JPS59162472A - Reflected wave receiving system for sector electronic scan type ultrasonic diagnosing equipment - Google Patents

Abstract

PURPOSE:To realize a directional characteristic with a high fidelity by receiving signals with transducers in such a manner that they will be attenuated more corresponding to their delay times unavoidably taken to enable compensation for difference in attenuation due to a difference in the propagation length. CONSTITUTION:When a sector electronic scanning is done using a phased array transducer having transducers Eo-En arranged linearly, attenuators ATT1- ATTn are inserted between the transducers E1-En and buffer amplifiers A1-An. A control circuit CONT determines difference of attenuation due to difference in the propagation length of a reflected wave reaching the transducers based on a medium and a sector angle to control the attenuation of the ATT. Thus, the attenuation due to difference in the propagation length can be automatically compensated for by increasing the attenuation corresponding to the prolonged delay being applied thereby realizing the desired directional characteristic with a higher fidelity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reflected wave receiving method in a sector electronic scanning ultrasonic diagnostic apparatus that performs sector electronic scanning using a phased array transducer.

FIG. 1 is a block diagram showing an example of a conventional reflected wave receiving system of this type. In the figure, a plurality of transducers Eo and 'En arranged linearly receive a reflected wave from a reflection source P, convert it into an electrical signal, and buffer amplifier Ao
It is output to the delay line DL via -An. Further, the delay line DL appropriately delays the output of each buffer amplifier Ao=An, that is, applies a larger delay time toward the transducer Eo toward En, and delays the reflected waves from each transducer Eo 7En. This is intended to unify the signals, and these signals are combined into one signal at the output end and sent to the signal processing circuit SP.

However, such a reception method is only intended to unify the received signals, and there is a difference in the propagation length of the ultrasonic wave related to the sector angle θ (comparing both ends, there is Δdo as shown in Figure 1). This ignores the difference in the amount of attenuation of reflected waves received in the medium. In other words, even though the signal strength is weaker as it goes toward Eo with respect to transducer En,
There was a problem in that processing was performed with the same weighting without any compensation (note that signal attenuation on the delay line DL was compensated for by changing the gains of the buffer amplifiers Ao to An).

The present invention has been made in view of these points, and its purpose is to provide a reflected wave reception method that can compensate for differences in the amount of attenuation that ultrasonic waves receive from a medium due to differences in the propagation length of ultrasonic waves during sector scanning. It's about doing.

The configuration of the present invention that achieves this object is characterized in that the more delay time is applied to the received signal of each transducer, the more the attenuation is increased and the signal is received.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 2 is a block diagram showing one embodiment of the present invention. In FIG. 2, the difference from FIG. 1 is that variable attenuators ATTt to ATTn are inserted between each transducer E1 to En and buffer amplifiers A1 to An, and the attenuation amount of each attenuator ATT1 to ATTn is controlled. The point is that a control circuit C0NT is provided to provide control signals necessary for the control.

The control circuit CON determines the difference in attenuation due to the difference in the propagation length of the reflected waves reaching each transducer from the attenuation of the medium and the sector angle θ, and controls the attenuation of each variable attenuator. That is, for the attenuator A T' T n, the attenuation amount α·Δdo (α
is controlled so that the amount of attenuation is equal to the attenuation constant of the medium). Generally, for the first attenuator ATTi, α
Set the attenuation amount to (Δd〇−Δdi).

With this configuration, as more delay is applied to each transducer output, the amount of attenuation increases accordingly, so the difference in the amount of attenuation of the received wave due to the difference in the propagation length to each transducer during sector scanning can be reduced. can be automatically compensated. If attenuation also occurs in the delay line DL depending on the delay time, better compensation can be achieved by setting the attenuator attenuation amount by taking this attenuation amount into account.

In the above explanation, the case where the variation in attenuation is compensated for is shown in the configuration shown in Fig. 2, but any configuration can be used as long as the attenuation on the delay line [lL side is matched with the attenuation in the medium. It may be.

That is, it is sufficient that the attenuation amount per unit delay time of the signal reaching the addition point via the delay line DL is approximately equal to the attenuation amount per unit propagation time in the medium. The reason for this is that in a phased array system, the total delay time of the reflected wave signal propagation from the reflection source P via each element in the delivery aperture plane to the summing point is made to coincide. This is because the taps of the delay line for each element are selected or switched, so if the total delay time is equalized, the attenuation amounts are naturally equalized in the case of the above configuration.

Note that the method of the present invention can be applied not only to wave reception but also to wave transmission. Furthermore, in principle, array transducers are not limited to linear arrays.

As described above, according to the present invention, it is possible to compensate for the difference in attenuation caused by the difference in the propagation length of ultrasonic waves in sector scanning, and it is possible to more faithfully realize desired directivity characteristics.

[Brief explanation of drawings]

FIG. 1 shows an example of a conventional reflected wave receiving system, and is an explanatory diagram.
FIG. 2 shows a sector electronic scanning ultrasound diagnosis 11i according to the present invention.
FIG. 2 is a main part configuration diagram showing an example of a reflected wave receiving method of the device. Eo~[n...Transducer A, o~An...Buffer amplifier DL...Delay line C0NT...Control circuit ATT1~ATTn...Attenuator Patent applicant Yokogawa Medical Systems Co., Ltd. Yaku1 Figure 2

Claims (1)

[Claims] In sector electronic scanning ultrasound diagnostic equipment that performs sector electronic scanning using a phased array transducer in which multiple transducers are arranged in a straight line, Sector electronically scanned ultrasound characterized by compensating for the difference in attenuation that the ultrasound receives from the medium due to the difference in propagation length by receiving it with more attenuation as it takes more time to delay. Reflected wave reception method for diagnostic equipment.