WO2012099341A2

WO2012099341A2 - Medical diagnosis apparatus

Info

Publication number: WO2012099341A2
Application number: PCT/KR2011/009879
Authority: WO
Inventors: 노세범
Original assignee: 알피니언메디칼시스템 주식회사
Priority date: 2011-01-21
Filing date: 2011-12-20
Publication date: 2012-07-26
Also published as: WO2012099341A3

Abstract

The present invention relates to a medical diagnosis apparatus and to a method for operating same. The medical diagnosis apparatus includes a beamformer which divides a frequency band of a reception signal reflected from an object for phase rotation adequate for each band with respect to the reception signal having the divided frequency bands.

Description

Medical diagnostic device

Embodiments of the present invention relate to a medical diagnostic apparatus and a method of driving the apparatus. More specifically, for example, when the ultrasonic medical diagnostic apparatus applies the same amount of time delay to each received signal during beamforming using the received signal, the error caused by the phase rotation amount according to the distance for each frequency component of the received signal is reduced. The present invention relates to a medical diagnostic apparatus capable of improving image quality and a method of driving the apparatus.

The contents described in the following sections provide background information related to the embodiments of the present invention, but it does not constitute a prior art.

In general, an ultrasound system includes a probe including a plurality of conversion elements to transmit and receive an ultrasound signal. When each converter is electrically stimulated, an ultrasonic signal is generated and transmitted to the human body. The ultrasonic signal transmitted to the human body is reflected at the boundary of the internal tissue of the human body, and the ultrasonic echo signal transmitted to the conversion element from the boundary of the human tissue is converted into an electrical signal. An ultrasound image signal for an ultrasound image of the tissue is formed by amplifying and signal processing the converted electrical signal.

As part of performing such a function, the ultrasonic system includes a beamformer. The beamformer plays an important role in securing the resolution of the ultrasound image by changing the shape of the ultrasonic sound field transmitted and received as desired. Conventional beamforming is mainly done using time delay.

1 is a diagram illustrating a transmission / reception beamforming process using a conventional time delay.

In the conventional beamformer, as shown in FIG. 1A, when beamforming and focusing on a point during ultrasonic transmission, the beamformer properly gives a time delay of a transmission pulse applied to each array element inside the array probe. Ultrasound transmitted from the element allows for simultaneous reaching the desired focus. In addition, as in the beamformer of FIG. 1B, the beamformer has the same concept as in FIG. In other words, if you want to focus on a point through receive beamforming, the time from which the signal from the desired focus reaches each element is slightly different. Each signal is delayed so that this time is the same, and then added together.

Meanwhile, in order to implement beamforming at a lower power than a time delay circuit, a method of using a phase rotation circuit is conventionally known. In the case of continuous wave (CW), the time delay is equal to the phase rotation. That is, it may be expressed as Equation 1 below.

Equation 1

2 is a diagram illustrating a general phase rotation circuit.

Referring to FIG. 2, a typical phase rotation circuit may include mixer 1 and mixer 2, and low pass filter (LPF) 1 and LPF 2.

Here, the signal S ₁ output through the mixer 1, the signal S ₂ output through the LPF 1 and the signal S ₃ output through the mixer 2 are represented by Equations 2 to 4, Can be represented as:

Equation 2

Equation 3

Equation 4

However, in the case of a beamformer using a general phase rotation circuit as shown in FIG. 2, the received signal must be a continuous wave (CW) in order for the relationship as shown in Equation 1 to be established. However, most of the signals transmitted and received by the ultrasound diagnosis are not continuous waves because they are fairly wideband. Therefore, the phase rotation method is not ideal for the ultrasound diagnosis, and as a result, many errors occur in image processing.

In particular, when the bandwidth is wide, the error becomes larger, and a representative case is a case where the fundamental and second harmonics are to be received together in the harmonic imaging. At this time, the error will degrade the quality of the image. Here, the wide bandwidth means that several frequency components are mixed together, and when the same amount of time delay is applied to such signals, there is a problem in that the amount of phase rotation is different for each frequency component.

According to an exemplary embodiment of the present invention, when the ultrasonic medical diagnostic apparatus applies the same amount of time delay to each received signal when beamforming the received signal, the error caused by the phase rotation amount according to the distance is different for each frequency component of the received signal. Its purpose is to improve the quality of images by reducing them.

In order to achieve the above object, an embodiment of the present invention, a first filter for extracting the first band signal from the received signal reflected from the object; A second filter extracting a second band signal from the received signal reflected from the object; A first mixer for outputting a first mixing signal by mixing an oscillation signal having a predetermined modulation frequency and a first phase difference φ _{1 with} respect to the received signal with the first band signal; A second mixer for outputting a second mixing signal by mixing the oscillation signal having the modulation frequency and a second phase difference (φ ₂ ) with respect to the received signal with the second band signal; A first low band filter extracting a low frequency band component from the first mixed signal to generate a first low band output; A second low band filter extracting a low frequency band component from the second mixed signal to generate a second low band output; A third mixer for mixing the oscillation signal having the same phase as the modulation frequency and the received signal with the first low band output to output a third mixing signal; A fourth mixer outputting a fourth mixing signal by mixing the oscillation signal having the same phase as the modulation frequency and the received signal with the second low band output; And a beamforming signal generation unit configured to generate a beamforming signal by adding the third mixed signal and the fourth mixed signal after low-band filtering, and adding the third mixed signal.

Each of the first filter and the second filter may use a band pass filter (BPF).

The first phase difference φ ₁ is a phase difference considering the path difference and the frequency of the receiver and the beamforming point of the first band signal, and the second phase difference φ ₂ is the path difference between the receiver and the beamforming point of the second band signal. And phase difference in consideration of frequency.

In order to achieve the above object, an embodiment of the present invention provides a first mixing signal by mixing an oscillation signal having a predetermined modulation frequency and a first phase difference φ _{1 with} respect to a received signal reflected from an object with the received signal. An output first mixer; A first filter extracting a first band signal from the first mixed signal; A second filter extracting a second band signal from the first mixed signal; A second mixer for outputting a second mixing signal by mixing an oscillation signal having a modulation frequency and a third phase difference (φ ₃ ) with respect to the received signal with the first band signal; A third mixer for mixing the oscillation signal having the same phase as the modulation frequency and the received signal with the second low band signal to output a third mixing signal; And a beamforming signal generation unit configured to add the second mixed signal and the third mixed signal and extract a low band signal.

The first filter may use a band pass filter (BPF), and the second filter may use a low pass filter (LPF).

The first phase difference φ ₁ is a phase difference considering the path difference and the frequency of the receiver and the beamforming point of the first band signal, and the third phase φ ₃ is the path of the receiver and beamforming point of the second band signal. It may be a difference value between the phase difference considering the difference and the frequency and the first phase difference φ ₁ .

In order to achieve the above object, an embodiment of the present invention, by receiving a first phase oscillation signal having a first phase difference (φ ₁ ) compared to a predetermined modulation frequency and the received signal reflected from the object from the first phase generator A first mixer for mixing the received signal and outputting a first mixed signal; A first filter extracting a first band signal from the first mixed signal; A second filter extracting a second band signal from the first mixed signal; A subtractor for generating a subtracted signal by subtracting the second band signal from the first band signal; A second mixer for outputting a second mixing signal by mixing the oscillation signal having the modulation frequency and the third phase difference (φ ₃ ) with respect to the received signal with the addition signal; A third mixer for mixing the oscillation signal having the same phase as the modulation frequency and the received signal with the second band signal to output a third mixing signal; And a beamforming signal generation unit configured to add the second mixed signal and the third mixed signal and extract a low band signal.

Each of the first filter and the second filter may use a low pass filter (LPF).

According to an embodiment of the present invention, the ultrasound medical diagnostic apparatus has an effect of improving image quality and realizing low power by performing phase rotation of the same magnitude for each frequency component of the received signal when beamforming using the received signal.

2 is a diagram illustrating a general phase rotation circuit.

Figure 3 is a block diagram showing the structure of a medical diagnostic device according to an embodiment of the present invention.

4 is a first exemplary diagram illustrating the beam transceiver 310 of FIG. 3 and illustrates a block diagram of a broadband phase rotation circuit divided into two frequency bands.

5 is a diagram illustrating a frequency band of a signal generated by the beam transceiver according to the first embodiment of the present invention.

FIG. 6 is a diagram illustrating a second exemplary view of the beam transceiver 310 of FIG. 3.

7 is a diagram illustrating a frequency band of a signal generated by the beam receiver according to the second embodiment of the present invention.

8 is a diagram illustrating a third exemplary view of the beam transceiver 310 of FIG. 3.

9 is a diagram illustrating a frequency band of a signal generated in the beam receiver according to the third embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, in describing the component of this invention, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to that other component, but there may be another configuration between each component. It is to be understood that the elements may be "connected", "coupled" or "connected".

As shown in FIG. 3, the medical diagnostic apparatus 300 according to an exemplary embodiment of the present invention includes, for example, a beam transceiver 310 and an image signal processor 320 as an ultrasound diagnosis device, and includes a memory unit 330 and a key. Some or all of the input unit 340 and the display unit 350 may be further included.

Here, the beam transceiver 310 may be classified into a beam transmitter and a beam receiver as a beam former. The beam transmitter may include a pulse generator, a transmission delay circuit, and a pulser. The pulse generator generates a pulse, the transmission delay circuit delays the pulse, and the pulser uses a delay signal to generate a high voltage, for example, a probe. 360 may be provided.

On the other hand, the beam receiver may include an amplifier, a phase rotation circuit, and the phase delay circuit may selectively include one or more mixers, adders, low band filters, band pass filters, and the like. The amplifier amplifies and outputs, for example, an analog ultrasonic signal received from the probe 360. In addition, the phase rotation circuit divides the received signal provided through the amplifier for each frequency band and applies phase rotation suitable for each band. For example, when the ultrasound diagnosis device adds a time delay to the received signals because the received signal includes several frequency components, an error may occur because the amount of phase rotation varies for each frequency component. By dividing the band, the phase rotation for each band is improved to improve the error.

The image signal processor 310 may include a controller. The image signal processor 310 may process a digital signal provided by the beam receiver under the control of the controller, and temporarily store the digital signal in the memory 320 and then display the digital signal on the display 340. To this end, for example, 8-bit data may be received and converted into 6-bit data, and functions such as ultrasound tomography processing, information processing using the Doppler effect, and 3D image processing may be performed.

The key input unit 330 forms a key or a button for commanding all operations performed in the medical diagnosis apparatus, and the control unit processes related information according to a command input through the key. For example, when a medical staff selects a specific button of the key input unit 330 to view cardiovascular diagnosis information, the medical staff performs a related operation.

4 is a block diagram of a broadband phase rotation circuit divided into two frequency bands as a first exemplary diagram illustrating the beam transceiver 310 of FIG. 3.

Referring to FIG. 4 together with FIG. 3, the beam transceiver according to the first embodiment of the present invention, more precisely, the beam receiver includes a first filter 410, a second filter 420, a first mixer 430, And a second mixer 440, a first low band filter 450, a first low band filter 460, a third mixer 470, a fourth mixer 480, and a beamforming signal generator 490. .

5 is a diagram illustrating a frequency band of a signal generated by the beam transceiver according to the first embodiment of the present invention. Here, it is assumed that the frequency fo of the received signal reflected from the object of the received signal is 2.5 MHz, and the modulation frequency fm of the oscillation signal used for signal mixing is 5 MHz.

A beam receiver according to a first embodiment of the present invention will be described with reference to FIGS. 5 and 4 together.

The first filter 410 receives the ultrasonic wave received signal (received signal a) reflected from the object and incident on the probe 360 to extract the first band signal (b-1), and the second filter 420 A second band signal is extracted from the ultrasonic wave received signal (received signal A, Acos (ω _o t)) reflected from the object (b-2). For example, the first band signal may be Acos (ω ₁ t), and the second band signal may be Acos (ω ₂ t). Here, a band pass filter (BPF) may be used as the first filter 410 and the second filter 420. Each of the band pass filters is for dividing an ultrasonic wave received signal into two frequency bands. However, because the bandpass filter has a wide bandwidth and is not a continuous wave due to the characteristics of the ultrasonic reception signal, the bandpass filter serves to distinguish the bands in order to process the received signal in different ways. Here, processing in different ways means different phase rotations according to different frequency bands.

Here, a band pass filter may be used as the first filter 410 and the second filter 420, but the present invention is not limited thereto.

The first mixer 430 mixes an oscillation signal cos (ω _m t) + φ ₁ having a first modulation difference φ ₁ with a predetermined modulation frequency fm and an ultrasonic reception signal by mixing the first band signal with a first band signal. One mixing signal is output (c-1), and the second mixer 440 has an oscillation signal (cos (ω _m t) + φ ₂ having a modulation frequency fm and a second phase difference φ ₂ relative to the ultrasonic wave reception signal. ) Is mixed with the second band signal to output a second mixed signal (c-2). That is, the first mixed signal is Acos ((ω ₁ -ω _m ) t-φ ₁ ) / 2 + Acos ((ω ₁ + ω _m ) t + φ ₁ ) / 2, and the second mixed signal is Acos ((ω ₂ -ω _m ) t-φ ₂ ) / 2 + Acos ((ω ₂ + ω _m ) t + φ ₂ ) / 2. Here, the first phase difference φ ₁ and the second phase difference φ ₂ are set to be phase differences in consideration of the path between the receiver and the beamforming point of the ultrasonic signal with respect to the frequency component. Therefore, since the first band signal and the second band signal have different frequencies, the phase difference considering the path is also different, so that the mixed signal is modulated and mixed into an oscillation signal having different phase differences.

The first low band filter 450 extracts low frequency components from the first mixed signal to generate a first low band output Acos ((ω ₁ -ω _m ) t-φ ₁ ) / 2 (d-1 The second low band filter 460 extracts the low frequency band component from the second mixed signal to generate a second low band output Acos ((ω ₂ -ω _m ) t -φ ₂ ) / 2 (d -2).

The third mixer 470 mixes the oscillation signal cos (ω _m t) having the same phase as that of the modulation frequency fm and the ultrasonic reception signal with the first low band output, thereby mixing the third mixing signal Acos ((ω _1). outputs t-φ ₁ ) / 4 + Acos ((ω ₁ -2ω _m ) t-φ ₁ ) / 4) (e-1) and the fourth mixer 480 compares the modulation frequency (fm) and the ultrasonic signal received. The fourth mixed signal Acos ((ω ₂ t-φ ₂ ) / 4 + Acos ((ω ₂ -2ω _m ) by mixing the oscillation signal cos (ω _m t) having the same phase with the second low band output t-φ ₂ ) / 4) is output (e-2).

In addition, if the first and

second mixers

430 and 440 convert the signal to an arbitrary frequency while mixing the two signals, the third and

fourth mixers

470 and 480 perform the function of returning back to the frequency before the conversion. You can do it.

The beamforming signal generator 490 may perform the low-band filtering of the third mixed signal Acos ((ω ₁ t-φ ₁ ) / 4) and the low-pass filtering of the fourth mixed signal Acos ((ω ₂ t-φ ₂ ) / 4) is extracted (f) and summed to generate a beamforming signal (g), where phase differences φ ₁ and φ ₂ corresponding to respective frequency components ω ₁ , ω ₂ of the ultrasonic reception signal are obtained. The added beamforming signal is generated.

In addition, the first and second low band filters 450 and 460 perform a function of removing unwanted high band signals generated in the process of mixing the two signals in the first and

second mixers

430 and 440. The beamforming signal generator 490 may perform a function of removing a high band signal generated in the process of mixing the two signals in the third and

fourth mixers

470 and 480.

For reference, in generating the oscillation signal, the phase difference may refer to the phase difference necessary for generating the oscillation signal by using a phase lookup table that lists the phase differences along the path.

Referring to FIG. 6 together with FIG. 3, the beam receiver according to the second embodiment of the present invention may include a first mixer 610, a first filter 620, a second filter 630, a second mixer 640, The third mixer 650 and the beamforming signal generator 660 are included.

7 is a diagram illustrating a frequency band of a signal generated by the beam receiver according to the second embodiment of the present invention. Here, it is also assumed that the frequency fo of the received signal reflected from the object of the received signal is 2.5 MHz, and the modulation frequency fm of the oscillation signal used for signal mixing is 5 MHz.

A beam receiver according to a second embodiment of the present invention will be described with reference to FIGS. 7 and 6 together.

The first mixer 610 has an oscillation signal cos (ω _m t) + having a predetermined modulation frequency fm and a first phase difference φ ₁ relative to the ultrasonic reception signal Acos (ω _o t) reflected from the object. φ ₁ ) is mixed with the ultrasonic reception signal a to mix the first mixing signal Acos ((ω _o -ω _m ) t-φ ₁ ) / 2 + Acos ((ω _o + ω _m ) t + φ ₁ ) / Output 2) (b).

The first filter 620 extracts the first band signal Acos ((ω _o + ω _m ) t + φ ₁ ) / 2 from the first mixed signal (c-1), and the second filter 630 The second band signal Acos ((ω _o -ω _m ) t-φ ₁ ) / 2 is extracted from the first mixed signal (c-2).

The first filter 620 may be a BPF and the second filter 630 may be a low pass filter (LPF), but the present invention is not limited thereto.

The second mixer 640 mixes the oscillation signal cos (ω _m t) -φ ₃ having a third phase difference φ ₃ with respect to the modulation frequency fm and the ultrasonic wave received signal and combines the first band signal with the second band signal. A mixing signal ((Acos ((ω _o t) + φ ₁ + φ ₃ ) / 4 + Acos ((ω ₁ + 2ω _m ) t + φ ₁ -φ ₃ ) / 4)) is output (d-1) The third mixer 650 mixes the oscillation signal cos (ω _m t) having the same phase as the modulation frequency fm and the ultrasonic reception signal with the second low band signal to mix the third mixing signal Acos ((ω _o t) -φ ₁ )) / 4 + Acos ((ω ₁ -2ω _m ) t-φ ₁ ) / 4) is output (d-2).

The beamforming signal generator 660 sums the second mixed signal and the third mixed signal (e) and extracts the low band signal (f). The signal extracted by the beamforming signal generator 660 is (Acos ((ω _o t) + φ ₁ + φ ₃ ) / 4 + Acos ((ω _o t) −φ ₁ ) / 4). Here, φ ₃ is set so that (φ ₂ = φ ₁ + φ ₃ ).

Here, the first phase difference φ ₁ is a phase difference considering the path difference and the frequency of the receiver and the beamforming point of the first band signal, and the third phase difference φ ₃ is the path of the receiver and beamforming point of the second band signal. The difference between the phase difference φ ₂ considering the difference and the frequency and the first phase difference φ ₁ can be set.

That is, the phase difference according to the first path is obtained as φ ₁ , and in the case of φ ₂ which is the phase difference according to the second path, the phase difference is referred to by using the phase lookup table according to the formula of (φ ₃ = φ ₂ -φ ₁ ). By storing the phase lookup table as a value, the amount of storage space required can be reduced.

FIG. 8 shows a broadband phase rotation circuit that is more easily implemented by replacing the BPF of FIG. 5 with an LPF and a subtractor.

Referring to FIG. 8 together with FIG. 3, the beam receiver according to the third embodiment of the present invention may include a first mixer 810, a first filter 820, a second filter 830, a second mixer 840, The third mixer 850 includes a beamforming signal generator 860 and a subtractor 870.

9 is a diagram illustrating a frequency band of a signal generated in the beam receiver according to the third embodiment of the present invention. Here, it is also assumed that the frequency fo of the received signal reflected from the object of the received signal is 2.5 MHz, and the modulation frequency fm of the oscillation signal used for signal mixing is 5 MHz.

9 and 8, a beam receiver according to a third embodiment of the present invention will be described.

The first mixer 810 has an oscillation signal cos (ω _m t) + having a predetermined modulation frequency fm and a first phase difference φ ₁ relative to the ultrasonic wave received signal Acos (ω _o t) reflected from the object. φ ₁ ) is mixed with the ultrasonic reception signal a to mix the first mixing signal Acos ((ω _o -ω _m ) t-φ ₁ ) / 2 + Acos ((ω _o + ω _m ) t + φ ₁ ) / Output 2) (b).

The first filter 820 extracts the first band signal Acos ((ω _o + ω _m ) t + φ ₁ ) / 2 from the first mixed signal, and the second filter 830 extracts the first mixed signal from the first mixed signal. The second band signal Acos ((ω _o -ω _m ) t-φ ₁ ) / 2 is extracted (c-1).

The subtractor 870 subtracts the second band signal from the first band signal to generate a subtracted signal (c-2). 8 is a diagram in which the BPF of FIG. 5 is replaced with an LPF and a subtractor, so the subtracted signal in FIG. 9 is similar to the waveform of the first band signal in FIG. 7.

Here, a low pass filter (LPF) may be used as the first filter 820 and the second filter 830, but the present invention is not limited thereto.

The second mixer 840 mixes the oscillation signal cos (ω _m t) -φ ₃ having a third phase difference φ ₃ with respect to the modulation frequency fm and the ultrasonic wave reception signal and mixes the first band signal with the second band signal. A mixing signal ((Acos ((ω _o t) + φ ₁ + φ ₃ ) / 4 + Acos ((ω ₁ + 2ω _m ) t + φ ₁ -φ ₃ ) / 4)) is output (d-2) The third mixer 850 mixes the oscillation signal cos (ω _m t) having the same phase as that of the modulation frequency fm and the ultrasonic reception signal with the second low band signal, thereby mixing the third mixing signal Acos ((ω _o t) -φ ₁ )) / 4 + Acos ((ω ₁ -2ω _m ) t-φ ₁ ) / 4) is output (d-1).

The beamforming signal generator 860 sums the second mixed signal and the third mixed signal (e) and extracts the low band signal (f). The signal extracted by the beamforming signal generator 860 is (Acos ((ω _o t) + φ ₁ + φ ₃ ) / 4 + Acos ((ω _o t) −φ ₁ ) / 4). Here, φ ₃ is set so that (φ ₂ = φ ₁ + φ ₃ ).

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

As described above, the present invention has an effect of improving image quality and realizing low power by performing phase rotation of the same magnitude for each frequency component of a received signal when beamforming using the received signal in an ultrasonic medical diagnostic apparatus. to be.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is filed with the Korean Patent Application No. 10-2011-0006461 filed in Korea on January 21, 2011 and the patent application No. 10-2011-0138527 filed in Korea on December 20, 2011. If priority is claimed under section (a) (35 USC § 119 (a)), all of that is incorporated by reference into this patent application. In addition, if this patent application claims priority to a country other than the United States for the same reason, all its contents are incorporated into this patent application by reference.

Claims

A first filter extracting a first band signal from the received signal reflected from the object;

A second filter extracting a second band signal from the received signal reflected from the object;

A first mixer for outputting a first mixing signal by mixing an oscillation signal having a predetermined modulation frequency and a first phase difference φ 1 with respect to the received signal with the first band signal;

A second mixer for outputting a second mixing signal by mixing the oscillation signal having the modulation frequency and a second phase difference (φ 2 ) with respect to the received signal with the second band signal;

A first low band filter extracting a low frequency band component from the first mixed signal to generate a first low band output;

A second low band filter extracting a low frequency band component from the second mixed signal to generate a second low band output;

A third mixer for mixing the oscillation signal having the same phase as the modulation frequency and the received signal with the first low band output to output a third mixing signal;

A fourth mixer outputting a fourth mixing signal by mixing the oscillation signal having the same phase as the modulation frequency and the received signal with the second low band output; And

A beamforming signal generator configured to generate a beamforming signal by adding the third mixed signal and the fourth mixed signal after low-band filtering and summing

Medical diagnostic apparatus comprising a.
The method of claim 1,

And the first filter and the second filter each use a band pass filter (BPF).
The method of claim 1,

The first phase difference φ 1 is a phase difference considering the path difference and the frequency of the receiver and the beamforming point of the first band signal, and the second phase difference φ 2 is the path difference between the receiver and the beamforming point of the second band signal. And a phase difference in consideration of frequency.
A first mixer for outputting a first mixed signal by mixing an oscillation signal having a predetermined modulation frequency and a first phase difference φ 1 with respect to the received signal reflected from the object with the received signal;

A first filter extracting a first band signal from the first mixed signal;

A second filter extracting a second band signal from the first mixed signal;

A second mixer for outputting a second mixing signal by mixing an oscillation signal having a modulation frequency and a third phase difference (φ 3 ) with respect to the received signal with the first band signal;

A third mixer for mixing the oscillation signal having the same phase as the modulation frequency and the received signal with the second low band signal to output a third mixing signal; And

A beamforming signal generator configured to sum the second mixed signal and the third mixed signal and extract a low band signal;

Medical diagnostic apparatus comprising a.
The method of claim 4, wherein

The first filter is a band pass filter (BPF), and the second filter is a low pass filter (LPF).
The method of claim 4, wherein

The first phase difference φ 1 is a phase difference considering the path difference and the frequency of the receiver and the beamforming point of the first band signal, and the third phase φ 3 is the path of the receiver and beamforming point of the second band signal. And a difference value between the phase difference considering the difference and the frequency and the first phase difference φ 1 .
A first mixer which receives a first phase oscillation signal having a first phase difference φ 1 with respect to a received signal reflected from an object from a first phase generator, mixes the received signal and outputs a first mixed signal. ;

A first filter extracting a first band signal from the first mixed signal;

A second filter extracting a second band signal from the first mixed signal;

A subtractor for generating a subtracted signal by subtracting the second band signal from the first band signal;

A second mixer for outputting a second mixing signal by mixing the oscillation signal having the modulation frequency and the third phase difference (φ 3 ) with respect to the received signal with the addition signal;

A third mixer for mixing the oscillation signal having the same phase as the modulation frequency and the received signal with the second band signal to output a third mixing signal; And

A beamforming signal generator configured to sum the second mixed signal and the third mixed signal and extract a low band signal;

Medical diagnostic apparatus comprising a.
The method of claim 7, wherein

And the first filter and the second filter each use a low pass filter (LPF).
The method of claim 7, wherein

The first phase difference φ 1 is a phase difference considering the path difference and the frequency of the receiver and the beamforming point of the first band signal, and the third phase φ 3 is the path of the receiver and beamforming point of the second band signal. And a difference value between the phase difference considering the difference and the frequency and the first phase difference φ 1 .