JPS63131183A - Waveform display device - 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 Industrial Application) The present invention relates to a waveform display device for displaying signal waveforms on a display means such as a CRT or LCD. The present invention relates to a waveform display device that is effective for displaying the waveform of a signal that includes a mixture of high-frequency components and low-frequency components, such as a waveform such as a waveform such as a signal having a mixture of high-frequency components and low-frequency components.

(Prior Art) FIG. 6 is a phonocardiogram obtained by recording waveforms of heart sound signals using a pen recorder. Conventionally, a phonocardiogram has a signal waveform with low frequency signal components unchanged, as shown in the figure.
It is customary to display the outline of the signal waveform with almost all the high frequency components filled out, in other words, to display a display similar to the waveform recorded by a pen recorder. It is said to be useful.

On the other hand, when displaying a signal waveform on a bitmap type display means such as a CRT or LCD, the bit size is fixed, so when the display speed is determined, the sample rate is also determined. For example, if the dot size in the temporal axis direction of the display means is 11Im and the display speed is 100av/s, then 1
This results in 0.01 seconds per dot, and the sample rate on the display is 100 samples per second. Conversely, if the sample rate is set to 100 samples per second, the display speed is 10
011/S is decided.

(Problem to be solved by the invention) For this reason, depending on the bitmap type display means,
As it is, it is not possible to display a signal waveform as shown in FIG. 6 for a heart sound signal, and there is a problem that it does not fit in with the display style that has been customarily used up to now.

The present invention was made in view of these problems, and
The purpose is to realize a display device that can display waveforms similar to waveform recording by a pen-recorder, in which high frequency components are filled out, although using a bitmap type display means.

(Means for Solving the Problems) FIG. 1 is a block diagram of the basic configuration of the apparatus of the present invention. In the figure, 1 includes frequency component separation means for dividing the signal 01 to be displayed into a low frequency component signal eL and a high frequency component signal eH, and 2 includes a high frequency component signal e.
A detection circuit that performs line detection and smoothing to obtain an envelope waveform signal; 3 is a filling means that inputs the envelope waveform signal eε from the detection circuit 2 and fills in the envelope waveform portion; 4 is a signal eN from the filling means 3; , low frequency component signal e1. a synthesis means for synthesizing
Reference numeral 5 denotes a bitmap type display means for displaying the signal eQ from the combining means 4.

(Function) The bitmap type display means 5 performs normal waveform display (line drawing display) for low frequency component signals, and for high frequency components, the envelope waveform portion is displayed by the filling means 3. A length corresponding to the amplitude is drawn in the amplitude direction of the display, and a filled display is performed. This enables waveform display similar to waveform recording by a pen-layer recorder.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a configuration block diagram showing an example of the apparatus of the present invention. In the figure, the same parts as in FIG. 1 are given the same reference numerals.

In this embodiment, the frequency component separation means 1 includes a bypass filter 11 and a low-pass filter 12. The frequency characteristics of each of these filters 11 and 12 are as follows:
As shown in FIG. 3, the cutoff frequencies fc are selected so that they match, and the total gain of both filters 11 and 12 is made constant with respect to frequency as shown by the broken line. be. Note that the cutoff frequency fc is selected to a predetermined value (for example, fs/4 with respect to the sampling rate "S") corresponding to the sample rate of the time axis displayed on the display means 5.The detection circuit 2 is a diode are connected in parallel with opposite polarities, and a smoothing capacitor.The output of the detection circuit 2 and the output of the low-pass filter 12 are both connected to an A/D converter 61. to perform digital signal processing. 62, where it is converted into a digital signal.The filling means 3 and the combining means 4 use a microprocessor μP and an image display memory ME, and convert the image data read from the image display memory ME into a bit map format. It is configured to be added to the display means 5. Here, the bitmap type display means 5 is a CRT.

In addition to LCDs and plasma displays, thermal printers, inkjet printers, etc. are used.

The operation of the apparatus configured as described above will be explained as follows with reference to the operational waveform diagram of FIG. 4.

It is now assumed that, for example, a heart sound signal Gj including a low frequency component and a high frequency component as shown in FIG. 4(A) is input to the input terminal 10. In the frequency component separation means 1,
The low-pass filter 12 passes only the low frequency components of the heart sound signal e1 and outputs a signal eL as shown in (B), and the bypass filter 11 passes only the high frequency components of the heart sound signal e1, and (C) A signal e as shown in is output. This high frequency component signal e is detected by the detection circuit 2 and becomes an envelope waveform signal eε as shown in (d). Low frequency component signal eL and envelope waveform signal eε
are converted into digital signals by A/D converters 62 and 61, respectively, and applied to the microprocessor μP. Here, the envelope waveform signal is filled in, and a low frequency component signal is synthesized with it. Then, a composite display waveform signal eo as shown in (E) is created.

The filling process by the microprocessor μP is a process in which filling is performed with a line segment whose length is, for example, twice the amplitude of the envelope waveform signal eE, and is realized by software.

The composite signal produced by the microprocessor μP is
The signal is temporarily stored in the image memory ME and read out to the display means 5, where a waveform display similar to an analog display as shown in FIG. 6 is performed.

In addition, in microprocessor μP, filling processing using line segments generally takes more time than simple line drawing. Therefore, in areas where there are many high frequency components, move the time axis a little and draw the time slightly earlier than the latest time, and when the high frequency components decrease, the time will be drawn to match the latest time. Other signal processing may also be performed.

FIG. 5 is a block diagram showing another embodiment of the device of the present invention. In this embodiment, two A/Ds are shown in FIG.
The converter is one A/D converter 60, which is switched and used by a multiplexer MPX. In this case, it is assumed that the conversion time of the A/D converter 60 is sufficiently short compared to the lean pull rate of the display means 5.

According to this embodiment, compared to the apparatus shown in FIG. 2, not only one A/D converter is required, but also the A/D conversion characteristics on the high frequency component side and the low frequency component side are the same, so that Display errors caused by uneven /D conversion characteristics can be eliminated.

(Effects of the Invention) As described above in detail, according to the present invention, when displaying a signal waveform on a bitmap display means in which the dot size in the time axis direction is determined, the frequency that can be displayed at the sample rate determined by the dot size is Even for signals with higher frequency components, analog display similar to waveform recording by a Ben-1 recorder can be performed.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration block diagram of the device of the present invention, FIG. 2 is a configuration block diagram showing an example of the device of the present invention, FIG. 3 is a characteristic diagram of the bypass filter and low-pass filter in FIG. 2, and FIG. 2 is an operational waveform diagram of the apparatus, FIG. 5 is a block diagram showing another embodiment of the apparatus of the present invention, and FIG. 6 is a phonocardiogram in which the waveforms of heart sound signals are recorded by a pen recorder. 1... Frequency component separation means 2... Detection circuit 3... Filling means 4...
・Synthesis means 5...Display means Patent applicant: Yokogawa Medical Systems Co., Ltd. Figure 1] Figure 2

Claims (1)

[Claims] A frequency component separation means for dividing a signal to be displayed into a low frequency component signal and a high frequency component signal, a detection circuit that performs envelope detection and smoothing of the high frequency component signal to obtain an envelope waveform signal, and an envelope waveform signal. a filling means for inputting and filling out the envelope waveform part, a synthesizing means for synthesizing the filling signal from the filling means and the signal of the low frequency component, and a bitmap method for displaying the signal from the synthesizing means. A waveform display device consisting of a display means.