JPS58165826A - Ultrasound diagnostic equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic diagnostic apparatus, and in particular, to an ultrasonic diagnostic apparatus, in which the gain distribution of each of a transmitting amplifier and a receiving amplifier is optimized under optimal conditions with respect to the overall gain of the transmitting amplifier and receiving amplifier. The present invention relates to an ultrasonic diagnostic apparatus having control means.

Figure 1 shows a schematic configuration of an example of a general ultrasonic diagnostic apparatus. In the figure, 1 is an ultrasonic pulse signal generator, 2 is a transmitting amplifier, 3 is a scanner, 3α is a transducer, 4 is a receiving amplifier, 5 is a detector, 6 is an analysis section, 7 is a display section, 8 is a control section, 9 indicates a living body.

In addition, 10 is STC (5 intensity Tim
e control ) signal, which controls the sensitivity of the receiving amplifier to a level corresponding to the depth of the living body in synchronization with the one-pulse signal.

The ultrasonic pulse signal output from the signal generator 1 is amplified to an appropriate power level by the transmission amplifier 2, and then sent to the scanner 3.
drive the transducer 3α inside. The ultrasonic signal projected from the transducer 3α to the living body 8 is detected by the transducer 3α as an echo signal from inside the living body, is amplified by the receiving amplifier 4, is detected by the detector 5, and is detected by the analyzer 6 as needed. After performing the analysis process, it is added to the display section 7 as a luminance signal. On the other hand, a sweep signal generator (not shown) in the display unit 7 generates a sweep signal for the CRT based on the scanning control signal for the scanner 3 and the STC signal, and displays a biological image on the C'RT.

By the way, since the level of the echo signal changes greatly depending on the diagnostic conditions and the state of the living body 3, it is necessary to adjust the signal given to the detector 7 to an appropriate level. For this reason, the gain of the transmitting amplifier 2 or the receiving amplifier 4 is adjusted.

In most conventional ultrasonic diagnostic devices, gain adjustment is performed only on the gain of the receiving amplifier, and some pulsed Doppler blood flow measuring devices have a transmitting amplifier and a device that adjusts the gain of the transmitting amplifier. The only thing that could be seen was that the gains of the receiving amplifier and each were adjusted separately. However, in the former case, there is a possibility that a larger amount of transmitted energy than necessary may be emitted into the body, and in the latter case, it is time-consuming to adjust the gain separately. There are b drawbacks.

Object of the invention and the object of the present invention is to provide an ultrasonic diagnostic apparatus having means for optimally adjusting the gains of both a transmitting amplifier and a receiving amplifier so as not to project more energy than necessary into a living body. be. For this purpose, it is necessary to increase the sensitivity of the receiving side, that is, the gain of the receiving amplifier as much as possible within the range permitted by the conditions, and to suppress the required ultrasonic transmission energy to a small level.

The present invention provides an ultrasonic diagnostic apparatus having a variable gain transmitting amplifier for driving ultrasonic waves and a variable gain receiving amplifier for ultrasonic receiving, and provides a When considering the possible noise level, in the region below the noise level of the receiving amplifier, the gain of the receiving amplifier is held at approximately 1, and the gain of the transmitting amplifier is made variable, and In a region where the noise level of the receiving amplifier exceeds AO, the gain of the transmitting amplifier is maintained at the maximum allowable value and the gain of the receiving amplifier is made variable. Here are some of the features.

A milk dog serpent The present invention will be explained in detail below based on examples.

As mentioned above, in order to minimize the energy projected onto the living body, it is sufficient to increase the sensitivity of the receiving amplifier. but,
Since the level of the received signal to be handled usually reaches the minute order of μV, relying only on the gain of the receiving amplifier may result in a poor signal-to-noise ratio.

In general, the noise level of an ultrasound diagnostic device is determined mostly by the noise characteristics of the receiving amplifier.The noise level of the receiving amplifier is determined by the characteristics of the first stage of the amplifier, so if the gain of the amplifier is increased, the noise level will also be proportional. and then go up. Second
The characteristic line @ shown in the figure shows the relationship between the gain and noise of such an amplifier. Note that the vertical axis in the figure represents the noise level, and the horizontal axis represents the gain of the amplifier. On the other hand, noise may be tolerated up to a noise level below the measurement accuracy of the device, for example, below the minimum display unit in the case of digital display. Second
The dotted line ■ in the figure indicates the noise tolerance level. In the case of the figure, 1. This corresponds to the noise level when the total gain is 90 dll.

Incidentally, the increase in the gain of the transmitting amplifier reduces the signal 1 novelty by increasing 1. Since it does not affect the noise level, it improves the SN ratio.

FIG. 3 is a graph showing the gain distribution characteristics of the transmitting amplifier and receiving amplifier employed in this embodiment. In the figure, the vertical axis represents the distributed gain of each amplifier, and the horizontal axis represents the target total gain. Straight lines (C) and (C)' show the distributed gain characteristics of the receiving amplifier, straight lines (2) and (2) show the distributed gain characteristics of the transmitting amplifier, and (2) shows the combined total gain.

In the region where the total gain is from 46 dB to 90 dB,
The gain of the receiving amplifier is kept constant at 40 dB as shown in (■). On the other hand, the gain of the transmission amplifier is Od
B to 50 dBt. Here, the reason why the gain of the receiving amplifier is maintained at 40 dB is that the total gain is 40 dB.
At the position shown in Fig. 2, the optimal value is to bear the total gain only by the gain of the receiving amplifier, based on the noise characteristics shown in Figure 2.
In addition, in the range where the total gain is 90 dBt, if the gain burden of the receiving amplifier is increased by 1-, the second
This is because the noise level exceeds the noise tolerance shown in the figure, so it is necessary to cover the noise level with a gain amplification port of the transmitting amplifier.

Next, in a region where the total gain exceeds 90 dB, the gain of the transmitting amplifier is increased further to suppress the energy projected to the cow's body, and the gain of the receiving amplifier is increased to maintain the constant value of 50 dB shown in ■ Increase as shown in ''.

In case B, increasing the gain of the receiving amplifier also increases the noise level, but since the gain of the transmitting amplifier is increased by 50 d'B, the problem of deterioration of the S/N ratio is alleviated.

In this way (7), the gain of the transmitting amplifier and the gain of the receiving amplifier are distributed under optimal conditions according to the target overall gain.

FIG. 4 is a configuration diagram of this embodiment. In the figure (8, 2
．． 3.3a14 is a common element with the circuit 17 shown in FIG. 10 is a gain distribution circuit which simultaneously supplies gain control signals 12 and 13 according to the gain distribution characteristics shown in FIG. 10 may have the same structure as a well-known function generator, and can be simply realized by an interlocking potentiometer as shown in FIG.

On the other hand, the amplifiers 12 and 13 are configured by variable gain control type (AGC) amplifiers.

As another embodiment, a potentiometer mechanism as shown in FIG. 5 may be inserted into the signal circuit of each amplifier to directly switch the signal attenuation level. Further, the STC signal is configured to act on different amplification stages of the reception amplifier 4.

As described above, according to the present invention, ultrasonic diagnosis
It becomes possible to easily perform optimal gain distribution according to an arbitrary total gain value so that the ultrasonic signal energy of the cutting device does not increase unnecessarily.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a general ultrasound diagnostic device, Fig. 2 is an explanatory diagram of the noise characteristics and noise tolerance level of the amplifier, Fig. 3 is an explanatory diagram of the gain distribution method in this embodiment, and Fig. 4 is an explanatory diagram of the gain distribution method in this embodiment. FIG. 5 is a block diagram showing an example of a gain distribution circuit. In the figure, 2 is a transmitting amplifier, 3 is a scanner, 3α is a transducer, 4 is a receiving amplifier, 10 is a gain distribution circuit, and 11
is an adjustment terminal for gain setting, and 12.13 is a gain control signal. Patent applicant: Fujitsu Limited +y@ Figure 2

Claims (1)

[Claims] In an ultrasonic diagnostic device equipped with a variable gain transmitting amplifier for ultrasonic drive and a variable gain receiving amplifier for ultrasonic reception, an acceptable noise level for the purpose of use after the receiving amplifier stage in the device. In a region where the output noise level of the receiving amplifier is below 100 kHz when the receiver is turned on, the gain of the receiving amplifier is maintained so that the output noise level is approximately 100 Ω, and the gain of the transmitting amplifier is made variable; Then, in a region where the output noise level of the receiving amplifier is exceeded, the transmitting and receiving gains are controlled in relation to each other so that the gain of the transmitting amplifier is maintained at the maximum allowable value and the gain of the receiving amplifier is made variable. An ultrasonic diagnostic apparatus characterized by having means for.