JPS5873339A - Circuit for treating cardiac acoustic signal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to the field of the present invention, which is used to detect heart sounds, such as when simultaneously recording a phonocardiogram as a reference signal when recording ultrasonic V-mode images on a line scan recorder. The present invention relates to a heart sound signal processing circuit for obtaining a recording display signal from a heart sound signal when the signal is scanned and recorded or displayed.

l Prior art and its problems Conventional circuits used for this type of purpose, for example, PPM (pulse position quality tS>circuit line) for recording phonocardiograms, as shown in FIG. The heart sound signal obtained is amplified by amplification a2, inputted to a comparator S, and compared with the sawtooth wave voltage of the sweep signal of the line scan recorder d inputted to the sweep signal input terminal 4. This output signal is At pulse generation #s5, the signal is converted into a luminance signal with a constant pulse width and input to the line scan recorder 6.

According to this circuit, the heart sound signal 81 is directly compared with the sweep signal 82 as shown in FIG. Figure 2 (1)) K Schematically, the output pulse waveform 83 of the pulse generator 6 is very rough (as shown in Figure 2 (C), which shows the displayed waveform of the line scan recorder 6).
This has the disadvantage that the recorded waveform becomes unclear.

(3) Purpose of the Invention The present invention utilizes the fact that the envelope of the heart sound signal is vertically symmetrical to return a recording/display signal for scanning recording or display from the heart sound signal. It is an object of the present invention to provide a heart sound signal processing circuit capable of obtaining clear recorded and displayed waveforms even when the difference is small.

(4) Configuration of the Invention The present invention includes a first envelope extraction circuit that extracts a positive envelope component of a heart sound signal, and a first comparator that compares the output of the tenth envelope extraction circuit with a display/recording sweep signal. a second envelope extraction circuit that extracts a negative envelope component of the heart sound signal; a second comparator that compares the output of the second envelope extraction circuit with the display/recording sweep signal; 1. It is equipped with a signal synthesis circuit that extracts the mismatched portion of the output of the second comparator, and is characterized by being able to clearly and accurately record the envelope components of the heart sound signal necessary for understanding the phonocardiogram. .

φ) Examples of the invention FIG. 3 shows a circuit configuration of an embodiment of the present invention.

In addition, FIG. 4 shows the tie ζ blowfish of the waveform of each person's appearance in the expanded implementation.

In FIG. 3, when a heart sound signal as shown in FIG. 4(a) is input to the input terminal 1, it is amplified by the amplifier 2, and a first envelope extraction circuit 1 extracts a positive envelope as a signal 81. , is input to the second envelope extraction circuit 8 which extracts the negative envelope. These envelope extraction circuits 7.8 output envelope signals such as 84 and 85 in FIG. 4(b), respectively.

These envelope signals S4 and 5sFi are input to the first and second comparators 9 and 101, respectively, and compared with the sweep signal 82 of FIG. 4(b), and the pulse signals s6 and 5sFi shown in FIG. 4(C), respectively, are input. Output as sy.

That is, first, the first comparator 9 receives an envelope signal 84 as shown in the figure, and the first comparator 9 receives the envelope signal 84 as shown in the figure.
Envelope signals 85 as shown in the figure are input to one input terminal at the same time. On the other hand, a sweep signal 82 as shown is input as a reference voltage to the other input terminals of the first and second comparators 9 and 10, respectively. This sweep signal 82 is the same signal as the sweep signal for the travel distance of the line scan recorder 60. Here, the outputs of the comparators 9 and 10 when the person sweeps in FIG. 4(b) are 8 in FIG. 4(C).
6 and S7 are output with the same tie construction. This is because the voltages of the envelope signals S4 and 85 are the same Ov. In addition, during the sweep of OB in FIG. 5(b), pulses are output in a tied pattern like the part B of 86.87 in FIG. 2(c). This is output as the voltage of envelope signals S4 and 85.

In this way, the first and second comparators 9 and 10 generate a 2's pulse train 86. as shown in FIG. 4(C) as pulses corresponding to the sweep of A to H in FIG. S7 will be output.

Pulses 86. output from the first and second comparators 9 and 10. It is input to the exclusive off circuit j611 as the S7f-J1 synthesis circuit, and is shown in FIG. 4(d).
The luminance signal 88 is then sent to the line scan recorder 6 and recorded as shown in FIG. 4(e).

In this way, the envelope of one heart sound signal is divided into a positive first envelope signal S4 and a negative second envelope signal S4.
6 and compare each with the sweep voltage 8z of the line scan recorder 6. A pulse signal based on the comparison result is input to the exclusive OR circuit 11, and the exclusive OR is taken to output the luminance signal 88 to the line scan recorder. 6" and record it. 21st! You can record a rough and unclear recorded waveform like Z (c) as a vertically symmetrical and clear waveform that is faithful to the heart sound waveform. .

5 and 6 show examples of the physical configuration of the portion from the envelope extraction circuit 0.8 to the exclusive OR circuit 11 in the block diagram shown in FIG.

In Figure 5, operational amplifiers ICx,
cz diode D1aD2, wy capacitor C1, resistor RZ
The first one uses full-wave rectification and integral smoothing to extract the positive
This is the envelope extraction circuit 7. The operational amplifier IC3 constitutes a second envelope extraction circuit 8 that inverts the positive envelope signal obtained by the first envelope extraction circuit 7 and extracts a negative envelope.

(In this case, the positive envelope is inverted instead of extracting the direct eclipse envelope from the dilatation sound signal 81.) In FIG. 6, the positive envelope signal s4, the negative envelope signal 85, and the sweep signal The outputs of the first and second comparators 9 and 1o, which respectively compare 82, are applied to an exclusive OR circuit 11 consisting of exclusive OR gates EO1 and Eo2, an OR gate OR1, a capacitor C2, and a resistor R2. Note that the circuit consisting of resistor R1, capacitor c2, and OR gate 0RX-bh receives signals 84.
This is for recording by creating a pulse with a pulse width of a certain culm when the voltage of B5 is the same voltage (heart sound signal 0.I line portion).

Note that the present invention is not limited to the embodiments described above and shown in the drawings, but without changing the gist thereof, a modulation circuit 12 is added to the output of the exclusive OR circuit XI to adjust the density of the recorded waveform. It is adjustable.

This conversion circuit 12 is composed of an AND gate ANDZ, a pulse oscillator 0BCI such as a clock pulse generator, and a volume VRI for adjusting the output bell rate of this pulse oscillator 08C1. The clock pulse occurs during the pulse period of output 88 of ORJ. (
(You can also make it occur all the time). By adjusting the pulse rate, the recording density can be changed as shown in FIGS. 8(a) and 8(b).

(6) Effects of the invention Clear recorded and displayed waveforms can be obtained even when the frequency difference between the heart sound signal and the comparison sweep signal is small.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an example of conventional feeding equipment, FIG. 4(a) to (θ) are diagrams showing the waveforms of each part of the same collision JIIN, and FIGS. 5 and 6 are circuit configuration diagrams showing the specific configuration of the main parts of the same embodiment, FIG. 7 is a circuit configuration diagram showing the main part configuration of another embodiment of the present invention, and FIGS. 8(a) and (b)
) is the recording wave needle diagram. 1... Input terminal, 2... Amplifier, 4... Sweep signal input terminal, 6... Line scan recorder, 7゜8.
- Envelope extraction circuit, 9.10 - Comparator, 1
1-... Exclusive OR circuit. Figure 1--(c) sw. Figure 3 □ Width (b) (c) Figure 5 Figure 7 (a) (b)

Claims (2)

[Claims] (1) A first envelope extraction circuit for extracting a positive envelope component of the heart sound signal, which is attached to a heart sound signal processing circuit for obtaining a recording display signal from the heart sound signal in order to scan and record or display the heart sound signal; a first comparator that compares the output of the envelope extraction circuit with a display/recording sweep signal; a second envelope extraction circuit that extracts a negative envelope component of the heart sound signal; and an output of the second envelope extraction circuit. a second comparator for comparing the display/recording sweep signal;
A heart sound signal processing circuit comprising: a signal synthesis circuit for extracting a mismatched portion of the outputs of the comparators. (2) The heart sound signal processing circuit according to claim 1, wherein the signal synthesis circuit includes a circuit that intermittents the mismatched partial signals and changes the average value of the effective signal. 2. The heart sound signal processing circuit according to claim 1, wherein the tone signal synthesis circuit includes a circuit that makes the level of the mismatched partial signal variable.