Characteristics of broadband matching for piezoelectric ceramic transducer are fully analyzed. It is stated that in the case of without an all pass function, good matching characteristics of maximum bandwidth and gain-bandwidth product are implied in the Butterworth matching theorem. If the parameter σ 〈 .252, it is not helpful to add an all pass function to the circuit following the rule of minimizing center frequency and maximizing gain-bandwidth product.
A transient suppression method for piezoelectric ceramic transducer is presented. By adding some special pedestal pulses to the original transmitted signal, the transient effects in the output of the transducer can be just precisely transmission by use of a narrowband transducer. canceled, thereby achieving the broadband The experimental results show that the transient responses of the sinusoid pulses and coded signals are suppressed successfully and the acoustic waveforms radiated into the surrounding water are improved significantly.
ZHANG Jianlan GAO Tianfu ZENG Juan LI Haifeng LIU Haijun
Prom investigation of the advantages and disadvantages of conventional tri-voltage method,a method for the measurement of the transmitting transducer＇s impedance was presented to solve the difficult problem of examining the consistency of the transmitting phased array on the single-mode excitation sea spot.In the method based on the system function, the circuit structure of tri-voltage method was used but new parameters were measured.The principle of the method was given first.Then when resistors with different nominal values were used in the circuit,the measured results for the impedance of transducers were reported.The results were compared with the higher precision impedance analyzer.Finally,the error analysis was performed according to the impedance formula and the equivalent circuit parameters were fitted.Under the condition of guaranteeing the sampling precision,by performance analyzing, the resistor value in series was chosen relatively smaller than the impedance of transducer,the measurement of impedance could achieve the same precision as the higher precision impedance analyzer.Finally,the least squares curve-fitting of measured curves indicated that the transducer equivalent electrical parameters could be extracted accurately and used to design the matching network.
LI HaifengZENG JuanGAO TianfuLIU HaijunPENG DayongZHAO Wenyao
