JP2004209111A - Ultrasonograph - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease the capacity of a memory for storing transmission delay time. <P>SOLUTION: The ultrasonograph has counters 34a to 34n in which delay count values, corresponding to vibration elements 12a to 12n and providing transmission delay time of each vibration element, are set. The counters 34a to 34n count a clock signal 46 that is output from a first frequency divider 32, and output a counter output signal 48 when a counted value matches a delay count value. A CPU 36 calculates the reference delay count value of each vibration element, which corresponds to the reference frequency. Any delay count values corresponding to selected frequencies besides the reference frequency are converted from the standard delay count value using a conversion table 74. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ultrasonic diagnostic apparatus, and more particularly, to an ultrasonic diagnostic apparatus for setting a transmission delay time.
[0002]
[Prior art]
In an ultrasonic diagnostic apparatus that transmits an ultrasonic wave to a living tissue, processes the echo signal and displays the echo signal as, for example, a tomographic image, Doppler information, etc., an ultrasonic beam is formed by an ultrasonic vibrator including a plurality of vibrating elements. The ultrasonic beam is electronically scanned. In order to perform this electronic scanning, a transmission signal delayed by a predetermined amount is supplied to each vibration element.
[0003]
FIG. 4 is a block diagram of the transmission unit 10 of the ultrasonic diagnostic apparatus. The transmission unit 10 supplies a transmission drive signal having a transmission delay time corresponding to each of the plurality of vibration elements 12a to 12n of the ultrasonic transducer 11 under the control of a transmission / reception control unit (not shown).
[0004]
In FIG. 4, a first frequency divider 32 has a function of generating a plurality of frequencies by changing a frequency division ratio, and a clock generator 30 according to a frequency division ratio selected under the control of a CPU 36 described later. Is divided and output as a clock signal 46 to each of the counters 34a to 34n. For example, when the output of the clock generator 30 is 120 MHz, 40 MHz, 30 MHz, 24 MHz, or the like can be generated as the frequency of the clock signal 46.
[0005]
Each of the counters 34 a to 34 n is a counter for counting the clock signal 46 input from the first frequency divider 32, and includes a reset terminal for resetting the count value by the initialization signal 42, and a delay count value for defining the transmission delay time. Are set, and delay count value setting sections 40a to 40n. The delay count values corresponding to the respective vibrating elements 12a to 12n are output from the data holding unit 38 and set in the delay count value setting units 40a to 40n under the control of the CPU 36 described later. Each of the counters 34a to 34n starts counting the clock signal 46 after the input of the initialization signal 42, and outputs a counter output signal 48 when the count value matches the set delay count value.
[0006]
The second frequency divider 58 is a circuit that divides the frequency of the counter output signal 48 to obtain a desired transmission frequency. The amplifier 60 is a circuit that amplifies the frequency-divided signal and supplies it to each of the vibrating elements 12a to 12n as a transmission drive signal. By using the second frequency divider 58, the frequency of the clock signal 46 can be increased correspondingly, and the resolution of the delay count value can be increased.
[0007]
The CPU 36 has a function as calculation means for calculating each delay count value that defines the transmission delay time of each of the vibration elements 12a to 12n. That is, for each frequency of the clock signal 46 that can be generated by the first frequency divider 32, each delay count value corresponding to each of the vibrating elements 12 a to 12 n is calculated and output to the data holding unit 38.
[0008]
The data holding unit 38 stores and holds all calculated delay count values. For example, each delay count value calculated corresponding to each of the vibration elements 12a to 12n is stored and held for each frequency of the clock signal 46. Therefore, if the frequencies that can be generated by the first frequency divider 32 are N types, such as 40 MHz, 30 MHz, and 24 MHz, the CPU 36 calculates the delay count value for each of the vibrating elements 12 a to 12 n corresponding to the N types of frequencies. The calculation result is stored in the data holding unit 38.
[0009]
Further, the CPU 36 is connected to the first frequency divider 32, the second frequency divider 58, and the data holding unit 38, and according to the transmission frequency selected by the transmission frequency selecting means (not shown), the first frequency divider 32 , A function of instructing a frequency division ratio of the second frequency divider 58 and an instruction of an output to the delay count value setting units 40a to 40n of the data holding unit 38. The transmission frequency can be selected by a user's input, or may be automatically selected based on a preset criterion, for example, a criterion in accordance with the function switching order of the ultrasonic diagnostic apparatus.
[0010]
In the above configuration of the transmission unit of the conventional ultrasonic diagnostic apparatus, a transmission drive signal having a transmission delay time corresponding to each of the vibration elements 12a to 12n is supplied as follows. For example, when the transmission frequency of the ultrasonic wave is selected to be 5 MHz by a transmission frequency selection unit (not shown), the CPU 36 gives an instruction to the first frequency divider 32 to generate the clock signal 46 having a frequency of 40 MHz. , An instruction of １ ／ frequency division is given to the second frequency divider 58. Further, the data holding unit 38 is instructed to output and set each delay count value corresponding to the frequency of 40 MHz to each of the delay count value setting units 40a to 40n. Thus, each of the counters 34a to 34n counts the clock signal 46 of 40 MHz, and when the count value matches the delay count value corresponding to 40 MHz, the counter output signals 48a to 48n are output. Each output signal is frequency-divided to 5 MHz by the second frequency divider 58, amplified by the amplifier 60, and supplied to each of the vibrating elements 12a to 12n with a 5-MHz transmission drive signal having a corresponding transmission delay time. .
[0011]
Similarly, when another transmission frequency, for example, a transmission frequency of 3.75 MHz is selected, an instruction of an appropriate frequency division ratio is given to the first frequency divider 32 and the second frequency divider 58, and the data is also transmitted. The holding unit 38 is instructed to output each delay count value corresponding to the frequency of the clock signal to each of the delay count value setting units 40a to 40n.
[0012]
[Problems to be solved by the invention]
Due to the function of the ultrasonic diagnostic apparatus, if the calculation of the delay count corresponding to each vibration element required for electronic scanning is small, the CPU is required to match the electronic scanning speed without providing a data holding unit. Each delay count can be calculated. In addition, when the calculation of each delay count required for electronic scanning is large and it is difficult for the CPU to calculate each delay count required in accordance with the speed of electronic scanning, each delay count required in advance is calculated. By calculating, storing the data in the data holding unit, and reading out the data as needed, it is possible to obtain each required delay count in accordance with the speed of electronic scanning.
[0013]
Incidentally, the ultrasonic diagnostic apparatus has a plurality of functions such as a Doppler mode and a color Doppler mode in which a blood flow velocity or the like can be measured using the Doppler effect, in addition to a B mode in which a tomographic image of a living tissue can be observed. Things are increasing. Diagnosis of the living tissue is performed while switching these functions. In this case, since the transmission frequency is selected according to each diagnostic function, it is necessary to switch the transmission frequency in accordance with the switching of the function, and to switch the setting of the delay count value in real time according to the switched transmission frequency. .
[0014]
As described above, in order to switch each delay count value in real time, it is necessary to store all the delay count values used for each function to be switched in the data holding unit and quickly read out the data in accordance with the switching. .
[0015]
However, transmission delay time data necessary for electronic scanning is very large. For example, in the case of electronic sector scanning, a transmission delay time for each vibration element is required for each scanning angle (beam address) of electronic scanning, and further for each focus position (focus number) to change the focus position. become. Further, if the configuration of the vibration element of the ultrasonic transducer is different, the transmission delay time of each vibration element is also different. Then, it is necessary to prepare data on the case where the highest resolution is required among the functions that are assumed to be switched. For example, as for the beam address, it is necessary to prepare data of each transmission delay time for all beam addresses of the finest scanning angle pitch, and the same applies to the focus position, the number of vibrating elements, and the like.
[0016]
In addition, even if the transmission delay time is the same, if the transmission frequency is different, the corresponding delay count value will be different, and the data amount of the delay count value to be stored in the data holding unit will be N times as large as N transmission frequencies. To increase. Therefore, the memory capacity of the data holding unit increases, and a large-capacity memory is required. Further, as the capacity of the memory of the data holding unit increases, the data reading time increases, and the delay count value is not quickly switched.
[0017]
An object of the present invention is to solve the problem of the related art and to provide an ultrasonic diagnostic apparatus capable of reducing the capacity of a memory for storing a transmission delay time. Another object is to provide an ultrasonic diagnostic apparatus that can quickly set a transmission delay time.
[0018]
[Means for Solving the Problems]
To achieve the above object, the ultrasonic diagnostic apparatus according to the present invention counts a selected clock selected from a plurality of clocks of different frequencies, and is set to determine the count value and the transmission delay time. A control circuit that outputs the selected clock when the delay count value matches, generates a transmission pulse of a transmission frequency based on the output, and a transmission drive pulse that is supplied to an ultrasonic transducer based on the transmission pulse. A transmission circuit that generates a clock signal, a calculating unit that replaces a transmission delay time with a count value of a clock of a reference frequency, and a time indicated by the reference count value as a count value of the selected clock. Means for setting the converted count value as a delay count value for determining the transmission delay time. And butterflies.
[0019]
Further, the ultrasonic diagnostic apparatus according to the present invention, a plurality of vibrating elements for transmitting and receiving ultrasonic waves, and for each of the vibrating elements, count a selected clock selected from a plurality of clocks of different frequencies, the When the count value matches each delay count value set for determining each transmission delay time corresponding to each vibration element, the selected clock is output, and the transmission frequency is determined based on each output. In an ultrasonic diagnostic apparatus including a transmission unit having: a control circuit that generates each transmission pulse; and a transmission circuit that generates each transmission drive pulse to be supplied to each of the vibration elements based on each transmission pulse. Calculating means for replacing each transmission delay time with a reference frequency clock count value for each element; and a time indicated by the reference frequency clock count value for each vibrating element. The terms of the count value of the selected clock, characterized in that it comprises means for setting the converted count value as the delay count value for determining the transmission delay time, the.
[0020]
With this configuration, the delay count value corresponding to a frequency other than the reference frequency can be converted from the count value of the clock of the reference frequency by using a conversion unit that performs linear conversion such as frequency multiplication or frequency division. Only the count value corresponding to the reference frequency needs to be calculated and stored. Therefore, the capacity of the memory relating to the transmission delay time can be reduced.
[0021]
The reference frequency may be any one of the plurality of frequencies, and another frequency may be defined as the reference frequency.
[0022]
Further, the means for converting to the delay count value is a conversion table between a count value of the clock of the reference frequency and a delay count value corresponding to each of the plurality of clocks of different frequencies. And a count value of the clock of the reference frequency, and a memory that outputs a delay count value corresponding to the selected clock. The difference of the delay count value corresponding to the same transmission delay time depending on the clock frequency is only the frequency ratio determined from the frequency multiplication or frequency division relationship. Therefore, a conversion table or a memory for converting the ratio between the reference frequency and the selected frequency corresponding to the count value of the clock of the reference frequency can be used as the means for converting into the delay count value. For example, a semiconductor memory such as a RAM can be used.
[0023]
Further, it is preferable that the number of bits representing the count value of the clock of the reference frequency is larger than the number of bits representing the delay count value corresponding to the selected clock. For example, the number of bits representing the count value of the clock of the reference frequency can be used by increasing the number of bits representing the delay count value corresponding to the selected frequency by m bits. m can be selected from one or more integers. Thus, even when the ratio between the reference frequency and the selected frequency cannot be divided, the conversion of the clock count value of the reference frequency to the delay count value corresponding to the selected frequency can be performed more accurately.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of the transmission unit 70 of the ultrasonic diagnostic apparatus. Elements common to those in FIG. 4 are denoted by the same reference numerals, and description thereof is omitted.
[0025]
In FIG. 1, a first frequency divider 32 is a frequency divider having a function of dividing the output of the clock generator 30 according to a frequency division ratio selected under the control of the CPU 36 and outputting a clock of a selected frequency. is there. The clock of the selected frequency is input as a clock signal 46 to each of the counters 34a to 34n. For example, when the output of the clock generator 30 is 120 MHz, the selected frequency is selected from a plurality of frequencies such as 40 MHz, 30 MHz, and 24 MHz that can be divided from 120 MHz.
[0026]
Each of the counters 34 a to 34 n is a counter for counting the clock signal 46 input from the first frequency divider 32, and includes a reset terminal for resetting the count value by the initialization signal 42, and a delay count value for defining the transmission delay time. Are set, and delay count value setting sections 40a to 40n. The delay count values corresponding to the respective vibration elements 12a to 12n are output from the conversion table 74 and set in the delay count value setting units 40a to 40n under the control of the CPU 36 described later. Each of the counters 34a to 34n starts counting the clock signal 46 after the input of the initialization signal 42, and outputs a counter output signal 48 when the count value matches the set delay count value.
[0027]
The second frequency divider 58 is a circuit that divides the counter output signal 48 to obtain the desired transmission frequency, and the amplifier 60 amplifies the frequency-divided signal and supplies it as a transmission drive signal to each of the vibrating elements 12a to 12n. Circuit.
[0028]
The CPU 36 has a function as calculating means for calculating a reference delay count value corresponding to the reference frequency. Here, the reference delay count value indicates a transmission delay time as a count value of a clock having a reference frequency. The reference frequency may be determined by selecting any one of a plurality of frequencies that can be generated by the first frequency divider 32, or another frequency may be determined as the reference frequency. Since the reference frequency is a reference for conversion in a conversion table described later, the higher the frequency, the more accurate the conversion. For example, 40 MHz can be determined as the reference frequency. The reference delay count value is calculated for each of the vibrating elements 12a to 12n, and the calculation result is output to the reference delay count value holding memory 72 and stored. The reference delay count value holding memory 72 outputs each stored reference delay count value to the conversion table 74 when converting the conversion table 74 under the control of the CPU 36.
[0029]
The CPU 36 is connected to the first frequency divider 32, the second frequency divider 58, and the conversion table 74, and according to the transmission frequency selected by the transmission frequency selector (not shown), the first frequency divider 32, It has a function of instructing the frequency division ratio of the second frequency divider 58 and instructing which conversion to use in the conversion table 74. The transmission frequency can be selected by a user's input, or may be automatically selected based on a preset criterion, for example, a criterion in accordance with the function switching order of the ultrasonic diagnostic apparatus.
[0030]
The conversion table 74 has a function as conversion means for converting the reference delay count value into a delay count value corresponding to the selected frequency. That is, under the control of the CPU 36, each reference delay count value output from the reference delay count value holding memory 72 is converted into each delay count value corresponding to the selected frequency, and the converted delay count values are corresponded. Output to the delay count value setting units 40a to 40n of the respective counters. When the selected frequency is selected to be the same frequency as the reference frequency, the conversion table 74 does not perform conversion, and outputs the reference delay count value as it is to each of the delay count value setting units 40a to 40n of each counter and sets it.
[0031]
Even for the same transmission delay time, the delay count value differs depending on the clock frequency, but the difference is simply the frequency ratio based on the frequency multiplication or frequency division relationship, so that the conversion can be easily performed using linear conversion. For example, in the above example, assuming that the reference frequency is 40 MHz and the selected frequency is selected from 30 MHz and 24 MHz, 30/40 is used as a conversion constant for conversion between 40 MHz and 30 MHz, and between 40 MHz and 24 MHz. For the conversion, 24/40 is used as a conversion constant. The specific contents of the conversion table 74 will be described later.
[0032]
In the above configuration of the transmission unit of the ultrasonic diagnostic apparatus according to the embodiment of the present invention, a transmission drive signal having a transmission delay time corresponding to each of the vibration elements 12a to 12n is supplied as follows. For example, when the transmission frequency of the ultrasonic wave is selected to be 5 MHz by a transmission frequency selection unit (not shown), the CPU 36 gives an instruction to the first frequency divider 32 to generate the clock signal 46 having a frequency of 40 MHz. , An instruction of １ ／ frequency division is given to the second frequency divider 58. If the reference frequency is 40 MHz, the selected frequency is the same as the reference frequency. In this case, the conversion table 74 outputs the output of the reference delay count value holding memory 72 without conversion to each of the counters 34a to 34n. An instruction to set the delay count value setting units 40a to 40n is issued. Thus, each of the counters 34a to 34n counts the clock signal 46 of 40 MHz, and when the count value matches the delay count value corresponding to 40 MHz, the counter output signals 48a to 48n are output. Each output signal is frequency-divided to 5 MHz by the second frequency divider 58, amplified by the amplifier 60, and supplied to each of the vibrating elements 12a to 12n with a 5-MHz transmission drive signal having a corresponding transmission delay time. You.
[0033]
Next, when the function of the ultrasonic diagnostic apparatus is switched and the transmission frequency needs to be 3.75 MHz, the CPU 36 gives an instruction to the first frequency divider 32 to generate a clock signal 46 having a frequency of 30 MHz. Then, an instruction of １ ／ frequency division is given to the second frequency divider 58. Further, the conversion table 74 is instructed to convert 40 MHz to 30 MHz. The conversion table 74 converts each reference delay count value output from the reference delay count value holding memory 72 into a delay count value corresponding to 30 MHz by linear conversion of 40 MHz to 30 MHz, and converts the converted value to each of the counters 34a to 34MHz. 34n and outputs them to the delay count value setting units 40a to 40n. In this way, the counters 34a to 34n count the clock signal 46 of 30 MHz, and when the count value matches the delay count value corresponding to 30 MHz, the counter output signals 48a to 48n are output. Each output signal is frequency-divided to 3.75 MHz by the second frequency divider 58 and amplified by the amplifier 60. Each of the vibrating elements 12a to 12n has a 3.75 MHz transmission drive having a corresponding transmission delay time. A signal is provided.
[0034]
Similarly, when another transmission frequency is selected, an instruction of the division ratio is given to the first frequency divider 32 and the second frequency divider 58, and the reference delay count value and the selected frequency are stored in the conversion table 74. Is provided for conversion with the delay count value corresponding to.
[0035]
In this way, if the reference delay count value corresponding to the reference frequency is calculated in advance for each of the vibrating elements, for each of the beam addresses, for each of the focus depths and the like and stored in the memory, the reference delay count value for other frequencies can be obtained. It is only necessary to convert the corresponding delay count value according to the difference in frequency using this reference delay count value, and it is not necessary to hold the delay count values corresponding to all frequencies in the memory. Therefore, the capacity of the memory relating to the transmission delay time can be reduced.
[0036]
Also, when the function of the ultrasonic apparatus is switched, only the corresponding delay count value is converted by the conversion table, so that the setting of the delay count value can be quickly switched.
[0037]
FIG. 2 is an example of the contents of the conversion table 74. The conversion table 74 includes a conversion table 90a for 40 MHz-30 MHz used for conversion between a reference delay count value corresponding to the reference frequency 40 MHz and a delay count value corresponding to the selected frequency 30 MHz, and a reference delay corresponding to the reference frequency 40 MHz. A conversion table 90b for 40 MHz to 24 MHz used for conversion between the count value and the delay count value corresponding to the selected frequency of 24 MHz. Both the conversion table 90a for 40MHz-30MHz and the conversion table 90b for 40MHz-24MHz have two left and right columns, the reference delay count value 92 in the left column, and the delay count value 94a corresponding to the reference delay count value in the right column. , 94b are shown.
[0038]
The left column shows all values from the minimum value to the maximum value that can be represented by the number of bits representing the reference delay count value. For example, if the number of bits representing the reference delay count value is 10 bits, 2 10 reference delay count values are arranged in order from the minimum value to the maximum value. In the figure, decimal notation is used for convenience of explanation, and rounding is used for conversion. For example, in the case of a conversion table 90a for 40 MHz-30 MHz, the reference delay count value is set to 20, and the corresponding delay count value is set to 15 for conversion. The transmission delay time at this time is 20 * 25 nsec = 15 * 33.3 nsec = 500 nsec. The conversion table 90b for 40 MHz to 24 MHz has the same configuration. For example, the reference delay count value is set to 20, and the corresponding delay count value is set to 12 for conversion.
[0039]
The content of the conversion table in FIG. 2 is an example. Instead of using the conversion table as a set of conversion tables for each selected frequency, in one table, for example, a reference delay count value of 40 MHz is arranged in the leftmost column, and 2 A format in which delay count values corresponding to 30 MHz are arranged in the third column and delay count values corresponding to 24 MHz in the third column from the left may be used. In addition to the universal conversion format that can convert all reference delay count values, when the type of reference delay count value actually used is limited, etc., only the type of the limited reference delay count value is used. The conversion format may be limited. Further, in addition to using a table search means for searching for a reference delay count value in a table format such as a conversion table and outputting a corresponding delay count value, a selected frequency and a reference delay count value are inputted to correspond to the selected frequency. A memory that outputs the delay count value, for example, a semiconductor memory such as a ROM may be used.
[0040]
FIG. 3 shows an example in which, in the conversion table, the number of bits representing the reference delay count value is larger than the number of bits representing the delay count value corresponding to the selected frequency. In this way, the conversion becomes more accurate. In the figure, for convenience of explanation, the number of bits representing the delay count value corresponding to the selected frequency of 30 MHz is 4 bits, and the number of bits representing the reference delay count value corresponding to the reference frequency of 40 MHz represents the delay count value in (a). In the case of 4 bits, which is the same as the number of bits, and in (b), the number of lower bits is increased by 1 bit to be 5 bits in total. In FIG. 3, the number of bits is described in binary notation, but it is more convenient to use decimal notation for explanation of the principle, so the count number in decimal notation is also written in parentheses, and the following description is given. However, a value expressed in a decimal system is used. However, the presence / absence of lower bits is indicated by, for example, a difference between (9 + 1 bit) and (9).
[0041]
For example, when the method using 4 bits is compared with the method using 5 bits when the reference delay count value is between 9 and 10, in the former, the reference delay count value is rounded to 10 by, for example, rounding, and this is converted. Therefore, the corresponding delay count value is 8, as shown in FIG. On the other hand, in the latter method using 5 bits, the reference delay count value is converted (9 + 1 bits) as it is without rounding using the conversion table, so that the corresponding delay count value becomes 7 as shown in (b). , A more accurate conversion result can be obtained. Similarly, when the reference delay count value is between 8 and 9, a difference occurs between the method using 4 bits and the method using 5 bits, and the latter results in a more accurate conversion result.
[0042]
In the above description, the number of bits representing the reference delay count value is increased by one bit from the number of bits representing the delay count value corresponding to the selected frequency. However, the number of bits can be further increased. By making the number of bits representing the reference delay count value larger than the number of bits representing the delay count number corresponding to the selected frequency, conversion can be performed more accurately.
[0043]
【The invention's effect】
According to the ultrasonic diagnostic apparatus of the present invention, the capacity of the memory that stores the transmission delay time can be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram of a transmission unit of an ultrasonic diagnostic apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing an example of the contents of a conversion table.
FIG. 3 is a diagram illustrating conversion when the number of bits representing a reference delay count value is increased.
FIG. 4 is a block diagram of a transmission unit of a conventional ultrasonic device.
[Explanation of symbols]
10, 70 Transmitter of ultrasonic diagnostic apparatus, 11 ultrasonic transducer, 12a to 12n vibrating element, 32 frequency divider (selected clock output means), 34a to 34n counter, 36 CPU (calculation means), 40a to 40n delay Count value setting section, 46 clock signal, 48a to 48n counter output signal, 72 reference delay count value holding memory, 74 conversion table (conversion means), 92 reference delay count value, 94a, 94b corresponding delay count value.

Claims (4)

Count a selected clock selected from a plurality of clocks of different frequencies, and when the count value matches the delay count value set for determining the transmission delay time, output the selected clock; A control circuit for generating a transmission pulse of a transmission frequency based on the output,
A transmission circuit that generates a transmission drive pulse to be supplied to the ultrasonic transducer based on the transmission pulse,
An ultrasonic diagnostic apparatus including a transmission unit having
Calculating means for replacing the transmission delay time with the count value of the clock of the reference frequency;
Means for converting a time indicated by a reference count value into a count value of the selected clock, and setting the converted count value as a delay count value for determining the transmission delay time;
An ultrasonic diagnostic apparatus comprising: A plurality of vibrating elements for transmitting and receiving ultrasonic waves,
For each of the vibrating elements, count a selected clock selected from a plurality of clocks of different frequencies, count the value, and set each delay set to determine each transmission delay time corresponding to each of the vibrating elements. A control circuit that, when the count value matches, outputs the selected clock, and generates each transmission pulse of the transmission frequency based on each output;
A transmission circuit that generates each transmission drive pulse to be supplied to each of the vibration elements based on each transmission pulse,
An ultrasonic diagnostic apparatus including a transmission unit having
For each of the vibrating elements, a calculating unit that replaces each transmission delay time with a count value of a clock of a reference frequency,
For each of the vibrating elements, the time indicated by the count value of the clock of the reference frequency is converted into the count value of the selected clock, and the converted count value is set as a delay count value for determining the transmission delay time. Means,
An ultrasonic diagnostic apparatus comprising: In the ultrasonic diagnostic apparatus according to claim 1 or 2,
The means for converting to the delay count value is a conversion table between the count value of the clock of the reference frequency and the delay count value corresponding to each clock of the plurality of different frequencies, and the frequency of the selected clock, An ultrasonic diagnostic apparatus comprising: a memory for receiving a count value of a clock of the reference frequency and outputting a delay count value corresponding to the selected clock. In the ultrasonic diagnostic apparatus according to claim 1 or 2,
An ultrasonic diagnostic apparatus, wherein the number of bits representing the count value of the clock of the reference frequency is larger than the number of bits representing the delay count value corresponding to the selected clock.

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