Method for reducing test frequency in limited water area
A technology for testing frequencies and waters, applied in radio wave measurement systems, instruments, etc., can solve the problems of difficult to meet the low-frequency test requirements of sonar equipment, difficult to calibrate the 1kHz operating frequency, etc., to reduce the lower frequency limit and meet the test requirements. Effect
Active Publication Date: 2014-12-10
THE 715TH RES INST OF CHINA SHIPBUILDING IND CORP
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Problems solved by technology
The current free-field calibration method used in China is difficult to achieve the calibration of the 1kHz operating frequency under the existing calibration conditions, and it is difficult to meet the low-frequency test requirements of actual sonar equipment
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[0018] Below in conjunction with accompanying drawing and embodiment the present invention will be further described:
[0019] The complex moving average method differs from traditional methods in that it is based on the characteristic analysis of the target (transmitter, pool and receiver) and the estimation of the transmission impedance of the free-field transmitter and receiver, rather than on signal analysis and separation. The complex moving average method can reduce the reflection effect introduced by the continuous wave in the non-anechoic pool. The complex moving average method uses two linear sweep sine and cosine signals before and after to form a complex signal, and estimates the ratio (transmission impedance) of the excitation signal of the transmitting transducer to the receiving signal of the hydrophone. Time superimposed moving average to reduce the impact of reflected waves on direct waves.
[0020] A description of the theory of the complex moving average met...
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The invention discloses a method for reducing test frequency in a limited water area. The method comprises the following steps that: (1) a signal generator generates a linear sine swept-frequency signal, and exciting a power driver to drive an emitter to generate a signal; (2) the signal received by a receiver passes through a measurement amplifier and then is subjected to data acquisition through a data acquirer, meanwhile, the emitted signal of the signal generator is acquired, and data is stored; (3) the signal generator generates a linear cosine swept-frequency signal, and the processes of the step (1) and the step (2) are repeated; (4) the tested data is processed: complexification is carried out on the emitted signal and the received signal, and the complexification for the emitted signal and the received signal is complex conjugate complexification; mathematical processing of complex conjugate multiplication is carried out on the two processed signals to obtain the transfer function of an echoic water pool; then complex number moving averages processing is carried out on the transfer function.
Description
technical field [0001] The invention relates to the technical field of acoustic testing, and is a method capable of reducing the testing frequency in limited water areas. Background technique [0002] The most important acoustic quantity in the research of underwater acoustic technology is the underwater acoustic sound pressure. The main electroacoustic parameters of various sonar equipment are based on the underwater acoustic sound pressure, and must be calculated by detecting the underwater acoustic sound pressure value. With the development of sonar towards low frequency and large aperture, the test frequency also needs to be widened towards low frequency. [0003] To carry out the free-field calibration of the hydrophone, it is necessary to overcome the reflection in the sound field. Usually, the pulse signal technology is used, and the time-domain method is used to separate the direct signal from the echo signal. The transient processing of this method in the narrow-ba...
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IPC IPC(8): G01S7/52
CPCG01S7/52004
Inventor 平自红王世全陈毅
Owner THE 715TH RES INST OF CHINA SHIPBUILDING IND CORP