JPH05223793A - Ultrasonic receiving dynamic focus circuit - Google Patents

Abstract

PURPOSE:To reduce the scale of the focus circuit and eliminate switching noise from the circuit by connecting the collectors of a plurality of transistors to each tap of a delay line and making signals to the delay line constant-current outputs by commonly using the emitters of the transistors. CONSTITUTION:Received ultrasonic signals are inputted to the base B of a transistor 30 and corresponding constant-current outputs are supplied to the emitter E of a transistor 2. The timing required for taps 10 and a signal which becomes an 'H' level during a required period are generated by means of a logic control circuit and inputted to the base B of the transistor 2. When the input signal is inputted to an integration circuit, by-input a logic signal to a base signal generation circuit 4, a base signal which is proportional to the period H of the input signal at a similar inclination irrespective of the duration of the period H can be inputted to the transistor 2 when the integration signal is clamped by means of a diode and diode bias voltage. Therefore, the occurrence of switching noise can be eliminated by means of a simple circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic wave receiving dynamic focus circuit. A convergent wavefront can be formed by delaying an ultrasonic pulse for driving each probe (vibrator) with a transducer in which a large number of probes are arranged in an array.

This has the effect of narrowing the beam diameter as in the case of using an acoustic lens or a concave vibrator. This is called electronic focus. It is necessary to focus this ultrasonic wave similarly at the time of reception.

FIG. 6 is a diagram showing the principle of electronic focusing upon reception, and FIGS. 7 and 8 are diagrams showing the principle of dynamic focusing. As shown in FIG. 6, in each probe (transducer), the received ultrasonic echo signal is focused by using electronic focus for delaying a predetermined time,
If the phases are aligned and added at the addition points, the width of the ultrasonic beam near the focus point can be narrowed and the resolution can be improved, as shown in the figure.

However, the width of the ultrasonic beam expands in a place other than the vicinity of the focal point. As shown in FIG. 7A, when the focus point is set at a short distance of the probe, the width of the ultrasonic beam is widened at a long distance and the ultrasonic tomographic image is deteriorated.

On the contrary, as shown in FIG. 7B, when the focus point is set at a long distance, the ultrasonic beam cannot be sufficiently narrowed at a short distance, so that the ultrasonic tomographic image deteriorates. Therefore, as shown in FIG. 8 (c), it is conceivable to move the focus point from a short distance to a long distance to always maintain the best ultrasonic beam width.

Although it is possible to focus only on a certain point in one transmission, the focus point can be dynamically moved during reception, which is called reception dynamic focus. By changing the focus point at the time of reception, the width of the ultrasonic beam can be made narrower than the fixed focus regardless of the depth.

Conventionally, various techniques have been known as the ultrasonic receiving dynamic focus technique, but there are problems such as an increase in circuit scale, a distortion of received waveform, and a problem of switching noise. Yes,
What is needed is an ultrasonic receiving dynamic focus circuit that can effectively perform dynamic focus.

[0008]

2. Description of the Related Art FIG. 9 is a diagram for explaining a conventional ultrasonic receiving dynamic focus circuit, in which (a) shows a case where a delay group is switched by an analog switch, and (b) shows a delay using a variable capacitance diode. The line shows the case where the delay amount is changed by changing the voltage applied to the varactor diode, and (c) shows the case where the delay amount is changed by controlling the phase of the received signal with the phase of the local oscillator.

First, in the circuit shown in FIG. 9A, the delay line 1 with taps is used to change the delay amount by switching each delay tap from A to B at the time of reception. Thereby, the focus by A and the focus by B are obtained.

In the circuit shown in FIG. 9 (b), the voltage applied to the variable capacitance diode (D) 11 is changed so that the delay line
It changes the delay amount of 1. Further, FIG. 9 (c) is published in Japanese Patent Application Laid-Open No. 54-96286, and in summary, it corresponds to each probe before phasing addition of the delay amount from the delay line 1. Then, a variable phase shifter as shown in the figure is provided to enable addition with accurate phase coherence to realize the above-mentioned dynamic focus. In the variable phase shifter, the received signal is frequency-modulated by the heterodyne processing by the mixer, and the phase of the received signal is controlled by the phase of the local oscillator used at that time. That is, the ultrasonic signal received from the probe is frequency-modulated by the mixer, input to the delay line 1 and after the required delay, the delayed ultrasonic received signal from each probe 1 is added. Will be done.

[0011]

The circuit for switching the taps of the delay line 1 shown in FIG. 9 (a) has a problem that switching noise is added to the received signal when the taps are switched.

Further, the variable capacitance diode shown in FIG. 9 (b)
In the circuit using (D), there is a problem that the impedance of the delay line 1 changes, reflection occurs on the delay line 1, and the received waveform is distorted.

Further, the variable phase shifter shown in FIG. 9 (c) is provided,
In a circuit that performs addition with accurate phase coherence, there are problems that a large delay cannot be applied due to phase changes and that the circuit scale becomes large.

In view of the above-mentioned conventional drawbacks, the present invention is an ultrasonic receiving dynamic focus circuit, in which the circuit scale can be made small and there is no switching noise and a dynamic focus circuit close to ideal can be constructed. The purpose is to provide a circuit.

[0015]

FIG. 1 is a block diagram showing the principle of the present invention. The above problems can be solved by the ultrasonic receiving dynamic focus circuit configured as follows.

In an ultrasonic diagnostic apparatus having a mechanism for electronically focusing by inputting an ultrasonic pulse for driving each probe with a time delay to a transducer in which a plurality of probes are arranged in an array, A circuit for dynamically changing the delay of the ultrasonic reception signal received by each probe () is provided with a delay line 1 with taps for each probe () and a transistor 2 for each tap 10 collector
(C) is connected, the emitter (E) of the transistor 2 is shared, and a constant current input signal source corresponding to the received ultrasonic signal
3 is input, and the base (B) of each transistor 2 is connected to a base signal generation circuit 4 including a resistor, a capacitor, a diode, and a common diode bias voltage circuit 40, and the base signal generation circuit 4 Is connected to a logic control circuit 5, and a circuit for obtaining a reception ultrasonic signal dynamically delayed from the terminal side of the delay line 1 is provided for each tap switching signal from the logic control circuit 5. It should consist of a plurality of probes ().

[0017]

In other words, in the present invention, each tap of the delay line 1
Connect the collector (C) of transistor 2 to 10, and
The emitters (E) of the plurality of transistors 2 are shared, and the signal to the delay line 1 is a constant current output.

The received ultrasonic signal is input to the base (B) of the transistor 30, which constitutes this constant current output source, and the constant current output corresponding to the received ultrasonic signal is supplied to the transistor 2 Supply to the emitter (E) of.

Also, the bases of the plurality of transistors 2
In (B), the logic control circuit 5 generates and inputs a signal that is at the “H” level for the required timing and the required period for the required tap 10.

As the base input signal, for example, a transistor transistor logic (TTL) level logic signal generated by the logic control circuit 5 is input to the base signal generation circuit 4, and the base signal generation circuit 4 receives the logic signal. When input to an integrator circuit that is provided and consists of a normal resistor (R) and capacitor (C), the period "H" is short after the tap switching base signal whose period "H" is long, as will be described later. When the tap switching base signal comes, the integration signal of the tap switching base signal having a short period “H” is buried in the integration signal of the tap switching base signal having a long period “H”. ,
By clamping the integrated signal with a diode and two types of diode bias voltages (V1, V2), the period "H" of the base input signal is the same whether the period "H" is long or short. A base signal proportional to H ″ can be input to the transistor 2.

Therefore, with a simple circuit, the switching noise is small, the impedance change in the delay line 1 is small, and the base signal proportional to the tap switching period "H" regardless of the length of the tap switching period "H". Is the base of transistor 2 (B) connected to each tap 10.
Can be input to the ultrasonic reception signal, and the ultrasonic reception signal can be provided with a delay close to ideal, and by providing a plurality of this circuits for each probe, ultrasonic reception dynamic focus can be realized and higher quality There is an effect that an ultrasonic image can be obtained.

[0022]

Embodiments of the present invention will now be described in detail with reference to the drawings. The above-mentioned FIG. 1 is a principle configuration diagram of the present invention, and FIG.
FIG. 5 is a diagram showing an embodiment of the present invention, and FIG.
3 shows an example of the output waveform of the logic control circuit, FIG. 3 shows an example of the configuration of the base signal generation circuit, FIG. 4 shows an example of the base signal generation, and FIG. 5 shows a switching signal from tap 1 to tap 2. Shows an example of generation of.

In the present invention, an ultrasonic diagnostic apparatus is provided with a transducer in which a plurality of probes are arranged in an array, and a mechanism for delaying ultrasonic pulses for driving each probe by time to perform electronic focusing. In Fig. 2, a circuit that dynamically changes the focus point of ultrasonic wave reception is provided by connecting the collector (C) of the transistor 2 to the tapped delay line 1 and each tap 10 for each probe. The source (B) of each transistor 2 is connected to a resistor, a capacitor, a diode and a common source by inputting the signal source 3 of the constant current input corresponding to the received ultrasonic signal. A base signal generation circuit 4 consisting of a diode bias voltage circuit 40 is connected, and a logic control circuit 5 is connected to the base signal generation circuit 4 to configure this circuit for each probe. Plurality providing means Te is a means necessary for carrying out the present invention. The same reference numerals denote the same objects throughout the drawings.

The operation of the configuration of the ultrasonic receiving dynamic focus circuit of the present invention will be described below with reference to FIGS. 2 to 5 with reference to FIG. First, in the ultrasonic receiving dynamic focus circuit of the present invention, the collector (C) of the transistor 2 is connected to the tapped delay line 1 and the tap 10 for each circuit for each probe, The emitter (E) of the transistor 2 is made common, and the constant current input signal source 3 corresponding to the received ultrasonic signal is input, and the base (B) of each transistor 2 has a resistor, capacitor, diode, common A base signal generation circuit 4 composed of an integrated diode bias voltage circuit 40 is connected, and a logic control circuit 5 is connected to the base signal generation circuit 4.

In order to perform dynamic focusing in the ultrasonic diagnostic apparatus, as described above, the electronic focusing mechanism, that is, the ultrasonic transducers for driving the respective transducers of the transducer in which a plurality of the transducers are arranged in an array. It is necessary to delay the sound wave pulse by time, and further, at the time of reception, give a time delay to each probe for the reception focus point.

Therefore, the signal source 3 for inputting the constant current source, which is composed of the transistor 30, is provided, and the base (B) is driven by the received ultrasonic signal to generate the signal source 3 in the constant current mode. be able to.

By controlling the base (B) of the transistor 2 whose emitter input is the signal source 3 of the constant current source input corresponding to the received ultrasonic signal by the tap switching signal from the logic control circuit 5, The generated ultrasonic signal can be delayed.

At this time, each tap (1) to (n) 10 of the delay line 1
On the other hand, as shown in FIG. 2, tap switching signals A having different tap switching periods “H” are input to the base signal generation circuit 4. This is to change the delay amount with respect to the ultrasonic echo signal received by one probe into a change in the focus point as a whole.

If the tap switching signals A1, A2, ... having different tap switching periods "H" are applied to the base (B) of the transistor 2, switching noise is generated as described above.

Therefore, in the present invention, the tap switching signal is integrated with the base (B) of the transistor 2 by the integrating circuit 41 shown in FIG.

At this time, after the tap switching signal A1 having a long tap switching period "H" {corresponding to the tap switching signal of the tap (1) in FIG. 2}, the tap switching signal A2 having a short tap switching period "H" {Fig. Two taps
Corresponding to the tap switching signal of (1)}, the integrated waveform becomes like the solid line and the dotted line of FIG. 4 (a), and the integrated waveform a1 (of the tap switching signal A1 having a long tap switching period “H” ( (Indicated by a solid line) indicates an integrated waveform a of the tap switching signal A2 having a short tap switching period "H" thereafter.
It happens that 2 (indicated by the dotted line) is buried.

Therefore, in the present invention, a diode circuit is provided after the integration circuit 41 of the base signal generation circuit 4.
By providing the clamp circuit 40 composed of 400 and the diode bias voltage circuit 401, the integrated waveform a1 shown in FIG. 4 (b) becomes the tap shown in FIG. 2 as shown in FIG. 4 (b). The integration operation starts and ends at the rising and falling timings of the switching signal.
You can shift up by 1 to get a trapezoidal waveform clamped at voltage V2.

Therefore, as shown in FIGS. 4 (c) and 5, the tap switching signal A1 having a long tap switching period "H".
The integrated waveform a1 (shown by a dotted line) of the tap switching signal A2 having a short tap switching period "H" thereafter is not buried in the integrated waveform a1 (shown by a solid line) of
The tap signal can be applied to the base (B) of transistor 2 at the correct timing. However, as shown in FIG. 4 (c), since the switching signal is shaped into a trapezoidal signal and given to the base (B) of the transistor 1, it is possible to reduce the switching noise that has been conventionally generated. it can.

As described above, according to the present invention, in an ultrasonic diagnostic apparatus having a transducer in which a plurality of probes are arranged in an array, a circuit for dynamically changing a focus point of ultrasonic wave reception is provided for each probe. 1 circuit for each, 1 for each
The circuit consists of a delay line with taps, and the collector (C) of a transistor is connected to each tap, and the emitter (E) of the transistor is shared, and a current input signal source corresponding to the received ultrasonic signal is provided. To the base (B) of each transistor, a base signal generation circuit composed of a resistor, a capacitor, a diode, and a common diode bias voltage circuit is connected, and the base signal generation circuit is connected to a logic control circuit. Is connected to the logic control circuit, and the reception ultrasonic signal dynamically delayed from the terminal side of the delay line is obtained according to the tap switching signal from the logic control circuit. The feature is that a plurality of them are provided corresponding to the children.

[0035]

As described above in detail, the ultrasonic receiving dynamic focus circuit of the present invention is capable of detecting ultrasonic waves in an ultrasonic diagnostic apparatus having a transducer in which a plurality of probes are arranged in an array. A circuit that dynamically changes the focus point is provided for each probe,
Each circuit consists of a delay line with taps, and the collector (C) of a transistor is connected to each tap, and the emitter (E) of the transistor is shared, so that the current input corresponding to the received ultrasonic signal is A signal source is input, and a base signal generation circuit consisting of a resistor, a capacitor, a diode, and a common diode bias voltage circuit is connected to the base (B) of each transistor. A control circuit is connected and configured to obtain a reception ultrasonic signal dynamically delayed from the terminal side of the delay line in response to a tap switching signal from the logic control circuit. Since a plurality of probes are provided corresponding to the probe, the circuit is simple and has less switching noise, and the tap switching period is "H".
Regardless of the length of the tap switching period, a base signal proportional to the tap switching period "H" can be input to the base (B) of the transistor 2 connected to each tap 10, and a delay close to ideal can be received with ultrasonic waves. By providing a plurality of circuits corresponding to each probe, reception dynamic focusing can be realized and a higher quality ultrasonic image can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of the principle of the present invention.

FIG. 2 is a diagram showing an embodiment of the present invention (No. 1).

FIG. 3 is a diagram showing an embodiment of the present invention (part 2).

FIG. 4 is a diagram showing an embodiment of the present invention (part 3).

FIG. 5 is a diagram showing an embodiment of the present invention (No. 4).

FIG. 6 is a diagram showing the principle of electronic focusing.

FIG. 7 is a diagram showing the principle of dynamic focus (No. 1).

FIG. 8 is a diagram showing the principle of dynamic focus (No. 2).

FIG. 9 is a diagram illustrating a conventional ultrasonic receiving dynamic focus circuit.

[Explanation of symbols]

1 Delay line 10 Taps 2,30 Transistor 3 Constant current input signal source 4 Base signal generation circuit 40 Clamp circuit 400 Diode circuit 401 Diode bias voltage circuit 41 Integration circuit 5 Logic control circuit Transducer

Claims (1)

[Claims] 1. A mechanism provided with a transducer for arranging a plurality of probes () in array form, for inputting an ultrasonic pulse for driving each probe () with a time delay and performing electronic focusing. In ultrasonic diagnostic equipment, each probe
A circuit for dynamically changing the delay of the ultrasonic received signal received by () is provided for each probe () with a delay line (1) with taps and a transistor (2) for each tap (10). ) Is connected to the collector (C), the emitter (E) of the transistor (2) is shared, and the signal source (3) of constant current input corresponding to the received ultrasonic signal is input to each transistor (2). A base signal generation circuit (4) consisting of a resistor, a capacitor, a diode, and a common diode bias voltage circuit (40) is connected to the base (B) of each of the base signal generation circuit (4). Logic control circuit
(5) is connected to form a circuit for obtaining a reception ultrasonic signal dynamically delayed from the terminal side of the delay line (1) in response to the tap switching signal from the logic control circuit (5), An ultrasonic receiving dynamic focus circuit comprising a plurality of units provided for each probe ().