JPS6216750A - Ultrasonic diagnostic apparatus - 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 <Industrial Application Field> The present invention relates to an ultrasonic diagnostic apparatus that obtains tomographic images of a human body, etc., using ultrasonic waves.

<Summary of the Invention> The present invention provides an ultrasonic diagnostic apparatus having an electronic focus control unit that outputs multiple systems of ultrasonic reception signals having different focus positions in parallel, in which an input is connected to each of the plurality of outputs, and an output A plurality of variable gain amplifiers are connected in common, and the gain of one amplifier is set to 100%.
By gradually decreasing the gain from zero to zero and gradually increasing the gain of one other amplifier from zero to 100%, the outputs of multiple systems can be smoothly switched and introduced into the display processing section, making it easier to see the image when switching.

<Prior Art> As this type of ultrasonic diagnostic apparatus, one having the configuration shown in FIG. 3 is conventionally known.

In FIG. 3, 10 is a probe composed of a plurality of ultrasonic transducers, 12 is a device that controls and processes the transmitted signal and received signal of the probe 10, and receives two systems of received signals A with different focus positions. an electronic focus control unit that outputs and B in parallel;
14 is a switching unit that selects one of the two outputs A and H of this control unit 12; 16 is a display unit that displays a tomographic image on a CRT based on the signal A″!! or B selected by the switching unit 14; Display processing unit (logarithmically compresses signal A or B, performs envelope detection, and displays the detected signal on a CRT as a video signal)
It is.

As shown in FIG. 4, the switching section 14 is configured to
Two analog switches SWI and SW2 are used to turn ON and OFF the
This circuit consists of a logic circuit 18 that drives I and SW2 in a complementary manner (when one is ON, the other is turned OFF), and a buffer 20 that connects the outputs of both analog switches SWI and SW2 to a common input side. The output of the buffer 20 becomes the input of the display processing section 16.

<Problems to be Solved by the Invention> In the conventional device described above, the signals A and B having different focus positions are selected by the switching unit 14 using the analog switches SW1 and SW2 and introduced into the display processing unit 16. As a result, spike noise occurs when switching signals, which appears on the display screen and distorts the image. It is very difficult to remove this spike noise.

Furthermore, there is a huge difference between the tomographic image produced by signal A and the tomographic image produced by signal B, but since the signals are switched instantaneously using the analog switches SWI and SW2, the switching boundary portion on the display becomes obtrusive and difficult to see.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide an ultrasonic diagnostic apparatus that allows display switching of tomographic images with different focus positions to be easily and smoothly performed.

Therefore, in the present invention, the switching section is provided with a plurality of variable gain amplifiers whose inputs are connected to each output of the electronic focus control section and whose outputs are commonly connected, During steady state, the gain of one of these amplifiers is set to 100% while the gain of the other is set to zero, and when switching, the gain of one amplifier is gradually reduced from 100% to zero, while at the same time the gain of the other amplifier is set from zero to 100%. %.

<Embodiment> The overall schematic configuration of an ultrasonic diagnostic apparatus according to an embodiment of the present invention is the same as the conventional configuration already explained in FIG. 3, and the previous explanation is used for this.

FIG. 1 shows a detailed configuration example of the switching section 14 of the device according to the present invention.

In FIG. 1, 22 and 24 are voltage-controlled variable gain amplifiers (hereinafter referred to as VCA) with the same configuration (double gate).
It consists of FET, resistors R1 to R5, and capacitors C1 to C3. Input signal A or B is one gate of FET)K
The amplified output is taken out from the drain side and input to the common adder circuit 26. Both VCA22.24
The gain of is controlled by the voltages CVI and CV2 applied to the other gate of the FET, respectively.

The control voltages CVI and CV2 are applied from the switching signal generating circuit 26 and change as shown in FIG.

When selecting and displaying the output signal A from the electronic focus control section 12, the control voltage CVI is a predetermined positive voltage, and the gain of the VCA 22 is 100%. Another control voltage VC2 is Ov, and the gain of VCA24 is zero. Therefore, only the signal A that has passed through the VCA 22 is input to the adder circuit 26, and is supplied to the display processing section 16.

When switching from signal A to signal B, the control voltage VCI is lowered from a predetermined value to 0■ at a predetermined ratio, and at the same time the control voltage VCI is reduced from a predetermined value to 0■.
C2 is increased from Ov to a predetermined value.

This is it! The gain of DVCA 22 gradually decreases from 100% to zero, and at the same time the gain of VCA 24 gradually increases from zero to 100%. During this switching period, the sum of the gains of VCA 22 and VCA 24 is always 100%.

Therefore, during the switching period, the signal A is applied to the adder circuit 26.
The input level of signal B gradually decreases, and the input level of signal B gradually increases instead. Then, when the switching is completed, signal A is no longer input, and only signal B is input.

As a result, on the CRT screen in the display processing unit 16, the tomographic image of signal A smoothly changes to the tomographic image of signal B, and no noise or discontinuous portion that is difficult to see occurs.

<Effects of the Invention> As explained in detail above, the ultrasonic diagnostic apparatus according to the present invention is configured to gradually and continuously switch the output of the electronic focus control section, so that the display is not disturbed or difficult to see due to the switching. Boundaries no longer arise.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of the main part (switching part) of a device according to an embodiment of the present invention, Fig. 2 is an operation waveform diagram of the circuit of Fig. 1, and Fig. 3 is common to the embodiment of the present invention and the conventional example. FIG. 4 is a block diagram showing the overall schematic configuration of an ultrasonic diagnostic apparatus, and FIG. 4 is a circuit diagram of the main part (switching part) of the conventional one. 22.24... Voltage controlled variable gain amplifier 26...
addition circuit.

Claims (1)

[Claims] (1) A probe consisting of multiple ultrasonic transducers, and an electronic device that controls and processes the transmitted and received signals of this probe and outputs multiple systems of received signals with different focus positions in parallel. An ultrasound system that includes a focus control section, a switching section that selects one of a plurality of output systems of the control section, and a display processing section that displays a tomographic image based on the signal selected by the switching section. In the diagnostic device, the switching section is provided with a plurality of variable gain amplifiers whose inputs are connected to each output of the electronic focus control section and whose outputs are commonly connected, and during normal operation, one of these amplifiers is connected to the output of the electronic focus control section. gain 1
00% and the other gains are set to zero, and at the time of switching, the gain of one amplifier is gradually decreased from 100% to zero, and at the same time the gain of the other amplifier is gradually increased from zero to 100%. Device.