JPS63181745A - 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 device, and in particular, in a signal processing circuit of an ultrasonic diagnostic device, the present invention is applicable to ultrasonic probes with different generated ultrasonic frequencies. The technology relates to a technology that allows the acquisition of images with high quality images.

C. Prior Art] As shown in FIG. 7, the ultrasonic reception processing circuit of a conventional ultrasonic diagnostic apparatus processes an ultrasonic reception signal (hereinafter referred to as echo) obtained by the transducer IA of the ultrasound probe 1. A signal (referred to as a signal) is amplified by a preamplifier 2 and passed through a variable bandpass filter 3. This variable bandpass filter 3 is controlled according to the ultrasonic frequency of the transducer IA. Control of the variable bandpass filter 3 is performed using a ROM (Read Only Me) in which various conditions of the ultrasound probe 1 are stored.
4 is read out by a controller (control device) 5 consisting of a computer or the like, and the data is converted into an analog signal by a digital-to-analog (D/A) converter 6. The variable bandpass filter 3 also changes the filter frequency depending on the depth of the object.

The signal that has passed through the variable bandpass filter 3 is T
GC (Time Ga1n Compensation)
n) 7, the echo signal is amplified by changing the amplification factor in accordance with time, detected by a detection circuit 8, the carrier wave of the echo signal is extracted, and the low-pass filter 9 extracts the envelope of the signal. This extracted signal is sent to a display device 11 through a digital scan converter (DSC) 10.
displayed as an ultrasound image on the screen.

In this way, the variable band that can change the frequency of the bandpass filter in accordance with the frequency of the transducer IA of the ultrasound probe 1 for the echo signal (ultrasonic reflected wave signal including the carrier wave of the signal) Pass filter 3 was prepared. Also, depending on the device, the same ultrasound probe 1 may be used with a dynamic filter method that continuously changes the frequency of the bandpass filter for echo signals from near the body surface and echo signals from deep places. We are trying to improve the image quality.

[Problem that the invention seeks to solve]

However, in the ultrasound receiving circuit of conventional ultrasound diagnostic equipment, the detection circuit 8 and subsequent parts that detect the carrier wave and extract the carrier wave of the echo signal only perform filter processing with a fixed low-pass filter 9. The carrier wave may not be removed sufficiently due to the relationship between the variable band pass filter 3 and the low pass filter 9 after detection, or the frequency band of the carrier wave of the echo signal becomes narrow, resulting in poor frequency response and poor image quality. There was a problem.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a technique in which an ultrasonic wave reception processing circuit of an ultrasonic diagnostic apparatus can obtain good ultrasonic images even when using ultrasonic probes that generate ultrasonic waves with different frequencies.

These and other objects and novel features of the invention are set forth in the following description of the specification and the accompanying drawings.

Means for Solving Problem C] Among the inventions disclosed in this application, a brief overview of typical inventions is as follows.

In other words, an ultrasonic transceiver circuit that sends and receives ultrasonic signals to and from the transducer of an ultrasonic probe, an amplifier circuit that amplifies echo signals, a variable bandpass filter that leaks the amplified echo signals, and a filter (leakage circuit). An ultrasonic diagnostic apparatus equipped with a detection circuit that detects an echo signal generated by a wave (wave) and a low-pass filter that filters (leakage) the detected signal, the filter (leakage) frequency of the low-pass filter being configured to be variable. The present invention is characterized in that a filter (leakage) frequency variable means for changing the filter (leakage) frequency by an external signal is provided.

[Effect]

According to the above-mentioned means, the filter frequency of the low-pass filter is configured to be variable, and the filter frequency variable means for changing the filter frequency by an external signal is provided, so that the band-pass filter for the carrier wave processed at the previous stage is provided. Since the filter frequency of the low-pass filter is changed in accordance with can also be controlled so that the frequency response does not deteriorate.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be specifically described using the drawings.

In addition, in all the episodes, parts having the same function are given the same reference numerals.

FIG. 1 is a block diagram showing a schematic configuration of an ultrasonic wave reception processing circuit of an ultrasonic diagnostic apparatus according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a configuration of a variable low-pass filter shown in FIG. 1.

FIG. 3 is a circuit diagram showing the configuration of the variable bandpass filter of FIG. 1.

As shown in FIG. 1, in the ultrasonic reception processing circuit of the ultrasonic diagnostic apparatus of this embodiment, the echo signal obtained by the transducer IA of the ultrasonic probe I is amplified by the preamplifier 2, and the It is passed through a band pass filter 3. This variable bandpass filter 8 is controlled according to the ultrasonic frequency of the transducer IA.

Control of the variable bandpass filter 3 is performed using a ROM (Read 0) in which various conditions of the ultrasound probe 1 are stored.
nly Memory) 4 is read out by a controller (control device) 5 consisting of a computer or the like, and the data is converted by a digital-to-analog (D/A) converter 6 into an analog signal. The variable bandpass filter 3 also changes the filter frequency depending on the depth of the object.

The signal that has passed through the variable bandpass filter 3 is T
G C (Time Gain Compensat)
ion) 7 by changing the amplification factor in accordance with time, the detection circuit 8 detects the echo signal to extract the carrier wave of the echo signal, and the variable low-pass filter 20 extracts the envelope of the echo signal. This extracted signal is sent to the display device 1 through the digital scan converter 10.
It is displayed as an ultrasound image on the screen of 1.

The variable low-pass filter 20 is controlled by a ROM (Read Only Memory) in which various conditions are stored under the control of a controller 5 consisting of a computer or the like.
y) 4 and a digital/analog (D/A) converter 6 for converting its output into an analog signal, the filter (leakage) frequency is varied according to the carrier frequency.

The specific configuration is, for example, as shown in FIG. 2, a resistor R is connected in series to the signal line SL to which the output terminal of the detection circuit 8 is connected, and the signal line S
A voltage variable capacitor (varicap diode) C2 is connected to L, and a large capacitance DC voltage (D
C) A cutting capacitor C1 is connected, and a resistor R□ is connected between the direct current (DC) cutting capacitor C1 and the voltage variable capacitor C2 as shown in Fig. 4 (in Fig. 4, tl is the display image). A control voltage VC as shown in (which is the scanning time of one line in the depth direction) is applied. 5 and 6 show the pulse characteristics of the echo signal when the filter frequency of the variable low-pass filter 20 is changed. FIG. 5 shows the pulse characteristics of an echo signal for extracting the echo signal from a deep part of the subject, and is used when the carrier frequency is high to improve the pulse characteristics of the echo signal. Also, the 6th
The figure shows the pulse characteristics of the echo signal used to extract the remaining part of the object, and is used when the carrier frequency is low.
This is to ensure that the envelope of the echo signal is sufficiently captured.

Next, the specific configuration of the variable bandpass filter 3 is as shown in FIG. An inductance L, a damping resistor R, and a DC voltage cut capacitor C□ are connected to the inductance L, and a voltage variable capacitor c2 is directly connected in series to the voltage cut capacitor C1. Voltage variable capacitor type and capacitor c
2 and the DC voltage cut capacitor C1 through a resistor R2 as shown in FIG.
C is applied.

The voltage variable capacitor C2 has a capacitance that changes depending on the control voltage VC, and can be realized by, for example, a varicap diode.

In this way, the conventional low-pass filter 9 is replaced with a variable low-pass filter 20, and filter frequency variable means for varying the filter (leakage) frequency of the variable low-pass filter 20 by the control voltage VC from the controller 5 is provided. Accordingly, the filter frequency of the low-pass filter is changed as shown in FIGS. 5 and 6 in accordance with the band-pass filter for the carrier wave processed in the previous stage, and the frequency band of the carrier wave of the echo signal is set to the optimum condition. Since the pulse characteristics of the echo signal can be improved, the carrier wave can be sufficiently removed by the relationship between the band pass filter of the echo signal and the low pass filter after detection, and as shown in Figure 6. , even if a wide frequency band signal with good pulse characteristics is received as the carrier wave of the echo signal, the frequency response will not deteriorate.

In other words, it is possible to optimize the filter characteristics of the carrier wave of the echo signal according to the frequency of the ultrasound probe and the carrier frequency that changes with the dynamic filter.
The distance resolution of ultrasonic echo signals is improved. As a result, it is possible to obtain ultrasound images of good image quality even with ultrasound probes that generate ultrasound waves at different frequencies.

The present invention has been specifically explained above using examples, but
It goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit thereof.

〔Effect of the invention〕

As explained above, according to the present invention, by optimizing the filter characteristics of the carrier wave of the echo signal according to the frequency of the ultrasound probe and the carrier frequency that changes with the dynamic filter, Distance resolution can be improved. As a result, it is possible to obtain ultrasound images of good image quality even with ultrasound probes that generate ultrasound waves at different frequencies.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of an ultrasonic wave reception processing circuit of an ultrasonic diagnostic apparatus according to an embodiment of the present invention; FIG. 2 is a circuit diagram showing a configuration of a variable low-pass filter in FIG. 1; FIG. 3 is a circuit diagram showing the configuration of the variable bandpass filter in FIG. 1. FIG. 4 is a waveform diagram of the control voltage signal of the variable low-pass filter. A pulse characteristic diagram of an echo signal of a low-pass filter showing the effects of an example operation. FIG. 7 is a block diagram showing a schematic configuration of an ultrasonic reception processing circuit of a conventional ultrasonic diagnostic apparatus. In the figure, 1... Ultrasonic probe, IA... Ultrasonic transducer, 2... Preamplifier, 3... Variable band pass filter, 4... ROM, 5... Controller, 6 ...
D/A converter, 7...TGC18...Detection circuit, 9
...Low pass filter, 10...DSCll...
- Display device, 20... is a variable low-pass filter. Kaya 2 Koko S Ko 4th

Claims (1)

[Claims] (1) An ultrasonic transceiver circuit that sends and receives ultrasonic signals to and from the transducer of the ultrasonic probe, an amplification circuit that amplifies the received ultrasonic signal, and a variable band that leaks the amplified received ultrasonic signal. An ultrasonic diagnostic apparatus comprising a pass filter, a detection circuit for detecting a leaked ultrasonic reception signal, and a low-pass filter for leaking the detected signal, wherein the leakage frequency of the low-pass filter is made variable. 1. An ultrasonic diagnostic apparatus comprising: a leakage frequency variable means for changing the leakage frequency by an external signal.