JP2002345811A - Testing equipment for the front end of an ultrasonic diagnostic device - Google Patents

Abstract

(57) [Problem] To provide a test apparatus of a front end part of an ultrasonic diagnostic apparatus for measuring a delay time with high accuracy. A test apparatus (30) for a front end of an ultrasonic diagnostic apparatus according to the present invention includes: a test signal generator (8) that rises and falls at a predetermined gentle slope; And a measuring unit 18 for measuring the delay time of a plurality of channels from the output signal of the front end unit 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front end device of an ultrasonic diagnostic apparatus.

[0002]

2. Description of the Related Art The principle of an ultrasonic diagnostic apparatus is that a transducer is driven by an electric signal to generate ultrasonic waves, and an ultrasonic signal reflected in a body to be diagnosed is converted into an electric signal by the transducer to perform signal processing. The latest ultrasonic diagnostic equipment divides the transducer into multiple parts, delays and adds the ultrasonic signals received from each transducer, and focuses and deflects the beam. Most do.

In particular, in recent years, due to advances in circuit technology, an ultrasonic diagnostic apparatus that converts an ultrasonic signal received by each transducer into a digital signal and performs delay addition in the state of the digital signal has been increasing.

[0004] When generating ultrasonic waves, each transducer gives a predetermined delay to each transducer so that the ultrasonic waves converge and deflect in a predetermined position and direction.

FIG. 11 is a block diagram of a front end unit 20 of an ultrasonic diagnostic apparatus that performs delay addition using digital signals.

As shown in FIG. 11, a front end unit 20 of the ultrasonic diagnostic apparatus includes anti-aliasing filters 1a to 1d, AD converters 2a to 2d, and FIFO memories 3a to 3d (Fast In Fast). Out
) And an adder 4.

[0007] For example, reflected signals of ultrasonic waves received by four transducers (not shown) are amplified to an appropriate amplitude and input to the anti-aliasing filters 1a to 1d. The anti-alias filters 1a to 1d are used to prevent a signal that has been temporally discretized at the time of AD conversion from causing frequency aliasing, and a low-pass filter is used. The signal that has passed through the anti-aliasing filters 1a to 1d
Discretization and quantization are performed by a to 2d. The digital signals output from the A / D converters 2a to 2d are input to FIFO memories 3a to 3d, delayed by a control by a control circuit (not shown), and added by an adder 4.

When verifying the delay time of each channel in the front end section 20 as described above, FIG.
2 is used.

FIG. 12 is a block diagram showing a conventional front end test apparatus 80. As shown in FIG.

As shown in FIG. 12, anti-aliasing filters 1a to 1d, A / D converters 2a to 2d, FIFO memories 3a to 3d of a prefetch / readout memory, and an adder 4
, A front end unit 20 is configured, and the delay unit 5, the step wave generator 6, and the changeover switch 7 configure a conventional front end test apparatus 80.

Next, the operation of the conventional front end test apparatus 80 for testing the front end will be described.

The delay unit 5 receives a reference trigger signal from a control unit (not shown) of the ultrasonic diagnostic apparatus, outputs a trigger signal to the step wave generator 6 after delaying it by a predetermined delay time. The step wave generator 6 generates a step wave based on the timing of the trigger signal. The changeover switch 7 is sequentially switched. First, a step wave is sent to the anti-aliasing filter 1a, converted into a digital signal by the AD converter 2a, delayed by a time determined by the FIFO memory 3a, and then sent to the adder 4. Sent.

At this time, since no signal is input to the other channels, the output of the adder 4 is output to the FIFO memory 3
The output of a is output as it is. For the output of the adder 4, the timing at which the step wave is output is measured by a measuring device (not shown) such as a logic analyzer, and the delay time is calculated.

Hereinafter, a step wave is similarly input to the front end unit 20 for the other channels, and the delay time is measured.

[0015]

However, the above-described conventional front end test apparatus 80 has several problems.

First, the first problem is that an error occurs in the delay time when discretization is performed in the AD converter. This will be described with reference to the input and output waveform diagrams of the AD converter shown in FIG. As shown in FIG.
The waveform of (a) is the input waveform of the AD converter, and the waveform of FIG. 13 (b) is the output waveform. Here, it is assumed that the AD converter is an ideal one and the AD conversion is performed instantaneously.
The output waveform of the AD converter is discretized at the timing of the interval Ts between the circles. AD
When the step waveform of the input waveform of the converter is input, for example, at timing t1, even if the input waveform rises, this change is not output until the next discretization timing t2. In other words, a time difference of ΔT occurs between the input of the AD converter and the output of the AD converter, and this error is reflected in the delay time measurement.

The second problem is that each of the transducers P0 to P in FIG.
This will be described with reference to a diagram showing the position 7 and the focusing position of the beam.

As shown in FIG. 14A, generally, when a beam having a certain depth on the line of the center o of the transducers P0 to P7 is reflected from the focus position a, the delay time is verified. Done. However, in the conventional front end test apparatus 80 (see FIG. 12), each of the transducers P0
Since the time from P7 to the sound source is kept constant, as shown in FIG. 14B, in a so-called dynamic focus in which the focusing condition is changed for each depth, for example, a beam The delay time of the beam focused at the focus position a is measured, and the vibrator P7 measures the delay time of the beam focused at the beam focus position b, causing a problem that the focus state cannot be correctly grasped.

The present invention has been made to solve such a conventional problem, and eliminates the delay due to the discretization of the AD converter. Further, even if the focusing condition is changed, the same depth is applied to all the oscillators. Eliminate the problem of measurement error due to focal length deviation as a state to receive reflected signals from
An object of the present invention is to provide a test apparatus for a front end portion of an ultrasonic diagnostic apparatus that performs accurate measurement of a delay time.

[0020]

According to the present invention, there is provided a test apparatus for a front end portion of an ultrasonic diagnostic apparatus according to the present invention, comprising: a test signal generating section which rises and falls at a predetermined gentle inclination; A configuration is provided which includes a changeover switch for switching and inputting to a plurality of channels, and a measuring unit for measuring delay times of the plurality of channels from output signals of the front end unit.

With this configuration, it is possible to eliminate the delay due to the discretization of the AD converter by using the test signal that rises and falls with a gentle slope, and measure the delay time with higher accuracy.

The generator may generate a ramp test signal that rises and falls linearly at a predetermined gentle slope.

With this configuration, the delay due to the discretization of the AD converter can be eliminated by using a test signal that rises and falls linearly with a gentle slope, and a more accurate delay time can be measured.

Further, the generator generates a burst-like test signal which rises and falls in a curved manner at a predetermined gentle slope.

With this configuration, the delay due to the discretization of the AD converter can be eliminated by using the test signal that rises and falls in a curved line with a gentle slope, and a more accurate delay time can be measured.

Further, the measuring section measures the delay time after interpolating the discrete output signal from the front end section into a continuous waveform.

With this configuration, it is possible to reduce an error as a measurement using a continuous waveform and measure a delay time with higher accuracy.

Further, the measuring section measures the delay time after DA-converting the discretized output signal from the front-end section, passing it through a low-pass filter and smoothing it.

With this configuration, errors can be reduced by performing measurement using a smoothed waveform, and a more accurate delay time can be measured.

Further, the measuring section measures the delay time using the zero cross point of the output signal waveform from the front end section as a reference point.

With this configuration, it is possible to more accurately measure the delay time from the reference point and measure the delay time with higher accuracy.

Further, the measuring section measures the delay time using an average point calculated from a plurality of zero cross points of the output signal waveform from the front end section as a reference point.

With this configuration, it is possible to more accurately measure the delay time from the reference point and measure the delay time with higher accuracy.

Further, the measuring section measures the delay time using a point at which the amplitude becomes 1/2 before and after the peak of the output signal from the front end section as a reference point.

With this configuration, it is possible to more accurately measure the delay time from the reference point and measure the delay time with higher accuracy.

Further, the measuring section correlates an output signal from the front end section of the channel as a reference with an output signal from the front end section,
It was decided to measure the delay time.

With this configuration, a measurement for obtaining a correlation between output signals is performed to reduce an error due to noise, and a more accurate delay time can be measured.

Further, the generator changes the timing of generating the waveform of the test signal.

With this configuration, it is possible to solve the problem of the measurement error due to the deviation of the focal length, and to measure the delay time with higher accuracy.

[0040]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a test apparatus for the front end unit 30 according to the first embodiment of the present invention.

As shown in FIG. 1, anti-alias filters 1a to 1d for preventing frequency aliasing in discretization
A / D converters 2a to 2d for converting an analog signal to a digital signal, FIFO memories 3a to 3d, and an adder 4 constitute a front end unit 20, and a delay unit 5,
The changeover switch 7, the ramp generator 8, the vertex measurement calculator 9, and the delay time calculator 10 constitute a test device 30 at the front end. The vertex measurement computing unit 9
The measurement unit 18 is configured by the delay time calculator 10.

Next, the operation of the test apparatus 30 of the front end unit according to the first embodiment will be described with reference to FIGS.

A reference trigger signal generated by a control circuit (not shown) of the ultrasonic diagnostic apparatus is input to the delay unit 5, and the delay unit 5 outputs a trigger signal delayed by a predetermined time to the ramp generator 8.

FIG. 2 shows a signal waveform for a test signal generated by the ramp generator 8, and FIG. 2A shows an input waveform when input to the AD converters 2a to 2d.
(B) shows an output waveform when output from the AD converters 2a to 2d.

The ramp generator 8 generates a waveform that gradually rises as shown in FIG. 2A, gradually falls at a certain time as a peak, and returns to the original level. This waveform is input to one of the anti-alias filters 1a to 1d selected by the changeover switch 7. Here, it is assumed that the signal is connected to the contact 7a and input to the anti-aliasing filter 1a. Since the ramp wave signal generated by the ramp generator 8 changes slowly, the anti-alias filter 1
In a, there is no change in the waveform, and the waveform shown in FIG. 2A is directly input to the AD converter 2a, and the waveform shown in FIG. 2B is output. In this waveform, the output of the AD converter 2a is represented by a circle, and the same signal is output from a circle to the next circle. Note that, here, for simplicity of description, it is assumed that there is no conversion delay in an ideal AD converter.

Of the output change of the AD converter 2a, the intersection point P of the linear portion of the rising portion and the falling portion is defined as the delay time of this channel. The calculation of the intersection P from the rise and fall is performed by the vertex measurement calculator 9, and based on the calculation result, the delay time calculator 10 calculates the delay time of the front end of this channel. Similarly, the delay time is calculated for the other channels. By using the ramp wave that rises and falls at a predetermined gentle slope in this way, it is possible to eliminate the delay due to the discretization of the AD converter and accurately measure the delay time.

FIG. 3 shows a block diagram of a test apparatus 40 for a front end unit according to a second embodiment of the present invention.

As shown in FIG. 3, anti-aliasing filters 1a to 1d for preventing frequency aliasing in discretization
A / D converters 2a to 2d for converting an analog signal to a digital signal, FIFO memories 3a to 3d, and an adder 4 constitute a front end unit 20, and a delay unit 5,
Switch 7, burst wave generator 11, interpolator 1
2 and the delay time calculator 10 constitute a test apparatus 40 in the front end section.

Next, the operation of the test apparatus 40 of the front end unit in the present embodiment will be described with reference to FIGS.

A reference trigger signal generated by a control circuit (not shown) of the ultrasonic diagnostic apparatus is input to the delay unit 5, and the delay unit 5 outputs a trigger signal delayed by a predetermined time to the burst wave generator 1.
Output to 1.

FIG. 4 shows a signal waveform for a test signal generated by the burst wave generator 11, FIG. 4A shows an output waveform of the burst wave generator 11, and FIG. FIG. 4 (c) shows an output waveform when input to the device 4;
4 shows an output waveform when input to the interpolator 12.

The burst wave generator 11 generates burst waves for several waves, but generates a shape wave such as a sine wave which changes slowly. A burst wave as shown in FIG. 4A is generated and output to the channel selected by the changeover switch 7. Here, assuming that it is connected to the contact 7a, the anti-aliasing filter 1a, the AD converter 2a, the FIFO
After passing through the memory 3a, the adder 4 outputs a waveform as shown in FIG. This waveform lacks smoothness because it is discretized, and if the delay time is calculated as it is, an error occurs.
Then, the delay time calculator 10 calculates the delay time of the front end portion of this channel after interpolation so as to form a continuous waveform as shown in FIG. Similarly, by sequentially calculating the delay time for the other channels and measuring the delay time of the front end unit, the delay due to the discretization of the AD converter can be eliminated, and the delay time with higher accuracy can be measured. .

FIG. 5 is a block diagram of a test apparatus 50 for a front end unit according to a third embodiment of the present invention.

As shown in FIG. 5, anti-aliasing filters 1a to 1d for preventing frequency aliasing in discretization
A / D converters 2a to 2d for converting an analog signal to a digital signal, FIFO memories 3a to 3d, and an adder 4 constitute a front end unit 20, and a delay unit 5,
The changeover switch 7, the burst wave generator 11, the DA converter 13, and the low-pass filter 14 constitute a front-end test device 50.

Next, the operation of the test apparatus 50 of the front end unit in the present embodiment will be described.

A reference trigger signal generated by a control circuit (not shown) of the ultrasonic diagnostic apparatus is input to a delay unit 5, and the delay unit 5 outputs a trigger signal delayed for a predetermined time to a burst wave generator 1.
Output to 1.

The burst wave generator 11 generates burst waves for several waves, but generates a shape wave such as a sine wave having a gradual change. A burst wave as shown in FIG. 4A is generated and output to the channel selected by the changeover switch 7. Here, assuming that it is connected to the contact 7a, the anti-aliasing filter 1a, the AD converter 2a, the FIFO
After passing through the memory 3a, the adder 4 outputs a waveform as shown in FIG. Since this waveform is discretized and lacks smoothness, and if the delay time is calculated as it is, an error occurs. Therefore, the waveform is converted back to an analog signal by the DA converter 13, smoothed by the low-pass filter 14, and an oscilloscope (not shown) is used. Observe the waveforms, and measure the delay time at the front end of this channel. Similarly, the delay time is measured for other channels in the same manner.
Delay due to discretization of the D converter can be eliminated, and a more accurate delay time can be measured.

A description will be given of a test apparatus for a front end unit according to a fourth embodiment of the present invention.

The same test apparatus as that of the second embodiment shown in FIG. 3 is used as the front end test apparatus in the fourth embodiment.

The operation of the test apparatus for the front end unit according to the fourth embodiment of the present invention will be described with reference to FIGS.

FIG. 6 shows a signal waveform after interpolation output from the interpolator 12.

The signal waveform input to the adder 4 by the same operation as that of the test device 40 in the front end unit in the second embodiment is output by the interpolator 12 as shown in FIG. As shown in FIG. 6, the delay time calculator 10 focuses on one point t1 of the zero cross point in the sine wave of the input burst wave, and sets the time between the base point t0 and the zero cross point t1 based on the zero cross point t1. Is measured as the delay time TD, the delay due to the discretization of the AD converter can be eliminated, and a more accurate delay time can be measured.

A description will be given of a test apparatus for a front end unit according to a fifth embodiment of the present invention.

As the test apparatus for the front end unit in the fifth embodiment, the same apparatus as that of the second embodiment shown in FIG. 3 is used.

The operation of the front end test apparatus according to the fifth embodiment of the present invention will be described with reference to FIGS.

FIG. 7 shows a signal waveform after interpolation output from the interpolator 12.

The signal waveform input to the adder 4 by the same operation as the test apparatus 40 in the front end unit in the second embodiment is output by the interpolator 12 as shown in FIG. As shown in FIG. 7, the delay time calculator 10 pays attention to two zero-crossing points t1 and t2 of the sine wave of the input burst wave, and uses the zero-crossing points t1 and t2 as a reference to set the base point t0 and the zero-crossing point. Time D between t1 and t2
By measuring the average of T1 and DT2 as the delay time DT, the delay due to the discretization of the AD converter can be eliminated, and a more accurate delay time can be measured.

It should be noted that the number of zero-cross points of interest can be three or more.

A description will be given of a test apparatus for a front end unit according to a sixth embodiment of the present invention.

The same test apparatus as that of the second embodiment shown in FIG. 3 is used as the front end test apparatus in the sixth embodiment.

The operation of the test apparatus for the front end unit according to the sixth embodiment of the present invention will be described with reference to FIG.

FIG. 8 shows a signal waveform after interpolation output from the interpolator 12.

The signal waveform input to the adder 4 by the same operation as the test apparatus 40 in the front end unit in the second embodiment is output by the interpolator 12 as shown in FIG. As shown in FIG. 8, the delay time calculator 10 focuses on one of the peaks of the sine wave of the input burst wave, and before and after the peak Pk, the amplitude Ap / of the half of the amplitude Ap of the peak Pk. By obtaining the points t1 and t2 that are 2 and measuring the average of these points t1 and t2 as the delay time DT, the delay due to the discretization of the AD converter can be eliminated, and the accurate delay time can be measured. .

FIG. 9 is a block diagram showing a front end test apparatus 60 according to a seventh embodiment of the present invention.

As shown in FIG. 9, anti-alias filters 1a to 1d for preventing aliasing of frequency in discretization
A / D converters 2a to 2d for converting an analog signal to a digital signal, FIFO memories 3a to 3d, and an adder 4 constitute a front end unit 20, and a delay unit 5,
Switch 7, burst wave generator 11, interpolator 1
2, a memory 15, and a cross-correlator 16 constitute a test device 60 in the front end unit.

Next, the operation of the test apparatus 60 of the front end unit according to the present embodiment will be described with reference to FIGS.

A reference trigger signal generated by a control circuit (not shown) of the ultrasonic diagnostic apparatus is input to the delay unit 5, and the delay unit 5 outputs a trigger signal delayed for a predetermined time to the burst wave generator 1.
Output to 1.

The burst wave generator 11 generates burst waves for several waves, but generates a shape wave such as a sine wave having a gradual change. A burst wave as shown in FIG. 4A is generated and output to the channel selected by the changeover switch 7. Here, assuming that it is connected to the contact 7a, the anti-aliasing filter 1a, the AD converter 2a, the FIFO
The discrete signal output from the adder 4 after passing through the memory 3a is interpolated by the interpolator 12, that is, the sampling interval is shortened in a pseudo manner. First, the signal of the reference channel is fetched into the memory 15, and a signal to be compared with the signal is input to the cross-correlator 16, and a correlation is obtained between the two. Since the waveforms are similar for all channels, the time lag at which the correlation is highest is measured as the delay time. The front-end test apparatus according to the seventh embodiment can reduce errors due to noise, eliminate delays caused by discretization of AD converters, and measure delay times with higher accuracy.

FIG. 10 is a block diagram showing a test apparatus 70 for a front end unit according to an eighth embodiment of the present invention.

As shown in FIG. 10, the anti-aliasing filters 1a to 1a prevent the aliasing of the frequency in the discretization.
d, AD converters 2a to 2d for converting an analog signal into a digital signal, FIFO memories 3a to 3d, and an adder 4. The front end unit 20 includes a variable delay unit 17, a changeover switch 7, The burst wave generator 11 constitutes a test device 70 at the front end.

The front end test apparatus according to the eighth embodiment operates basically in the same manner as that of the first embodiment, except that the delay time of the reference trigger signal is made variable by the variable delay By changing the delay time, the problem of the measurement error due to the shift of the focal length can be solved, the delay due to the discretization of the AD converter can be eliminated, and the delay time with higher accuracy can be measured.

[0083]

The test apparatus for the front end of the ultrasonic diagnostic apparatus according to the present invention has a test signal generating section which rises and falls at a predetermined gentle inclination and switches the test signal to a plurality of channels of the front end section. A configuration including a changeover switch for inputting and a measuring unit for measuring delay times of a plurality of channels from an output signal of a front end unit, and discretization of an AD converter using a test signal rising and falling at a gentle slope. And the delay time with higher accuracy can be measured.

[Brief description of the drawings]

FIG. 1 is a block diagram of a test apparatus for a front end unit according to a first embodiment of the present invention.

FIG. 2 is a signal waveform diagram for a test signal generated by a ramp generator, FIG. 2 (a) is an input waveform diagram when input to an AD converter, and FIG. 2 (b) is an output from the AD converter; Output waveform diagram

FIG. 3 is a block diagram of a test apparatus for a front end unit according to a second embodiment of the present invention.

FIG. 4 is a signal waveform diagram for a test signal generated by a burst wave generator, FIG. 4 (a) is an output waveform diagram of the burst wave generator, and FIG. 4 (b) is an output when input to an adder; FIG. 4C is a waveform diagram, and FIG. 4C is an output waveform diagram when input to the interpolator.

FIG. 5 is a block diagram of a test apparatus for a front end unit according to a third embodiment of the present invention.

FIG. 6 is a signal waveform diagram after interpolation, output from an interpolator according to a fourth embodiment of the present invention.

FIG. 7 is a signal waveform diagram after interpolation output from an interpolator according to a fifth embodiment of the present invention.

FIG. 8 is a signal waveform diagram after interpolation, output from an interpolator according to a sixth embodiment of the present invention.

FIG. 9 is a block diagram of a test apparatus for a front end unit according to a seventh embodiment of the present invention.

FIG. 10 is a block diagram of a test apparatus for a front end unit according to an eighth embodiment of the present invention.

FIG. 11 is a block diagram of a front end unit of the ultrasonic diagnostic apparatus that performs delay addition with a digital signal.

FIG. 12 is a block diagram of a conventional front end test apparatus.

FIG. 13 is a waveform diagram of the input and output of the AD converter, FIG.
FIG. 13A is an input waveform diagram of the AD converter, and FIG.
Output waveform diagram of AD converter

FIG. 14 is a diagram showing a position of each transducer and a focusing position of a beam.

[Explanation of symbols]

 1a-1d Anti-alias filter 2a-2d A / D converter 3a-3d FIFO memory 4 Adder 5 Delayer 6 Step wave generator 7 Changeover switch 8 Ramp wave generator 9 Vertex measurement calculator 10 Delay time calculator 11 Burst wave generator DESCRIPTION OF SYMBOLS 12 Interpolator 13 DA converter 14 Low-pass filter 15 Memory 16 Cross-correlator 17 Variable delay 18 Measurement unit 20 Front-end unit 30 to 70 Front-end unit test apparatus

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4C301 AA01 BB23 EE11 GB02 HH27 HH33 HH37 HH38 JB03 JB29 JB38 LL05 LL17

Claims (10)

[Claims] A test signal generator that rises and falls at a predetermined gentle slope; a changeover switch for changing over the test signal to a plurality of channels of a front end unit; A testing apparatus for a front end unit of an ultrasonic diagnostic apparatus, comprising: a measuring unit for measuring delay times of a plurality of channels. 2. The front end unit according to claim 1, wherein the generator generates a test signal of a ramp wave that rises and falls linearly at a predetermined gentle slope. Testing equipment. 3. The front end of an ultrasonic diagnostic apparatus according to claim 1, wherein the generator generates a test signal of a burst-like wave that rises and falls in a curved manner at a predetermined gentle slope. Part testing equipment. 4. The ultrasonic diagnostic apparatus according to claim 1, wherein the measuring section measures the delay time after interpolating the discrete output signal from the front end section to form a continuous waveform. Testing equipment for the front end. 5. The measurement unit according to claim 1, wherein the measurement unit measures a delay time after performing a D / A conversion on the discretized output signal from the front end unit, passing the signal through a low-pass filter, smoothing the signal, and then smoothing the signal. Test equipment for the front end of the ultrasonic diagnostic equipment. 6. The ultrasonic diagnostic apparatus according to claim 1, wherein the measurement unit measures the delay time using a zero cross point of an output signal waveform from the front end unit as a reference point. Testing equipment for the front end. 7. The measurement unit according to claim 1, wherein the measurement unit measures the delay time using an average point calculated from a plurality of zero-cross points of the output signal waveform from the front end unit as a reference point. A testing device for a front-end part of the ultrasonic diagnostic apparatus according to 1. 8. The apparatus according to claim 1, wherein the measuring section measures the delay time using a point at which the amplitude becomes 1/2 before and after the peak of the output signal from the front end section as a reference point. 4. A test device for a front end portion of the ultrasonic diagnostic device according to 1 or 3. 9. The measurement unit correlates an output signal from the front end unit of the channel serving as a reference with an output signal from the front end unit, and measures a delay time. Claim 1 or 3 characterized by the above-mentioned.
A testing device for a front-end part of the ultrasonic diagnostic apparatus according to 1. 10. The apparatus according to claim 1, wherein the generator changes a timing of generating a waveform of the test signal.