JP2001137777A - Ultrasonic transmission signal generation circuit and ultrasonic diagnosis apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic oscillation transmission signal generation apparatus for easily generate and supply pulsed operation signals suitable for frequency properties of a wide band ultrasonic vibrator. SOLUTION: The ultrasonic oscillation signal generation apparatus comprises a reference signal generation means 11, a first pulse width variable apparatus 12 for generating first pulsed operation signals with a prescribed pulse signal width based on the reference signals from the reference signal generation means 11, a second pulse width variable apparatus 14 for generating second pulsed operation signals with a pulse signal width different from that of the first pulsed operation signals through a delay line 13 for delaying the reference signals, and an ultrasonic oscillator operation signal generation means 17 for generating ultrasonic oscillator operation signals with the period of a reciprocal number of approximately the center frequency of an ultrasonic oscillator 18 based on the first and the second pulsed operation signals from the first and the second pulse width variable apparatuses 12, 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus and an ultrasonic endoscope apparatus mainly used for medical purposes.
In particular, the present invention relates to a device for generating a pulse signal for driving an ultrasonic transducer.

[0002]

2. Description of the Related Art An ultrasonic diagnostic apparatus for radiating an ultrasonic wave into the body by making an ultrasonic vibrator come into contact with the skin surface of a body, or inserting an ultrasonic vibrator into a body cavity and applying the ultrasonic wave to the ultrasonic wave An ultrasonic endoscope device that radiates ultrasonic waves from a transducer to a predetermined object in a body cavity to diagnose the inside of the body cavity (hereinafter, these ultrasonic diagnostic devices and ultrasonic endoscope devices are collectively referred to simply as an ultrasonic endoscope device). An ultrasonic diagnostic apparatus) images a state of transmission of ultrasonic waves and reflection from an object as a tomographic image to perform medical diagnosis of soft tissue of a body.

A conventional ultrasonic diagnostic apparatus generates a predetermined ultrasonic wave on an ultrasonic vibrator based on a driving pulse signal supplied from an ultrasonic oscillation pulse signal generating apparatus, and radiates the ultrasonic wave to an object.

An example of an ultrasonic oscillation pulse generator for generating a drive pulse signal supplied to the ultrasonic transducer will be described with reference to FIG.

Reference numeral 51 in FIG. 5 denotes a switch using a field effect transistor (FET) (hereinafter referred to as an FET switch). A reference pulse is input to the gate of the FET switch 51, and the source is a reference potential. And the drain is connected to a potential + HV via a resistor 52. A pulse transformer 53 is provided at both ends of the resistor 52.
Are connected. This pulse transformer 5
An ultrasonic transducer 54 and a matching coil 55 are connected in parallel to both ends of the secondary winding 3 via a relatively long signal cable arranged in an ultrasonic diagnostic apparatus (not shown).

The ultrasonic oscillating pulse signal generator having such a configuration is turned on by a reference positive pulse input to the FET switch 51, and during the ON period of the FET switch 51, the potential of the resistor 52 and the pulse transformer 53 are changed from the potential + HV. A potential is supplied through the parallel circuit of the primary winding and the drain and source of the FET switch 51. The drive signal of the potential + HV of the ultrasonic transducer 54 is generated in the secondary winding by the electric potential supplied to the primary winding of the pulse transformer 53. Generally, the impedance of the ultrasonic transducer 54 is matched by a matching coil 55 connected in parallel with the ultrasonic transducer 54 in order to efficiently oscillate a specific center frequency fo.

The lower the center frequency fo of the ultrasonic waves oscillated and emitted from the ultrasonic transducer 54, the deeper the tomographic image can be obtained, but the lower the resolution. Conversely, the higher the center frequency fo, the better the resolution, but no deep tomographic image can be obtained. Therefore, a plurality of ultrasonic endoscopes having different center frequencies fo according to the diagnosis have been required.

On the other hand, recently, a broadband ultrasonic transducer having a wide frequency band from low to high has been developed, and an ultra-high-frequency ultrasonic transducer which has a high resolution and can obtain a tomographic image in a deep part has been obtained. Development and commercialization of an ultrasonic diagnostic apparatus are also underway.

When a broadband ultrasonic vibrator is driven, if a matching coil for impedance matching with the wideband ultrasonic vibrator is connected in parallel, the frequency band is narrowed, and the frequency band is reduced without using a matching coil. Alternatively, when driven by a negative reference half-wave pulse, a cable for transmitting the pulse becomes equivalent to a low-pass filter, and the high-frequency component of the pulse is attenuated.

When such a broadband ultrasonic vibrator is used, it is disclosed in Japanese Patent Application Laid-Open No. 4-274755 that a sine wave having one cycle of positive and negative is used as a drive signal of the ultrasonic vibrator. . An ultrasonic oscillation pulse signal generating apparatus using the driving signal of one cycle of positive and negative will be described with reference to FIG.

This ultrasonic oscillation pulse signal generating device has an E
A reference positive pulse signal is supplied to the gates of the FT switches 61 and 64, and each source is connected to a reference potential. The drain of the FET switch 61 is connected in parallel with a resistor 62 and a primary winding 63a of a pulse transformer 63, and the drain of the FET switch 64 is connected in parallel with a resistor 65 and a primary winding 63b of a pulse transformer 63. And is connected to the potential + HV. The secondary winding 63c of the pulse transformer 63 is connected to an ultrasonic transducer 66 disposed in an ultrasonic diagnostic apparatus via a relatively long signal cable.

The primary winding 6 of the pulse transformer 63
Reference numerals 3a and 63b denote windings having opposite directions, and the potential supplied from the potential + HV is reversed when the FET switches 61 and 64 are turned on / off.

The primary winding 63 of the pulse transformer 63
a and 63b are supplied with the potential + HV by turning on / off the FET switches 61 and 64, and the secondary winding 63
In c, a drive output pulse of one cycle of positive and negative cycles for driving the broadband ultrasonic transducer 66 having positive and negative potentials (± HV) based on the reference potential 0 is generated. When the broadband ultrasonic transducer 66 is driven by the positive / negative drive output pulses, the power of the low frequency components is slightly reduced, but the power of the high frequency components attenuated by the cable can be increased.

However, in order to oscillate a wide band ultrasonic wave within the frequency band of the wide band ultrasonic oscillator 66, it is necessary to widen the reference pulse supplied to the FET switches 61 and 64. Then, there is a deviation from the frequency of the ultrasonic transducer 66, and there is a problem that efficient ultrasonic oscillation cannot be performed.

[0015]

With the widespread use of ultrasonic diagnostic equipment, it is necessary to expand the diagnostic range by using a broadband ultrasonic transducer and to obtain a device having a higher resolution and a deeper depth at which ultrasonic waves can reach. It is supposed to be. For that purpose, it is required to broaden the pulse signal for efficiently driving the broadband ultrasonic transducer. However, as shown in FIG. 6, when the broadband ultrasonic transducer is driven by the drive pulse signals of the positive and negative potentials, if the center frequency of the drive pulse signal is shifted, the frequency characteristics of the broadband ultrasonic transducer may differ. A gap occurs, and the performance of the broadband ultrasonic vibrator cannot be fully utilized, resulting in a problem that the resolution and the depth of the ultrasonic wave are reduced.

In order to make the frequency characteristics of the broadband ultrasonic transducer coincide with the center frequency of the driving pulse signal, it is possible to solve the problem by providing an arbitrary waveform generating circuit or the like for performing complicated calculations. In addition, there has been a problem that the circuit configuration becomes complicated and large-scale, and the cost rises.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to generate an ultrasonic transmission pulse signal capable of generating a broadened drive pulse signal without changing the center frequency of the drive pulse signal supplied to the broadband ultrasonic transducer. It is intended to provide a device.

[0018]

According to a first aspect of the present invention, there is provided an ultrasonic transmission signal generating circuit for generating a reference signal which is used as a reference for a transmission signal applied to an ultrasonic vibrator; Generated based on a reference signal from the
And a transmission signal having a second width different from the first width, starting from a substantially end of the transmission signal having the first width, the center frequency of the ultrasonic transducer. And an ultrasonic vibrator drive signal generating means for generating an ultrasonic vibrator drive signal having a period substantially equal to the reciprocal of the above.

According to a second aspect of the present invention, an ultrasonic diagnostic apparatus includes the ultrasonic transmission signal generating circuit according to the first aspect.

The center frequency of the driving pulse signal generated by using the positive and negative pulses having different pulse widths by the ultrasonic transmission signal generating circuit according to the first invention is the reciprocal of the center frequency of the ultrasonic vibrator, so that the resolution and the resolution can be improved. A broadband ultrasonic wave having a good depth of penetration can be obtained. By using this ultrasonic transmission signal generation circuit in an ultrasonic diagnostic apparatus, a diagnostic image can be obtained as to whether the resolution of the soft part of the body cavity is good.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an ultrasonic transmission pulse generator (ultrasonic oscillation signal generator) according to the present invention.
FIG. 2A is a block diagram showing a configuration of one embodiment, and FIG. 2A shows an ultrasonic transmission pulse generator (ultrasonic oscillation signal generator).
FIG. 2B is a block diagram showing a configuration of a pulse width variable device used in the first embodiment. FIG. FIG. 3 is an explanatory diagram illustrating a drive pulse signal obtained by the ultrasonic transmission pulse device (ultrasonic oscillation signal generation device) according to the present invention.

Reference numeral 11 in FIG. 1 denotes a pulse trigger generator for generating a reference pulse signal.
The reference pulse generated by the first pulse width variable device 12
And a second pulse width variable unit 14 via the delay line 13. The delay line 13 supplies a delayed reference pulse signal to the second pulse width variable unit 14 by delaying the reference pulse signal from the pulse trigger generator 11 by the pulse signal width. The first and second pulse width changers 12, 14 have different pulse width adjustment values,
The width of the reference pulse is adjusted and supplied to the gates of the first FET switch 15 and the second FET switch 16. The sources of the first and second FET switches 15 and 16 are connected to the reference potential, and the drain is supplied with the potential + HV via the primary windings 17a and 17b of the pulse transformer 17. The primary windings 17a and 17b of the pulse transformer 17 are arranged such that the directions of the current supplied from the potential + HV are different. The FET switches 15 and 16 are connected to the first and second pulse width variable devices 12 and
The pulse transformer 17 is turned on / off by the pulse width-adjusted reference pulse signal supplied from the
The potential + HV is supplied to the next windings 17a and 17b. The potential + HV supplied to the primary winding 17a or 17b
The output pulse signal generated in the secondary winding 17c based on the above is supplied to the ultrasonic vibrator 18 and oscillates and emits a predetermined ultrasonic wave.

The pulse width of the reference pulse signal adjusted by the first pulse width variable unit 12 is narrow, and the pulse width of the reference pulse signal adjusted by the second pulse width variable unit 14 is the first pulse width. The pulse width is adjusted so as to be wider than the pulse width of the reference pulse signal adjusted by the pulse width variable unit 12.
Thus, during the period of the pulse width of the reference pulse signal whose pulse width has been adjusted by the first pulse width
Of the pulse transformer 1 is turned on.
7, an output pulse of a positive potential + HV from the reference potential is generated in the secondary winding 17c by the potential + HV supplied to the primary winding 17a. When the first FET switch 15 is turned off, the second FET switch 16 is turned on during the pulse width of the reference pulse signal whose pulse width has been adjusted by the second pulse width variable unit 14, and With the potential + HV supplied to the primary winding 17b of the transformer 17, an output pulse of a potential −HV in the negative direction from the reference potential is generated in the secondary winding 17c. The output pulse of one cycle in the positive direction and the negative direction generated in the secondary winding 17c of the pulse transformer 17 is the reciprocal 1 of the center frequency f0 of the ultrasonic transducer 18.
/ F0, and the output pulse drives the ultrasonic vibrator 18 to oscillate ultrasonic waves.

The pulse transformer 17 and the ultrasonic vibrator 18 are connected by a signal cable. Particularly, in the case of an ultrasonic endoscope, the ultrasonic vibrator 18 is inserted into a body cavity. Since it is arranged at the distal end of the endoscope insertion section that is not yet used, a relatively long signal cable arranged inside the endoscope insertion section is used.

Next, a detailed configuration of the first and second pulse width variable devices 12 and 14 will be described with reference to FIG. The configurations of the first and second pulse width changers 12 and 14 are the same except for some conditions.

The reference pulse signal supplied from the pulse trigger generator 11 is supplied to a movable piece 22a of a switch 22 controlled by a CPU 21. A first pulse width adjusting circuit 23 is provided on one fixed piece 22 b of the switch 22.
a, and the other fixed piece 22c is connected to the second pulse width adjusting circuit 23b. These first and second
The pulse width adjusting circuits 23a and 23b of the
2 and delay circuits 24a, 24b connected to the respective fixed pieces 22b, 22c, and AND circuits 26a, 26
b, and NAND circuits 25a and 25b connected between the outputs of the delay lines 24a and 24b and the other input terminals of the AND circuits 26a and 26b. Outputs of the AND circuits 26a and 26b of the first and second pulse width adjusting circuits 23a and 23b are connected to input terminals of an OR circuit 27, respectively, and an output of the OR circuit 27 is connected to the FE.
It is connected to T switches 15 and 16.

The delay lines 24a and 24b
Are set to different values, and the delay lines 24a and 2
A delay amount different from that of 4b is set. That is, the delay amount D1 of the delay line 24a of the first pulse width variable unit 12 is smaller than the delay amount D2 of the delay line 24b of the first pulse width variable unit 12 (D1 <D2), and the second pulse width variable Delay D of the delay line 24a of the detector 14
3 is a delay line 24 of the second pulse width variable device 14.
b is smaller than the delay amount D4 (D3 <D4) and the first
Are set so that the delay amounts of the pulse width variable device 12 and the second pulse width variable device 14 have different values (D1 <D2 ≠ D3 <D4).

The first and second pulse width variable devices 1
2 and 14, the reference pulse signal supplied to the movable piece 22a of the switch 22 directly from the pulse trigger generator 11 or via the delay line 13 is transmitted to the CPU 21.
The movable piece 22a of the switch 22 is
2b, the reference pulse signal A shown in FIG. 2 (b) is supplied to the delay line 24a and one input terminal of the AND circuit 26a via the fixed piece 22b. Supplied. The reference pulse signal A generates a delay pulse signal B delayed by a delay amount set by the delay line 24a and supplies the delayed pulse signal B to the NAND circuit 25a. The NAND circuit 25a inverts the polarity of the supplied delay pulse signal and supplies the inverted delay pulse signal C to the other input terminal of the AND circuit 26a. The AND circuit 26 a generates an adjusted pulse signal D whose pulse width has been adjusted from the reference pulse signal A and the inverted delayed pulse signal C, and supplies the adjusted pulse signal D to the OR circuit 27. OFF circuit 2
7 is the first and second FET switches 15 or 1 based on the adjustment pulse signal D supplied from the AND circuit 26a.
6 is turned on to supply the potential + HV to the primary winding 17a or 17b of the pulse transformer 17 to generate a positive or negative ultrasonic transducer drive signal from the reference potential to the secondary winding 17c. .

That is, during the period when the first FET switch 15 is on with the adjustment pulse D generated by the pulse width adjustment circuit 23a of the first pulse width variable unit 12 and output from the OR circuit 27, the pulse transformer 17 Primary winding 1
A drive output pulse signal in the positive direction is generated from the reference potential excited by the potential + HV supplied to 7 a and supplied to the ultrasonic transducer 18. On the other hand, based on the reference pulse signal delayed by the delay line 13, the second pulse generated by the pulse width adjustment circuit 23a of the second pulse width variable While the FET switch 16 is on, the pulse transformer 17
A drive output pulse signal in the negative direction is generated from the reference potential excited by the potential + HV supplied to the next winding 17 b and supplied to the ultrasonic transducer 18.

At this time, the first pulse width variable device 12
The delay line 24a of the pulse width adjustment circuit 23a and the pulse width adjustment circuit 23a of the second pulse width
, The drive output pulse signal supplied to the ultrasonic transducer 18 has a value different from the drive output pulse width in the positive direction and the drive output pulse width in the negative direction from the reference potential. Will have. Thereby, the frequency band of the drive output pulse signal composed of the positive and negative pulse signals supplied to the ultrasonic transducer 18 is widened.

The driving output pulse signal generated in the secondary winding of the pulse transformer 17 has one cycle from the rising from the reference potential in the positive direction to the falling from the negative direction to the reference potential. Center frequency f0 of child 18
Is set to be the reciprocal of (1 / f0).

Next, the first and second pulse width variable devices 1
When the switches 22 and 14 select the fixed piece 22c under the control of the CPU 21, in the pulse width adjustment circuit 23b, the adjustment pulses D whose pulse width has been adjusted based on the reference pulse signal A are respectively transmitted to the first pulse. The driving output pulse signal is supplied from the pulse transformer 17 to the ultrasonic vibrator 18 by the switching operation of the first and second FET switches 15 and 16.

That is, by selecting the pulse width adjusters 23a and 23b of the first and second pulse width changers 12 and 14 with the switch 22, drive output pulse signals in different frequency bands are obtained, The vibrator 18 can oscillate ultrasonic waves in different frequency bands. The selection of the switch 22 is switched by the instruction of the operator of the ultrasonic diagnostic apparatus via the CPU 21.

The relationship between the frequency bands of drive output pulses supplied to the ultrasonic transducer 18 generated by the ultrasonic transmission pulse generator (ultrasonic oscillation signal generator) according to the present invention will be described with reference to FIG. FIG. 3A shows a drive output pulse having the same value of the positive and negative pulse widths of the conventional ultrasonic transmission pulse generator, and FIG. 3B shows an ultrasonic transmission pulse generator (ultrasonic oscillation signal) according to the present invention. The driving output pulses having different positive and negative pulse widths of the generators are shown, and the horizontal axis represents time T, and the vertical axis represents positive and negative voltages based on the reference potential 0. FIG. 3C is a frequency characteristic showing the frequency f on the horizontal axis and the output power of the ultrasonic transducer 18 on the vertical axis, and the waveform (a) in the figure shows the conventional frequency characteristic shown in FIG. The waveform (b) in the figure shows the frequency characteristic according to the present invention.

As can be seen from FIG. 3, in the case of the conventional drive output pulse having the same positive / negative drive pulse period T / 2, a large output power can be obtained with reference to the center frequency f0, but the frequency band is narrow (f1). Become. On the other hand, by making the drive pulse width in the positive direction different from the drive pulse width in the negative direction according to the present invention, the output power at the center frequency is slightly reduced, but the frequency band can be set wider (f2).

As described above, according to the present invention, it is possible to control the oscillation of the ultrasonic vibration with the depth and the resolution corresponding to the depth of the object of the ultrasonic diagnosis. The pulse width variable circuits 12 and 1
4 has been described using an example in which two pulse width adjustment circuits 23a and 23b are provided. However, by providing three or more pulse width adjustment circuits and making the delay amounts of the respective delay lines 24 different, Ultrasonic oscillation of one or more different frequency bands is also possible.

Next, another embodiment of the present invention will be described with reference to FIG. In the configuration of the ultrasonic transmission pulse generator according to the other embodiment, a reference pulse signal from the pulse trigger generator 11 is input to an input terminal 30, as shown in FIG. The first pulse width variable device 12 ′ connected to the input terminal 30 includes a first flip-flop circuit 31 and a first digital delay line 32, and is connected to an input terminal of the first flip-flop circuit 31. Is supplied with a reference pulse signal from the input terminal 30, a driving potential of +5 V is connected to the terminal D, and the output terminal Q
Is connected to the first digital delay line 32,
The output of the first digital delay line 32 is connected to the FET switch 15 and the clear terminal CLR of the first flip-flop circuit 31.

The input terminal 30 is connected to a second pulse width variable unit 14 ′ via a second digital delay line 33.
It is connected to the. The second digital delay line 33 is obtained by digitizing the delay line 13. The output of the second digital delay line 33 is connected to a second pulse width variable unit 14 '. The second pulse width variable device 14 'is composed of a second flip-flop circuit 34 and a third digital delay line 35, and the input terminal of the second flip-flop circuit 34 is connected to the second digital delay circuit 34'. A delay reference pulse signal is supplied from a line 33, a terminal D is connected to a drive potential of +5 V, an output terminal Q is connected to a third digital delay line 35, and the output of the digital delay line 35 is connected to the FET switch 16 And the clear terminal CLR of the second flip-flop circuit 34.

The first to third digital delay lines 32, 33 and 35 are delay lines whose delay can be controlled by 8-bit digital data from a CPU (not shown). Line 32
The delay amount of the second digital delay line 33 is set to a value delayed by the pulse width of the reference pulse signal.

Next, the first and second pulse width variable devices 1
The operations 2 ′ and 14 ′ will be described with reference to FIG. Waveform A in FIG. 4B is a reference pulse signal supplied to the input terminals of the first and second flip-flop circuits 31, 34. However, the reference pulse signal supplied to the input terminal of the second flip-flop circuit 34 is different from the reference pulse signal supplied to the input of the first flip-flop circuit 12 'by the second digital delay line. The input is delayed by the delay amount delayed at 33. The first and second flip-flop circuits 31 and 34 output a pulse signal having a waveform Q from an output terminal Q based on a reference pulse signal input to an input terminal. The signal is delayed by the three digital delay lines 32 and 35 to generate a pulse signal of waveform C. When this waveform C is input to the clear terminals CLR of the first and second flip-flop circuits 31, 34, the output terminal Q goes low, and the first and third digital delay lines 32, 3
The pulse width adjusted pulse signal of the waveform C having the width delayed by the delay amount of 5 is supplied to the first and second FET switches 15 and 15,
16. At this time, the on-periods of the first FET switch 15 and the second FET switch 16 are different due to the difference in the amount of delay between the first and third digital delay lines 32 and 35.

That is, the first digital delay line 3
By setting the delay amount of 2 to a value smaller than the delay amount of the third digital delay line 35, the ON period of the first FET switch 15 becomes shorter than the ON period of the second FET switch 16. As a result, the drive pulse signal excited in the secondary winding 17c of the pulse transformer 17 has a pulse width in the negative direction from the reference potential longer than that in the positive direction from the reference potential. As in the embodiment of the present invention, the ultrasonic transducer 18 having a wide frequency band is used.
To generate and supply a drive output pulse signal.

The delay amounts of the first to third digital delay lines 32, 33, and 35 are not shown in FIG.
By changing based on the digital data from the PU, it becomes possible to generate and supply a drive pulse signal having a different frequency band around the center frequency f0 of the ultrasonic vibration. By changing the frequency band of the drive output pulse of the acoustic transducer, it is possible to selectively generate a wide range of ultrasonic vibration having a depth and a resolution corresponding to an object.

[Appendix] As described in detail above, according to the embodiment of the present invention, the following configuration can be obtained.

(1) Reference signal generating means for generating a reference signal serving as a reference for a transmission signal applied to the ultrasonic transducer;
Generated based on a reference signal from the reference signal generation means,
A transmission signal having a first width, and a transmission signal having a second width different from the first width, starting from a substantially end of the transmission signal having the first width; An ultrasonic transmission signal generating circuit, comprising: an ultrasonic oscillator drive signal generating means for generating an ultrasonic oscillator drive signal having a cycle of a value substantially opposite to the center frequency.

(2) An ultrasonic diagnostic apparatus comprising the ultrasonic transmission signal generating circuit according to (1).

(3) The ultrasonic vibrator drive signal generating means is a first pulse width varying means for generating the first transmission signal having a predetermined signal width based on a reference signal from the preceding reference signal generating means. And a second pulse width varying means for delaying the reference signal and generating the second transmission signal having a signal width different from the first transmission signal based on the delayed reference signal, An ultrasonic transmission signal generating means for generating an ultrasonic transmission signal having one positive and negative cycle based on the first and second transmission signals generated by the first and second pulse width variable means. The ultrasonic transmission signal generation circuit according to (1).

(4) Positive / negative transmission generated by the ultrasonic transmission signal generation means based on first and second transmission signals having different signal widths from the first and second pulse width variable means. The cycle of the signal falling from the reference potential to the reference potential in the positive direction to the reference potential in the negative direction is set to be the reciprocal of the center frequency of the ultrasonic transducer, wherein Sound wave transmission signal generation circuit.

(5) Each of the first and second pulse width varying means is provided with a plurality of pulse width varying functions for generating transmission signals having different signal widths, and by selecting a combination of the plurality of pulse width varying functions. The ultrasonic transmission signal generating circuit according to (3) or (4), wherein the ultrasonic transmission signal generating means generates transmission signals in different frequency bands to drive the ultrasonic transducer.

(6) The ultrasonic transmission signal generating circuit according to any one of (1), (3) to (5), wherein the first and second pulse width variable means have digitally controllable programmable delay means.

[0050]

As described above, according to the present invention, when a drive pulse signal having one positive and negative cycle for driving a broadband ultrasonic transducer is generated, the drive pulse signal is generated based on a reference signal from a reference signal generating means.
The signal width of the positive direction reference signal and the signal width of the negative direction reference signal are made different, and the period of the ultrasonic vibrator drive signal generated based on the positive and negative direction reference signals is set to the period of the ultrasonic vibrator. By setting the reciprocal of the center frequency, a broadband ultrasonic transducer drive signal can be generated, and by changing the signal width of the positive / negative reference signal, the ultrasonic vibration having the depth of penetration and the resolution corresponding to the diagnosis target is obtained. Is generated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of an ultrasonic transmission pulse generator according to the present invention.

FIGS. 2A and 2B are explanatory diagrams of a pulse width variable device used in the ultrasonic transmission pulse device according to the present invention. FIG. 2A is a block diagram showing a configuration of the pulse width variable device, and FIG. Explanatory drawing explaining operation | movement of a variable device.

3A and 3B are explanatory diagrams for explaining a driving pulse signal obtained by the ultrasonic transmission pulse device according to the present invention, FIG. 3A is an explanatory diagram of a conventional driving pulse signal, and FIG. FIG. 3C is an explanatory diagram showing a difference between the present invention and a conventional frequency band.

FIG. 4 is a block diagram showing a configuration of another embodiment of the ultrasonic transmission pulse generator according to the present invention.

FIG. 5 is a block diagram showing a configuration of a conventional ultrasonic transmission pulse generator.

FIG. 6 is a block diagram showing a configuration of a conventional ultrasonic transmission pulse generator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Pulse trigger generator 12 ... First pulse width variable device 13 ... Delay line 14 ... Second pulse width variable device 15 ... First FET switch 16 ... Second FET switch 17 ... Pulse transformer 18 ... Ultrasonic wave Vibrator 21 CPU 22 Switch 23a First pulse width adjustment circuit 23b Second pulse width adjustment circuit 24a First delay line 24b Second delay line 25a, 25b NAND circuits 26a, 26b AND circuit 27 ... OR circuit

Claims (2)

[Claims] 1. A reference signal generating means for generating a reference signal serving as a reference for a transmission signal to be applied to an ultrasonic vibrator; and a reference signal generated from the reference signal from the reference signal generating means.
A transmission signal having a first width, and a transmission signal having a second width different from the first width, starting from a substantially end of the transmission signal having the first width; An ultrasonic transmission signal generating circuit, comprising: an ultrasonic vibrator drive signal generating means for generating an ultrasonic vibrator drive signal having a cycle of a value substantially opposite to the center frequency. 2. An ultrasonic diagnostic apparatus comprising the ultrasonic transmission signal generating circuit according to claim 1.