected from system for reproducing and controlling parameters of hydro-acoustic field (emitters and hydro-phones). Additionally plant has set-point generator, used for generation of signals for emitters.
EFFECT: higher precision, higher efficiency.
8 cl, 6 dwg
FIELD: hydro-acoustics, possible use for express estimation of characteristic of direction of hydro-acoustic emitter.
SUBSTANCE: in accordance to first variant of manufacture, in front of hydro-acoustic emitter, hydro-acoustic receiver is positioned, made in form of grid of sound-sensitive elements. The latter is in its turn made in form of object filament coil of wave-optical interference meter, supporting filament coil of which is mounted also in liquid, but outside the emission field of hydro-acoustic emitter. Also, device additionally has position indicator of hydro-acoustic emitter and electronic circuit for separating maximal input signal with increase in distance between hydro-acoustic receiver and hydro-acoustic emitter. It occurs during filling of all cells of hydro-acoustic receiver with radiation field of hydro-acoustic emitter. Knowing the theory of experiment, estimation of opening angle of main petal of characteristic of direction of hydro-acoustic emitter is performed. In accordance to second variant of device manufacture, in additionally includes hydro-acoustic receiver scanner in grid plane. When at output of interference meter signal appears with scanning frequency of hydro-acoustic receiver in process of approach of hydro-acoustic emitter and hydro-acoustic receiver, estimation of thin structure of characteristic of direction of hydro-acoustic emitter is performed, i.e. presence of additional petals within complete characteristic of direction of hydro-acoustic emitter.
EFFECT: removed flaws of prototype, simplified construction.
2 cl, 4 dwg
FIELD: technology for measuring maximally possible legibility of speech under extremely unfavorable conditions, in the noise, for low signal/noise ratios, and is meant mainly for determining protection of objects during loss of speech information through several leaking channels simultaneously.
SUBSTANCE: in accordance to method, in receipt point K receivers of other signal types, formed by acoustic testing signals, for example, electric, magnetic, vibro-acoustic signals, are positioned, acoustic and aforementioned K signal types formed in receipt position at all N frequencies of testing signal and in pauses between same, are received and measured separately, on basis of results of measurements signal/noise ratios are determined at each frequency of testing signal by each one of acoustic and K other types of received signals, at each frequency of testing signal greatest one of signal/noise relations are selected, measured by acoustic and K other types of received signals, then - speech legibility grade is calculated on basis of greatest signal/noise ratios.
EFFECT: increased trustworthiness of speech legibility measurements.
FIELD: technology for measuring maximally possible legibility of speech in extremely unfavorable conditions, in noise, with low signal/noise ratios and is meant, primarily, for determining protection of objects in case of speech information loss through several leaking channels simultaneously.
SUBSTANCE: device contains generator of acoustic testing signal in form of series of N frequencies with pauses between frequencies, emitter, acoustic signal receiver, N-band device for measuring signal/noise rations and device for computing legibility. In addition, in parallel to receiver of acoustic signal K receivers of other signal types, formed by emission of acoustic testing signal, are mounted, for example, for detecting magnetic, electronic, vibro-acoustic types, while clock generator has additional outputs for organization of K+1 cycles of generator and synchronous control over switch of receivers and selection device.
EFFECT: increased trustworthiness of speech legibility measurements.
FIELD: computation engineering.
SUBSTANCE: method involves carrying out object-oriented measurement tract correction. To carry out it, some test signal frequencies are transmitted of given level in turn. Real level of the acoustic signals is measured at each frequency at their transmission place. The acoustic signal levels are compared to given levels at the same frequencies, measured acoustic signals levels deviations from the given ones are measured and frequency characteristic of the measurement tract is adjusted to compensate the difference between the measured and given acoustic signal levels at their transmission place.
EFFECT: high accuracy and reliability of measurements.
FIELD: computation engineering.
SUBSTANCE: device has object-oriented measurement tract correction mode. The device has test signal generator as sequence of N frequencies distributed over N strip means to which the hearing spectrum is divided with pauses between the frequencies, unit for transmitting test signals, microphone, N-bandwidth signal/noise ratio measurement unit, and computation unit for treating intelligibility. Manual generation frequency switch and pause switch mode is introduced. Level measurement unit is mounted in front of the transmitter. Controllable frequency characteristic adjustment unit is introduced in front of the signal/noise ratio measurement unit.
EFFECT: high accuracy and reliability of measurements.
FIELD: hydro-acoustics, possible use for calibration of linear receiving hydro-acoustic measuring antennas in laboratory conditions.
SUBSTANCE: method for modeling one-dimensional harmonic acoustic fields in extensive narrow closed hydro-chamber includes placing hydro-acoustic emitters in it so that maximal distance between any adjacent emitters does not exceed half of wave length of harmonic field being modeled, and amplitudes of acoustic pressure, created by emitters, satisfy certain ratios.
EFFECT: simplified modeling process.
FIELD: oil and gas industry.
SUBSTANCE: method is implemented by means of the device containing hold-down acoustic emission sensor 2 of resonance type, which is attached to pipeline 1 and has two or more resonance bands mutually spaced as to frequency by not less than one octave, processing unit 3 including in-series connected input amplifier 4, narrow-band filter 5 with low-frequency detector, analogue-to-digital converter 6, amplitude discriminator and analyser on the basis of 7. In addition, there proposed is acoustic emission sensor of resonance type for implementation of the method and calibration method of this sensor.
EFFECT: decreasing electric power consumption at practical implementation of the method on distant objects, increasing sensitivity of acoustic sensor (AS), its resistance to external interference, and improving the accuracy of the obtained measurement results.
14 cl, 4 dwg
SUBSTANCE: hydrophone is placed in a pool at a known distance from the radiator. The radiator is excited with by a linear frequency modulated signal (LFM signal) with known parametres. The hydrophone is exposed to the continuous signal from the radiator. Instantaneous current values of the radiator and output voltage of the hydrophone are then measured, from which the complex frequency dependency of the transient impedance (TI) of the radiator and the hydrophone in the reverberation field of the non-damped hydroacoustic pool is determined. The complex frequency dependency of the TI of the radiator and the hydrophone are then determined in conditions of a free field through sliding complex weighted averaging in the set frequency interval of the complex frequency dependency of the TI of the radiator and the hydrophone in the reverberating field using a weighting function which is given by signal time delays reflected by the measurement pool.
EFFECT: more accurate hydrophone calibration.