JP3822820B2 - Ultrasonic diagnostic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to a receiving circuit that processes a plurality of received signals.
[0002]
[Prior art and problems]
In the ultrasonic diagnostic apparatus, a plurality of reception signals output from a plurality of vibration elements are input to a reception circuit. The reception circuit includes a preamplifier, a gain variable amplifier, an A / D converter, and the like provided for each channel, and further includes a phasing addition circuit that adjusts and adds phases of a plurality of reception signals. The received signal after the phasing addition is input to the image forming circuit via a circuit such as a band pass filter, for example.
[0003]
Incidentally, when performing harmonic imaging (harmonic imaging), it is necessary to extract a desired band component from the received signal. Therefore, conventionally, a band pass filter is provided after the receiving circuit, that is, after phasing addition, and its center frequency and the like are varied.
[0004]
However, when the receiving circuit is configured as a digital beam former, that is, when the received signal of each channel is digitally converted before the phasing addition, the received signal is considered in consideration of the input dynamic range of the A / D converter. It is necessary to adjust the gain. In this case, the range of the entire received signal is matched to the input dynamic range of the A / D converter regardless of the range of the target frequency component that is finally required. There is a problem that the ratio cannot be improved.
[0005]
In particular, in recent years when harmonic imaging has been put into practical use, it is desired to extract harmonic components more effectively. However, harmonics are considerably weaker signal components than the fundamental wave, and the level of the fundamental wave is A. If the input dynamic range of the / D converter is adjusted, a sufficient dynamic range cannot be secured for the harmonics.
[0006]
The present invention has been made in view of the above conventional problems, and an object of the present invention is to make it possible to adjust a dynamic range by extracting a target component prior to A / D conversion for each channel.
[0007]
Another object of the present invention is to easily align the passband characteristics of a bandpass filter between channels.
[0008]
Another object of the present invention is to improve the image quality of ultrasonic images (particularly harmonic imaging images).
[0009]
[Means for Solving the Problems]
(1) In order to achieve the above object, the present invention provides an ultrasonic diagnostic apparatus that inputs and processes a plurality of reception signals output from a plurality of vibration elements, thereby forming an ultrasonic image. A plurality of band-pass filters individually provided for each vibration element and a phasing addition for the received signals that are provided after the plurality of band-pass filters and pass through the plurality of band-pass filters. A plurality of bias generators that are provided corresponding to a plurality of bandpass filter groups set for the plurality of bandpass filters and to supply a bias signal for each group to be supplied to each bandpass filter group. And a control unit that adjusts pass band characteristics of the plurality of band pass filters for each group .
[0010]
According to the above configuration, the received signal is input to the phasing addition circuit via the band pass filter. The passband characteristics of each bandpass filter are set so as to extract components necessary for forming an ultrasonic image. Actually, when there is a difference in the passband characteristics (especially the resonance point) of each bandpass filter due to variations (or other factors) in the operation characteristics of the elements constituting each bandpass filter. There can be. According to the above configuration, since the passband characteristic can be adjusted for each group in response to such variations (for example, it can be made uniform), the image quality of the ultrasonic image can be improved. In the above adjustment, in addition to fine adjustment of the pass band characteristic, switching of the pass band characteristic (for example, switching between fundamental wave extraction and harmonic wave extraction) may be performed. The adjustment can be performed manually or automatically as needed, at the time of shipment and maintenance of the apparatus.
[0011]
Preferably, the control unit is between Band-pass filter group, performs control to align the pass band characteristic. Adjustments can be made for each bandpass filter for more ideal adjustments, and adjustments between each bandpass group simplify the circuit configuration for adjustment while obtaining a certain adjustment effect. it can.
[0012]
By the way, devices manufactured adjacently in the manufacturing stage (especially variable capacitance diodes) have the same operating characteristics. Therefore, in order of channel number, in consideration of the manufacturing order of devices. It is desirable to select an element to be used in the circuit configuration. On the premise of such an arrangement, it is desirable to perform adjustment for each bandpass group.
[0013]
Preferably, each bandpass filter extracts a harmonic component from the received signal in a harmonic imaging mode. According to this configuration, a harmonic component is extracted from the received signal, and a B-mode image or the like can be created using the harmonic component.
[0014]
Preferably, each of the bandpass filters is provided in the front stage of the A / D converter. According to this configuration, since the bandpass filter is provided in the front stage of the A / D converter, the input dynamic range of the A / D converter can be effectively used for the harmonic component, and the image quality of the ultrasonic image can be improved. Enhanced.
[0015]
Preferably, switching means for switching whether to pass each received signal through each bandpass filter or to bypass it is included. According to this configuration, for example, when an ultrasonic image is formed with a fundamental wave (fundamental mode), a bandpass filter is used, while in a harmonic imaging mode, a received signal is input to the bandpass filter.
[0016]
Preferably, each of the bandpass filters includes a resonance circuit including an inductor element and a capacitor element, the capacitor element includes at least one diode to which a reverse bias voltage is applied, and the control unit outputs the reverse bias voltage. The pass band characteristic of each of the band pass filters is adjusted by varying it. According to this configuration, the capacitance can be varied by varying the reverse bias voltage of the diode, and the passband characteristics can be adjusted by a simple technique of varying the voltage.
[0017]
Further, the present invention provides an ultrasonic diagnostic apparatus that inputs and processes a plurality of reception signals output from a plurality of vibration elements, thereby forming an ultrasonic image, and is provided individually for each of the vibration elements. A plurality of bandpass filters, a phasing addition circuit that is provided in a subsequent stage of the plurality of bandpass filters, and that performs phasing addition on a received signal that has passed through the plurality of bandpass filters, and each bandpass A control unit that adjusts a passband characteristic of the filter, and each bandpass filter includes a resonance circuit including an inductor element and a capacitor element, and the capacitor elements are reversely directed to each other, to which a reverse bias voltage is applied. The control unit varies a reverse bias voltage for each of the pair of diodes. According to this configuration, since the pair of diodes are connected in the opposite direction, a sufficient capacitance can be formed while compensating for the characteristic variation in a complementary manner.
[0018]
(2) In order to achieve the above object, the present invention provides an ultrasonic diagnostic apparatus that inputs and processes a plurality of reception signals output from a plurality of vibration elements, thereby forming an ultrasonic image. A plurality of resonance circuits that are provided for each of the vibration elements and include an inductor element and a varicap diode circuit including a pair of varicap diodes connected in opposite directions to which a reverse bias voltage is applied. Set for the plurality of band-pass filters , the phasing addition circuit that is provided in the subsequent stage of the plurality of band-pass filters, and that performs phasing addition on the received signals that have passed through them. provided for each of a plurality of band-pass filter group, a group-specific reverse bias voltage applied to each variable capacitance diode circuits originating was To include a plurality of bias generating circuit, and wherein the respective bias generating circuit can be adjusted by group of the reverse bias voltage generated.
[0019]
According to the above configuration, since adjustment can be performed in units of groups, it is possible to perform adjustment in units of groups for all channels, and it is possible to simplify the circuit configuration and reduce manufacturing costs.
[0020]
(3) Moreover, in order to achieve the said objective, this invention is an ultrasonic transducer | vibrator comprised by the several vibration element which outputs a received signal by transmitting an ultrasonic wave and receiving a reflected wave. When a plurality of preamplifiers performing pre-amplification to the received signals output from said plurality of transducer elements, a plurality of filters for extracting a harmonic component, the received signal outputted from said plurality of preamplifier input A plurality of filter circuits, a plurality of variable gain amplifiers for amplifying the reception signals output from the plurality of filter circuits, and a plurality of A for converting the reception signals output from the plurality of variable gain amplifiers into digital signals. / D converter, and an image forming circuit for forming a harmonic imaging image based on the converted received signals by said plurality of a / D converter into a digital signal, before Seen containing a display for displaying the harmonic imaging image, said each filter circuit has a resonant circuit composed of an inductor element and a capacitor element, the capacitor element is connected to the opposite directions to reverse bias voltage is applied, respectively The control unit is configured to vary a reverse bias voltage for each of the pair of diodes .
[0021]
According to the above configuration, after the harmonic component is extracted from the received signal, gain adjustment is performed on the received signal, and then the received signal can be input to the A / D converter. Therefore, in the harmonic imaging mode, the input dynamic range of the A / D converter can be effectively utilized by raising the level of the harmonic component (by increasing the gain compared to the case of fundamental wave imaging). As a result, it is possible to detect even signal components at a level that was excluded in the conventional configuration. That is, the signal detection limit can be lowered.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0023]
FIG. 1 shows a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention, and FIG. 1 is a block diagram showing the overall configuration thereof.
[0024]
The probe 10 is an ultrasonic probe that transmits and receives ultrasonic waves. The probe 10 is used in contact with the surface of a living body or inserted into a body cavity. The probe 10 includes an array transducer which will be described later with reference to FIG. 2, and the array transducer is composed of a plurality of transducer elements. An ultrasonic beam is formed by the array transducer, and the ultrasonic beam is electronically scanned. Examples of the electronic scanning method include electronic linear scanning and electronic sector scanning.
[0025]
The transmission unit 12 functions as a transmission beam former, and a transmission signal is supplied from the transmission unit 12 to each vibration element constituting the array transducer.
[0026]
The reception unit 14 functions as a reception beam former and is a circuit that performs phasing addition processing on a plurality of reception signals output from a plurality of vibration elements. The specific circuit configuration will be described later with reference to FIG. 2. In this embodiment, a band pass filter (BPF) is provided for each channel, and the pass band characteristics of each BPF are variable or adjusted. Can do.
[0027]
The controller 16 controls the operation of each component in the apparatus, and an input unit 18 constituted by an operation panel or the like is connected to the controller 16.
[0028]
The signal processing unit 20 is a circuit that performs signal processing for tomographic image formation, signal processing for Doppler image formation, and the like. An ultrasonic image is formed by this signal processing, and the image information is output to the display unit 24 via the display processing unit 22. Various images such as a B mode and a color flow mapping image are displayed on the display unit 24 as an ultrasonic image.
[0029]
The ultrasonic diagnostic apparatus according to the present embodiment has a so-called harmonic imaging mode in addition to an image forming function using a normal fundamental wave. In this harmonic imaging mode, a harmonic component contained in the received signal is extracted, and an ultrasonic image is formed using the harmonic component. In that case, the harmonics are extracted by the receiving unit 14 shown in FIG.
[0030]
FIG. 2 shows a specific configuration example of the receiving unit 14 shown in FIG.
[0031]
As described above, the array transducer 30 includes the plurality of vibration elements 32.
[0032]
The receiving unit 14 roughly includes a preamplifier group 34, a BPF group 38, a variable gain amplifier group 44, an A / D converter group 48, a delay line (DL) group 52, an adder 56, and the like. Here, the delay line group 52 and the adder 56 constitute a so-called phasing adder 51.
[0033]
As shown in FIG. 2, the preamplifier group 34 includes a preamplifier 36 provided for each channel. Similarly, the BPF group 38 includes a BPF 40 provided for each channel, and a variable gain amplifier 44. Is constituted by a variable gain amplifier 46 provided for each channel, the A / D converter group 48 is constituted by an A / D converter 50 provided for each channel, and the DL group 52 is provided for each channel. It is comprised by provided DL54.
[0034]
Here, focusing on one channel, the reception signal output from the vibration element 32 is amplified by the preamplifier 36, and then the reception signal is input to the BPF 40. Then, after filtering the received signal in the BPF 40, the received signal as the output signal is input to the gain variable amplifier 46. The variable gain amplifier 46 is a circuit that performs desired amplification on the received signal, and the amplified received signal is converted into a digital signal by the A / D converter 50. The received signal converted into the digital signal is subjected to delay processing in the DL 54, and the delayed received signal is output to the adder 56. That is, the adder 56 adds a plurality of reception signals that have been subjected to predetermined delay processing, thereby outputting the reception signal after the phasing addition to the subsequent stage.
[0035]
In the present embodiment, a plurality of groups 42 are set for a plurality of BPFs 40 constituting the BPF group 38. For example, when there are channels 0 to N, n BPFs from the 0th side constitute each group 42, and thereby k groups are constituted. In the present embodiment, a bias generator 60 is provided for each group 42 of each BPF 40. That is, each bias generator 60 supplies a control voltage as a bias signal described later to the corresponding group. Each bias generator 60 individually controls the bias voltage in units of groups, so that the passband characteristics for the received signal can be varied or adjusted for each group. With such a configuration, it is possible to improve the image quality of the ultrasonic image by suppressing variations in passband characteristics (particularly the center frequency) of the entire channel within a certain range. In particular, in the harmonic imaging mode, there is an advantage that a desired harmonic component can be extracted more efficiently, and the S / N ratio can be improved to form a good ultrasonic image.
[0036]
In FIG. 2, a bias generator 58 is configured by a plurality of bias generators 60. The reception control unit 62 adjusts the gain for each variable gain amplifier 46 and also controls the delay amount in each DL 54. In the present embodiment, the reception control unit 62 also controls whether or not to switch the passband characteristics in each BPF 40 or to substantially filter the BPF 40 according to the operation mode of the apparatus.
[0037]
In the embodiment shown in FIG. 2, the adjustment of the passband characteristics of each BPF 40 is made in units of groups 42. However, of course, a bias generator 60 is provided for each BPF 40 to individually adjust the passband characteristics. You may make it perform finely.
[0038]
FIG. 3 shows an example of a specific circuit configuration of the BPF 40 shown in FIG. The BPF 40 includes a circuit module 72. In the harmonic imaging mode, the filtered received signal that has passed through the circuit module 72 is selected and output by the selector 74, while in the fundamental imaging mode, the circuit module 72 An unfiltered received signal that bypasses 72 is selected by the selector 74 and output. That is, a bypass line 77 that bypasses the circuit module 72 and outputs the received signal 100 to the subsequent stage is provided. The selector 74 is constituted by an analog switch, for example.
[0039]
The circuit module 72 will be described below. As shown in the figure, the circuit module 72 includes an input transistor Q1, a filter circuit 76, an output transistor Q2, and the like. Here, the filter circuit 76 constitutes a resonance circuit, and includes an inductor element (coil) L and a variable capacitance circuit 70. By varying the capacitance in the variable capacitance circuit 70, the passband characteristic of the BPF 40 is adjusted. The resistor R5 is mainly for adjusting the sharpness (Q value) of the passband characteristic, and the capacitor C2 is provided mainly for DC cutting. A reception signal is input to the variable capacitance circuit 70 through the resistor R5 and the capacitor C2.
[0040]
The variable capacitance circuit 70 forms a varicap diode circuit, and specifically includes a pair of diodes (varicap diodes) D1 and D2 connected in parallel in opposite directions. A control voltage (positive voltage) 104 is applied as a reverse bias voltage to the anode side of the diode D1, and a control voltage (negative voltage) 106 is applied as a reverse bias voltage to the cathode side of the diode D2. Therefore, the voltage between the anode and cathode of each of the diodes D1 and D2 can be varied to a desired value by the control voltage.
[0041]
Here, the control voltages 104 and 106 are generated by the bias generator 60 (FIG. 2) corresponding to the group to which the BPF 40 belongs. As described above, by adjusting the control voltages 104 and 106, the capacitance of the variable capacitance circuit 70 is changed, whereby the passband characteristics (mainly the center frequency) can be adjusted. If the diodes D1 and D2 manufactured adjacently in the manufacturing stage are used, it is possible to obtain a complementary compensating action with uniform characteristics. In particular, for each BPF 40 in the same group, it is desirable to take care to make the characteristics of the diodes as uniform as possible. Of course, when a bias generator is provided for each BPF 40, such consideration is unnecessary. The control voltages 104 and 106 are variably controlled simultaneously or individually.
[0042]
The transistor Q3 provided on the emitter side of the input transistor Q1 constitutes a part of a constant current circuit, and a bias current 102 is input to its base. The value of the bias current 102 is the same between the BPFs 40 and is fixed. However, the value of the bias current 102 can be adjusted for constant current adjustment. It should be noted that a constant current source may be configured using a resistor instead of the transistor Q3.
[0043]
When the received signal 100 is input to the base of the input transistor Q 1, the received signal appears as a voltage at its collector, and the received signal passes through the filter circuit 76. In the process, a signal component of a desired frequency band in the received signal is extracted according to the pass band characteristic of the filter circuit constituting the resonance circuit. In this embodiment, a harmonic component is extracted, and a received signal composed of the component is input to the base of the output transistor Q3. Then, a reception signal appears on the emitter side of the output transistor Q3 and is input to the selector 64 via the DC cut capacitor C3. The resistors R1, R3, R4, R6, R7, and R8 and the capacitors C1, C4, C5, C6, C7, and C8 are for defining circuit operating conditions.
[0044]
The configuration in FIG. 3 is merely an example, and various circuit configurations can be used as long as the passband characteristics can be adjusted by the variable capacitance. When forming an image with a fundamental wave, the center frequency of the passband characteristic may be matched with the frequency of the fundamental wave instead of the detour switching of the received signal 100 with respect to the circuit module 72 described above. According to such a configuration, there is an advantage that unnecessary signal components can be removed and the S / N ratio can be improved. Further, the passband characteristic may be dynamically changed according to the depth of the reception point. Furthermore, when configuring the variable capacitance circuit, only one diode may be used, or a larger number of diodes may be used.
[0045]
【The invention's effect】
As described above, according to the present invention, the image quality of an ultrasonic image can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention.
FIG. 2 is a block diagram illustrating a specific configuration example of a receiving unit illustrated in FIG.
3 is a circuit diagram showing a specific circuit configuration example of the BPF shown in FIG. 2;
[Explanation of symbols]
10 Probe, 12 Transmitter, 14 Receiver, 16 Controller, 20 Signal Processor, 22 Display Processor, 24 Display Unit, 40 BPF, 42 BPF Group, 60 Bias Generator, 62 Reception Controller, 70 Variable Capacitance Circuit, 72 circuit modules, 74 selectors.

Claims (9)

In an ultrasonic diagnostic apparatus that inputs and processes a plurality of reception signals output from a plurality of vibration elements, thereby forming an ultrasonic image,
A plurality of band-pass filters individually provided for each of the vibration elements;
A phasing addition circuit that is provided in a subsequent stage of the plurality of bandpass filters and that performs phasing addition on the reception signals that have passed through the plurality of bandpass filters;
A plurality of bias generation circuits which are provided corresponding to a plurality of bandpass filter groups set for the plurality of bandpass filters and generate bias signals for each group to be supplied to each bandpass filter group; A controller that adjusts the passband characteristics of a plurality of bandpass filters for each group ;
An ultrasonic diagnostic apparatus comprising: The apparatus of claim 1.
Wherein, between Band-pass filter group, an ultrasonic diagnostic apparatus characterized by performing control to align the pass band characteristic. The apparatus of claim 1.
Each of the bandpass filters extracts a harmonic component from a received signal in a harmonic imaging mode. The apparatus of claim 1.
Each of the band-pass filters is provided in front of an A / D converter. The apparatus of claim 1.
An ultrasonic diagnostic apparatus comprising switching means for switching whether each received signal is passed through each bandpass filter or bypassed. The apparatus of claim 1.
Each band-pass filter has a resonance circuit composed of an inductor element and a capacitor element,
The capacitor element includes at least one diode to which a reverse bias voltage is applied;
The ultrasonic diagnostic apparatus, wherein the control unit adjusts a passband characteristic of each bandpass filter by varying the reverse bias voltage. In an ultrasonic diagnostic apparatus that inputs and processes a plurality of reception signals output from a plurality of vibration elements, thereby forming an ultrasonic image,
A plurality of band-pass filters individually provided for each of the vibration elements;
A phasing addition circuit that is provided in a subsequent stage of the plurality of bandpass filters and that performs phasing addition on the reception signals that have passed through the plurality of bandpass filters;
A controller that adjusts the passband characteristics of each bandpass filter;
Including
Each band-pass filter has a resonance circuit composed of an inductor element and a capacitor element,
Each of the capacitor elements is composed of a pair of diodes connected in opposite directions to which a reverse bias voltage is applied,
Ultrasonic diagnostic equipment, wherein the control unit to vary the reverse bias voltage for each of the pair of diodes. In an ultrasonic diagnostic apparatus that inputs and processes a plurality of reception signals output from a plurality of vibration elements, thereby forming an ultrasonic image,
A plurality of resonance circuits that are provided for each of the vibration elements and include an inductor element and a varicap diode circuit including a pair of varicap diodes connected in opposite directions to which a reverse bias voltage is applied. A bandpass filter,
A phasing addition circuit that is provided in a subsequent stage of the plurality of bandpass filters and that performs phasing addition on the received signals that have passed through them;
Provided for each of a plurality of band-pass filter group set for the plurality of band pass filters, and a plurality of bias generating circuit for generating a group-specific reverse bias voltage applied to each variable capacitance diode circuit,
Including
An ultrasonic diagnostic apparatus, wherein a reverse bias voltage for each group generated by each of the bias generation circuits can be adjusted. An ultrasonic transducer composed of a plurality of vibration elements that transmit an ultrasonic wave and receive a reflected wave to output a reception signal;
A plurality of preamplifiers performing pre-amplification to the received signals output from said plurality of transducer elements,
A plurality of filters for extracting harmonic components, a plurality of filter circuits to which received signals output from the plurality of preamplifiers are input;
A plurality of variable gain amplifiers for amplifying received signals output from the plurality of filter circuits;
A plurality of A / D converters for converting received signals output from the plurality of variable gain amplifiers into digital signals;
An image forming circuit for forming a harmonic imaging image based on the received signals converted into digital signals by the plurality of A / D converters;
A display for displaying the harmonic imaging image;
Only including,
Each filter circuit has a resonance circuit composed of an inductor element and a capacitor element,
Each of the capacitor elements is composed of a pair of diodes connected in opposite directions to which a reverse bias voltage is applied,
The ultrasonic diagnostic apparatus, wherein the control unit varies a reverse bias voltage for each of the pair of diodes .

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