JP2878163B2 - Ultrasound Doppler diagnostic device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ultrasonic Doppler diagnostic apparatus, and more particularly to an ultrasonic Doppler diagnostic apparatus to which a two-frequency method or a two-period method for expanding a speed measurement range is applied.

[0002]

2. Description of the Related Art For example, Japanese Patent Publication No. 62-44494 discloses a conventional ultrasonic Doppler diagnostic apparatus. In such an apparatus, a received signal is subjected to quadrature detection and converted into a complex signal.
A complex operation (autocorrelation operation) is performed on the complex signal, and the speed of the in-vivo motion reflector (blood flow) is calculated from the autocorrelation operation result.

[0003] In such an ultrasonic Doppler method, the maximum measurable speed is defined as a range in which so-called aliasing does not occur. Therefore, as a method of expanding the maximum measurable velocity, a conventional two-frequency method (see Japanese Society of Ultrasound Medicine, May 1990, "High-speed blood flow measurement by two-frequency method") and a two-period method (for example, Fairness 3-23050
No.) has been proposed.

[0004] The former two-frequency method obtains an expanded velocity measurement range by using two kinds of received signals obtained by sequentially transmitting ultrasonic pulses of two kinds of frequencies. The two-period method uses two types of reception signals obtained by sequentially transmitting ultrasonic pulses at two types of transmission repetition periods to expand the speed measurement range as in the former case. Note that Japanese Patent Application Laid-Open No. H5-212032 discloses an ultrasonic Doppler diagnostic apparatus that uses both a general speed calculation and a speed calculation based on the above-described two-frequency method.

[0005]

However, in a device to which the conventional two-frequency method or two-period method is applied, in order to obtain a practical frame rate, it is necessary to estimate the speed of the motion reflector. The number of usable data could not be sufficiently secured, and thus the accuracy of speed estimation could not be further improved.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide an ultrasonic Doppler diagnostic apparatus to which a two-frequency method or a two-period method for expanding a speed measurement range is applied. Without reducing the rate,
It is to improve the speed estimation accuracy.

It is another object of the present invention to improve speed estimation accuracy while applying two-way simultaneous reception.

[0008]

In order to achieve the above-mentioned object, the present invention provides a method of transmitting and receiving a plurality of times for each beam direction, the plurality of times of transmitting and receiving being a plurality of first-half transmitting and receiving, and a plurality of subsequent transmitting and receiving. In the ultrasonic Doppler diagnostic apparatus divided into the latter half transmission and reception, in the first half transmission and reception in the nth beam direction, the first transmission frequency used in the (n-1) th second half transmission and reception is maintained and set, In the latter half of transmission, transmission control means for switching and setting a second transmission frequency different from the first transmission frequency, and performing a first complex operation on each reception signal obtained by each transmission and reception to obtain a first complex signal A first complex operation unit that smoothes a plurality of the first complex signals obtained by the latter half transmission / reception and the first half transmission / reception related to the same transmission frequency continuously over two adjacent beam directions; A second complex operation is performed by using a smoothing unit that obtains a smoothed signal, and the smoothed signal related to the first transmission frequency and the smoothed signal related to the second transmission frequency, to obtain a second complex signal. And a speed calculating means for obtaining a speed signal from the second complex signal.

According to the above configuration, in the ultrasonic Doppler processing based on the two-frequency method, in the first half transmission / reception in the n-th beam direction and the second half transmission / reception in the (n−1) th beam direction adjacent thereto, the same transmission frequency is used. Transmission is performed using the sound wave pulse, and the speed is calculated using a plurality of reception signals related to the same transmission frequency that are continuous over two adjacent beam directions. That is, since the number of received signals to be smoothed can be increased (for example, can be doubled) as compared with the conventional case, the speed estimation accuracy can be improved. In other words, the present invention reduces the frame rate by integrating and using received signals of the same frequency obtained in two adjacent beam directions while slightly sacrificing the spatial resolution (resolution in the scanning direction). Without increasing the number of data used in the speed calculation.

In a preferred aspect of the present invention, in order to perform two-way simultaneous reception, two systems each of the first complex operation means and the smoothing means are provided, and after the smoothed signals of each system are added. , Are input to the second complex operation means. By performing such two-way simultaneous reception, the number of data to be used can be further doubled to improve the speed estimation accuracy.

Further, the present invention provides an ultrasonic Doppler diagnostic system in which a plurality of transmissions and receptions are performed for each beam direction, and the plurality of transmissions and receptions are divided into a plurality of first half transmissions and a plurality of subsequent second half transmissions and receptions. In the apparatus, in the first half transmission / reception in the nth beam direction, the first in the (n−1) th second half transmission / reception
Transmission control means for maintaining and setting a transmission repetition cycle, and switching and setting a second transmission repetition cycle different from the first transmission repetition cycle in the latter half transmission / reception in the n-th beam direction; And a first complex operation means for performing a first complex operation on the first beam to obtain a first complex signal, and a second half transmission / reception and a first half transmission / reception relating to the same transmission repetition cycle continuously over two adjacent beams. A smoothing means for smoothing the plurality of first complex signals to obtain a smoothed signal, the smoothed signal according to the first transmission repetition cycle, and the smoothing signal according to the second transmission repetition cycle. A second complex operation unit that obtains a second complex signal by performing a second complex operation by using a second complex operation, and a speed operation unit that obtains a speed signal from the second complex signal.

According to the above configuration, in the ultrasonic Doppler processing based on the two-period method, similarly to the above, a plurality of transmission repetition cycles (transmission repetition frequencies) which are continuous over two adjacent beam directions and are continuous. The speed can be calculated using the received signal, and the accuracy of speed estimation can be improved.

In a preferred aspect of the present invention, in order to perform two-way simultaneous reception, the first complex operation means and the smoothing means are provided in two systems, respectively, and the smoothed signal of each system is added to the addition means. , And is input to the second complex operation means.

According to the present invention, for example, the number of data used for smoothing can be doubled as compared with the conventional case, and in that case, the dispersion of the speed estimation accuracy can be reduced to about 1 / √2 compared with the conventional case. According to the two-way simultaneous reception, the dispersion of the speed estimation accuracy can be reduced to about half of the conventional one.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a preferred embodiment of the present invention. FIG. 1 shows an ultrasonic Doppler diagnosis according to the present invention. It is a block diagram showing the whole composition of a device. This ultrasonic Doppler diagnostic apparatus is an apparatus to which the above-described two-frequency method or two-period method is applied.

In FIG. 1, a transmission control section 10 for controlling a transmission frequency or a transmission repetition cycle is composed of a timing signal generator 12 and a drive circuit 14. The timing signal generator 12 outputs a timing signal 200 serving as a reference for transmitting an ultrasonic pulse to the drive circuit 14 based on the basic clock generated by the oscillator 16. Further, the timing signal generator 12 outputs reference signals 204A and 204B for quadrature detection to a quadrature detector 18 described later. Drive circuit 14
Outputs a transmission signal to the probe 22 via the transmission / reception switch 20 based on the timing signal 200.
Thereby, ultrasonic waves are transmitted from the probe 22 to the living body,
The echo reflected by the motion reflector in the living body is received by the probe 22. The reception signal thus obtained is sent to the amplifier 24 via the transmission / reception switch 20, and the amplifier 24
Amplifies the received signal.

The reception signal output from the amplifier 24 is branched and one of the input signals is input to a detector 26. After detection is performed there, the reception signal is further amplified by an amplifier 28, and a DSC (digital scan) is performed. (Converter) 30. The DSC 30 has a built-in frame memory and has functions such as image synthesis and data interpolation.

On the other hand, the signal 20 branched by the amplifier 24
2, the reference signal 204 is output by the quadrature detector 18.
A, 204B is used to perform quadrature detection. By this quadrature detection, the received signal is converted into a complex signal 206 and sent to the speed calculator 32. Here, the complex signal 206 is composed of a signal 206A of a real part and a signal 206B of an imaginary part. The speed calculator 32 performs an autocorrelation calculation or the like based on the complex signal 206, finally obtains a speed signal 216, and converts the speed signal 216 into a DSC.
30.

In the DSC 30, a color Doppler image is combined with a black-and-white tomographic image, and the image information is displayed on a display unit 34.
And the display 34 displays such an ultrasonic image. The DSC 30 receives a transmission timing signal from the timing signal generator 12.

FIG. 2 shows a specific configuration of the quadrature detector 18 shown in FIG.

The received signal 202 is branched and input to the mixers 36A and 36B, respectively, and the reference signals 204A and
04B. The signals output from the mixers 36A and 36B are applied to low-pass filters (LPF) 38A and 38A.
After being input to B and extracting a signal in the baseband region, it is converted into a digital signal in A / D converters 40A and 40B and output as complex signals 206A and 206B.

FIG. 3 shows a specific configuration of the speed calculator 32 shown in FIG.

Complex signal 206 output from quadrature detector 206
A and 206B are first a high-pass filter (HPF) 42
Where clutter due to echoes such as the heart wall is removed. That is, the HPF 42 functions as a clutter removing filter, and clears an image by removing echo components such as a heart wall which is a strong reflector. Specifically, this HPF 42
Are delay lines 44A and 44B and adders 46A and 4
6B, and the reception signal for one ultrasonic beam is delayed in the delay lines 44A and 44B.
That is, the reception signal is delayed by the time corresponding to the transmission repetition period of the ultrasonic pulse.

The signals 208A output from the HPF 42,
208B is then input to the first complex operation unit 48, where a complex operation as an autocorrelation operation is executed. The first complex operation unit 48 includes the delay lines 50A and 50B and the multiplier 5
2A, 52B, 52C, 52D and adders 54A, 54
B. Delay line 50A,
In 50B, the complex signal is delayed by a time corresponding to the transmission repetition period.

The complex signals 210A and 210B output from the first complex operation unit 48 are then input to the integrator 56,
A plurality of complex signals are integrated. That is, the integrator 56 includes the delay lines 58A and 58B and the adder 60.
A, 60B, and a plurality of complex signals acquired in the same beam direction are added to improve the S / N ratio by smoothing.

The signals 212A, 212A,
212B is then input to the second complex operation unit 62. The second complex operation unit 62 is provided to extend the measurable speed range.
A, 64B and multipliers 66A, 66B, 66C, 66D
And adders 68A and 68B. That is, this second complex operation unit 62
The speed that can be measured is increased by performing the second complex operation based on the frequency method or the two-period method. The signals 214A, 214 output from the second complex operation unit 62
14B is then input to the speed calculation circuit 70, which calculates the angle of the moving body by calculating the argument and outputs a speed signal 216. Here, the speed calculation circuit 70
Is composed of a circuit for calculating an arc tangent.

The configurations shown in FIGS. 1, 2 and 3 are basically the same as those of the conventional ultrasonic Doppler diagnostic apparatus to which the two-frequency method or the two-period method is applied. The ultrasonic Doppler diagnostic apparatus according to the above is characterized in that the transmission frequency or the pattern of the transmission repetition period is different from the conventional one as described below.

FIG. 4 shows an example of a conventional two-frequency method in an ultrasonic Doppler diagnostic apparatus constituted by the components shown in FIGS. In FIG. 4, (a) shows the address (number of the beam direction) of the ultrasonic beam, and (b)
3 shows the timing signal 200 output from the timing signal generator 12 shown in FIG. 1, (c) shows the frequency of the ultrasonic pulse, and (d) shows the signals 208A and 208A output from the HPF 42 shown in FIG. 208B, and (e) shows the signal 21 output from the first complex operation unit 48 shown in FIG.
0A and 210B, (f) shows signals 212A and 212B output from the integrator 56, and (g) shows signals 214A and 214B output from the second complex operation unit 62. 4 to 7, (a) to (g)
And the corresponding relationship between the signals is the same in each figure.

In the conventional two-frequency method shown in FIG. 4, for example, 12 transmissions (transmission / reception) are performed at each beam address, and in the first half transmission / reception within each beam address, for example, six transmissions are performed at the frequency f1. In the latter half transmission and reception, six transmissions are performed at the frequency f2. This is the same for each beam address. When such transmission is performed, as shown in FIG. 3D, the data of one ultrasonic beam is lost due to the presence of the delay lines 44A and 44B shown in FIG. Five data were acquired, and A
Five data 21 to A25 are acquired. And
As shown in (e), when such a signal is input to the first complex operation unit 48, the delay line 5 included therein is input.
One data is lost due to 0A and 50B, and the first speed calculator 48 outputs four data B11 to B14 and B21 to B21 in the first half and the second half, respectively.
24 will be output. Next, in the integrator 56, the four data are respectively added by the adding operation to obtain data C11 and C21.
C21 is input to the second complex operation unit 62, where the second complex operation is executed, and a complex signal D is obtained as an output thereof. The complex signal D is the complex signal 21 in FIG.
4A, 214B, which is the speed calculation circuit 70
And speed information is calculated.

On the other hand, in the two-frequency method according to the present invention, FIG.
As shown in (c), in the first half transmission / reception of the nth beam address, the first transmission frequency used in the (n-1) th second half transmission / reception is maintained and set, and in the second half transmission / reception in the nth beam direction, A second transmission frequency different from the first transmission frequency is switched and set. For example, in the second frame, the frequency f1 is used in the first half transmission / reception, and the frequency f2 is used in the second half transmission / reception, but the first half transmission / reception of the next third frame is the same as the second half transmission / reception of the previous frame. The frequency f2 is used, and the frequency f1 is used in the latter half of transmission and reception. By making the frequencies of the second half transmission and the first half transmission and reception coincide between the adjacent beam directions in this manner, the following advantages can be obtained.

That is, in the present embodiment, the HPF 42 shown in FIG. 3 obtains five data in each of the first half transmission and the second half transmission and reception as in the conventional case shown in FIG. 4 (see FIG. 5D). Although four data are obtained in each section in the one-complex operation unit 48 as in the conventional case (see FIG. 5E), the integrator 56 differs from the conventional example shown in FIG. , And eight data (see FIG. 5F). That is, since the transmission frequency is maintained between adjacent beams, the number of data to be added in the integrator 56 can be doubled as compared with the conventional case, and as a result, the S / N ratio can be improved. Of course, such processing will result in a slight decrease in spatial resolution,
In the processing of Doppler signals, it is extremely important to improve the S / N ratio, and according to the present invention, useful signal processing can be achieved in the processing of such ultrasonic Doppler signals. The above-described signal processing is performed in the second half transmission and reception of the first beam address and the first half transmission and reception of the second beam address as shown in FIG. The second complex operation unit 62 performs the transmission and reception of the first half of the beam address of FIG.
The second complex operation is executed using the outputs C11 and C21 of the integrator 56 which are the result of adding the eight data as shown in FIG. Then, data D is output as the operation result.

FIG. 6 shows a transmission / reception system when the conventional two-period method is applied to the ultrasonic Doppler diagnostic apparatus shown in FIGS. As shown in FIG. 6C, in each beam address, transmission is performed, for example, six times in the transmission repetition period T1 of the ultrasonic pulse in the first half, and, for example, six in the transmission repetition period T2 in the second half.
Times have been sent. This is the same for each beam address. In such a conventional two-period method, FIG.
As shown in (d), five data A11 to A15 are output from the HPF 42 in the first half transmission and reception, and five data A21 to A25 are output in the second half. Then, as shown in FIG. 6E, the first complex operation unit 48 outputs four data B11 to B14 in the first half, and outputs four data B21 to B24 in the second half.
Then, as shown in (f), the integrator 56 adds the four data in each of the first half and the second half,
The addition results C11 and C21 are used as the second complex operation unit 6
2, where the second complex operation is executed, and D11 is output as the result of the complex operation.

FIG. 7 shows a transmission / reception system according to the two-period method according to the present invention.

In the transmission / reception method shown in FIG. 7, in the first half transmission / reception in the n-th beam direction, the first transmission repetition cycle used in the (n-1) -th second half transmission / reception is maintained and set. In transmission and reception, a second transmission repetition cycle different from the first transmission repetition cycle is set. Specifically, as shown in FIG. 7, for example, at the second beam address, for example, six transmissions are performed in the transmission repetition period T1 in the first half transmission and reception, and in the latter half, for example, six transmissions are performed in the transmission repetition period T2. A transmission is taking place. In the beam addresses before and after that, T2 is set as the transmission repetition cycle in the first half transmission and reception, and T1 is set as the transmission repetition cycle in the second half transmission and reception. That is, the same transmission repetition frequency is set for the adjacent second half transmission and first half transmission and reception.

According to such transmission / reception, as shown in FIG. 7 (f), the integrator 56 adds eight data existing over adjacent beam addresses, and from the comparison with FIG. As is apparent, the number of data to be added can be doubled as compared with the conventional case. Integrator 56
Are subjected to a complex operation in the second complex operation unit 62 and the addition results C11 and C21 output from the second complex operation unit 6
2 outputs data D which is the operation result.

As described above, according to the ultrasonic Doppler diagnostic apparatus to which the two-frequency method or the two-period method according to the present invention is applied, the respective transmission frequencies of the second half transmission and the first half transmission between adjacent beam addresses are adjacent. Alternatively, the integrator 56 is made continuous by making the transmission repetition cycle the same.
Can increase the number of data to be added as compared with the related art, and as a result, the speed estimation accuracy can be improved.

The switching of the transmission frequency or the switching of the transmission repetition period is performed by the transmission control unit 10 shown in FIG. 1, and the delay amount of each delay line in the speed calculator 32 depends on the transmission / reception system to be applied. Is set appropriately. For example, when the two-frequency method shown in FIG. 5 is applied, the reception signal is delayed by the time T in the delay lines 44A and 44B, where T is the time for one beam, and the delay lines 50A and 50A are used. 50
Also in B, the delay is performed for the time T. This is the same for the delay lines 58A and 58B.
The delay is performed only for the time. Delay line 6
In 4A and 64B, when the two-frequency method is applied, 12
The delay is performed for the time of × T. On the other hand, when the two-period method is applied, the delay lines 44A and 44B and the delay lines 50A and 50A are synchronized with the transmission repetition period.
0B and the delay lines 58A and 58B are respectively T1
Alternatively, the received signal is delayed for the time T2. In the delay lines 64A and 64B, delay is performed for a time of 12 × T1 or 12 × T2.

Next, another embodiment of the ultrasonic Doppler diagnostic apparatus according to the present invention will be described. FIG. 8A shows a normal transmission / reception method. In FIG. 8A, the transmission beam and the reception beam match. In FIG. 8B,
Two reception beams are set for one transmission beam. For example, assuming that the angle between the transmission beams is θ, the angle between the transmission beam and the reception beam is θ / 4, for example.

FIG. 9 shows the overall configuration of an ultrasonic Doppler diagnostic apparatus to which two-way simultaneous reception as shown in FIG. 8B is applied. The same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 9, two reception processing systems are provided to realize the two-way simultaneous reception described above. That is, for one of the reception signals output from the transmission / reception switch 20, the amplifier 24-1, the detector 26-1, and the amplifier 2
8-1 is provided, and an amplifier 2 is provided for the other received signal.
4-2, a detector 26-2, and an amplifier 28-2 are provided. Further, the received signal 220A output from the amplifier 24-1 is input to one quadrature detector 18-1, and the received signal 220B output from the amplifier 24-2 is input to the other quadrature detector 18-2. Have been. The complex signals 222A and 222B from the quadrature detector 18-1 are input to the speed calculator 100, and the complex signals 224A and 224B output from the quadrature detector 18-2 are also input to the speed calculator 100. .

FIG. 10 shows a specific configuration of the speed calculator 100. In this speed calculator 100,
To process the complex signals 222A and 222B, HPF
42-1, the first complex operation unit 48-1, and the integrator 56-
1 for processing the complex signals 224A and 224B, and the HPF 42-2 and the first complex operation unit 48-
2 and an integrator 56-2. FIG.
The specific configuration of each circuit shown in FIG. 0 is the same as that shown in FIG. 3, but in FIG. 10, two signal processing systems are provided.

Signal 234 output from integrator 56-1
A and 234B are input to the adder 102, and similarly, the signals 236A and 236B output from the integrator 56-2.
Are also input to the adder 102. Then, in the adder 102, the signals 234A and 2
36A, and the addition circuit 106 outputs the signal 23
4B and 236B are added. The signals 238A and 238B, which are the addition results, are input to the second complex operation unit 62.

FIG. 11 shows a transmission / reception system when the two-frequency method is applied to two-way simultaneous reception in the circuit configurations shown in FIGS. In FIG.
(A1) shows a beam address for one of the received signals, (b1) shows a transmission timing signal, and (c1)
1) indicates the transmission frequency, (d1) indicates the output of the HPF 42-1 and (e1) indicates the output of the first complex operation unit 48-1. Similarly, (a2) indicates a beam address for the other receive beam, (b2) indicates a transmission timing signal, (c2) indicates a transmission frequency,
(D2) shows the output of the HPF 42-2, and (e2) shows the output of the first complex operation unit 48-2. And
(F) shows the output of the adder 102 that adds the outputs of the integrators 56-1 and 56-2, and (g) shows the output of the second complex operation unit 62.

As shown in FIG. 11, by applying the two-frequency method according to the present invention in two-way simultaneous reception, that is, by using the same transmission frequency in the adjacent second half transmission and the first half transmission, two In each of the reception processing systems, the number of data to be added in the integrator 56 can be doubled, and by adding them in the adder 102, the number of data added as a result can be quadrupled as compared with the conventional case. it can. Therefore, the speed estimation accuracy can be improved as compared with the related art.

Of course, the two-period method can be applied to the two-way simultaneous reception.
Is shown in The correspondence between (a) to (g) and each signal is the same as that shown in FIG.

As shown in FIG. 12, the number of data to be added can be quadrupled in the two-period method as well as in the two-period method. Can be improved.

As described above, according to the above-described ultrasonic Doppler diagnostic apparatus to which the two-frequency method or the two-period method according to the present invention is applied, the number of data to be added can be doubled as compared with the conventional one. 1 / の
About two, and two-way simultaneous reception according to the present invention.
If a transmission / reception method using the frequency method or the two-period method is applied, it is possible to reduce the variation of the speed calculation result to about 1/2.

In this embodiment, since data addition is performed over two beams, data may be displayed between two transmission / reception beams when an actual ultrasonic image is formed.

[0049]

As described above, according to the present invention,
In an ultrasonic Doppler diagnostic apparatus to which the two-frequency method or the two-period method for expanding the speed measurement range is applied, the accuracy of speed estimation can be improved without lowering the frame rate. In addition, if the two-way simultaneous reception is applied together with the present invention, the speed estimation accuracy can be further improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of an ultrasonic Doppler diagnostic apparatus according to the present invention.

FIG. 2 is a diagram showing a specific circuit configuration of a quadrature detector.

FIG. 3 is a diagram showing a specific circuit configuration of a speed calculator.

FIG. 4 is a diagram showing a transmission / reception method in a conventional two-frequency method.

FIG. 5 is a diagram showing a transmission / reception method in a two-frequency method according to the present invention.

FIG. 6 is a diagram showing a transmission / reception method in a conventional two-period method.

FIG. 7 is a diagram showing a transmission / reception method in a two-period method according to the present invention.

FIG. 8 is a diagram showing normal transmission and reception and two-way simultaneous reception.

FIG. 9 is a block diagram showing an overall configuration of an ultrasonic Doppler diagnostic apparatus to which two-way simultaneous reception is applied.

FIG. 10 is a diagram showing a specific circuit configuration of a speed calculator for performing two-way simultaneous reception.

FIG. 11 is a diagram illustrating a transmission / reception method when a two-frequency method is applied to two-way simultaneous reception.

FIG. 12 is a diagram illustrating a transmission / reception method when a two-period method is applied to two-way simultaneous reception.

[Explanation of symbols]

10 transmission control unit, 18 quadrature detector, 32 speed calculator, 42 high-pass filter, 48 first complex calculator,
56 integrator, 62 second complex operation unit, 70 speed operation circuit.

Claims (4)

(57) [Claims] 1. An ultrasonic Doppler diagnostic apparatus in which transmission and reception are performed a plurality of times for each beam direction, and the plurality of transmissions and receptions are divided into a plurality of first-half transmissions and a plurality of subsequent second-half transmissions. In the first half transmission / reception in the beam direction, the first transmission frequency used in the (n−1) th second half transmission / reception is maintained and set, and in the second half transmission / reception in the nth beam direction, a second transmission frequency different from the first transmission frequency is set. Transmission control means for switching and setting; first complex operation means for performing a first complex operation on each reception signal obtained by each of the transmission and reception to obtain a first complex signal; and straddling two adjacent beam directions. Smoothing means for performing a smoothing process on a plurality of the first complex signals obtained by the second half transmission and reception and the first half transmission and reception related to the same continuous transmission frequency to obtain a smoothed signal; A second complex operation unit that performs a second complex operation by using the smoothed signal and the smoothed signal related to the second transmission frequency to obtain a second complex signal; and a speed signal from the second complex signal. An ultrasonic Doppler diagnostic apparatus, comprising: a speed calculating unit that obtains: 2. The apparatus according to claim 1, wherein the first complex operation means and the smoothing means are provided in two systems for simultaneous two-way reception, and the smoothed signals of each system are added. The ultrasonic Doppler diagnostic apparatus is input to the second complex operation unit after the operation. 3. An ultrasonic Doppler diagnostic apparatus in which a plurality of transmissions and receptions are performed for each beam direction, and the plurality of transmissions and receptions are divided into a plurality of first half transmissions and a plurality of subsequent second half transmissions and receptions. In the first half transmission and reception in the nth beam direction, the first transmission repetition cycle in the (n-1) th second half transmission and reception is maintained, and in the second half transmission and reception in the nth beam direction, a second transmission repetition cycle different from the first transmission repetition cycle Transmission control means for switching and setting, a first complex operation means for performing a first complex operation on each received signal obtained by each of the transmission and reception to obtain a first complex signal, and a straddle extending over two adjacent beam directions. Smoothing means for performing a smoothing process on the plurality of first complex signals obtained by the latter half transmission / reception and the first half transmission / reception related to the same continuous transmission repetition cycle to obtain a smoothed signal. A second complex operation unit that performs a second complex operation using the smoothed signal according to the first transmission repetition cycle and the smoothed signal according to the second transmission repetition cycle to obtain a second complex signal; An ultrasonic Doppler diagnostic apparatus, comprising: a speed calculating unit that obtains a speed signal from the second complex signal. 4. The apparatus according to claim 3, wherein said first complex operation means and said smoothing means are provided respectively in two systems in order to perform two-way simultaneous reception, and said smoothed signal of each system is added by said addition means. After being added by
An ultrasonic Doppler diagnostic apparatus, which is input to the second complex operation means.