JPH11267108A - Portable type electrocardiograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable inexpensive and better recording of signals. SOLUTION: Electrodes 11-1-11-4 are connected to an amplifier part 12 and mounted on a living being. Sensor signals S1-S4 are obtained as low frequency signal of multiple channels from the amplifier part 12. The signals S1-S4 are sequentially selected by a signal selector 13 and each of the signals is converted to a digital data signal Da by an A/D conversion part 14 to be stored into a memory 16. When the volume of the data signal Da stored in the memory 16 reaches a specified value, a mini disc 30 or the like is driven while a specified volume of the data signal Da is read out of the memory 16 to be recorded into the mini disc 30. Hence, the signals can be stored better. This intermittent recording enables prolonged recording without using any large capacity battery. The use of the mini disc allows miniaturization. This also enables borrowing of parts of optical disc devices for recording audio signals and data signals thereby achieving an inexpensive production.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a portable electrocardiograph. Specifically, it is assumed that an analog low-frequency signal detected using a plurality of electrodes is converted into a digital data signal and stored in the data storage means, and when a predetermined amount of data signal is stored in the data storage means, The optical disk is driven by the signal recording means, and the data signal stored in the data storage means is recorded on the optical disk.

[0002]

2. Description of the Related Art Conventionally, an electrocardiograph for recording an action potential generated when a heart beats is used for examining cardiac function. The electrocardiograph amplifies the action potential generated by the pulsation of the heart, and records the obtained signal. Diagnosis such as arrhythmia or myocardial disorder is performed by the signal recorded on the electrocardiograph .

Here, in order to examine the frequency of occurrence of arrhythmia and the like, the heartbeat of the heart is monitored for a long time using a portable electrocardiograph. This portable electrocardiograph uses a cassette tape as a recording medium, and a waveform is recorded on the cassette tape as an analog signal. In addition, the tape can be recorded for a long time by reducing the tape traveling speed. Further, a portable electrocardiograph that uses a semiconductor storage element as a recording medium and records a waveform as a digital signal is also known. Such a portable electrocardiograph is operated using a battery in order to make it portable.

[0004]

By the way, in a portable electrocardiograph which records a waveform on a cassette tape as an analog signal, the recording / reproducing of the signal causes deterioration of S / N. Also, wow and flutter may occur due to uneven tape running speed. When the signal-to-noise ratio deteriorates and wow and flutter occur, signal resolution and reliability deteriorate. Further, since the tape traveling speed is reduced, the tape driving mechanism becomes complicated and expensive. Furthermore, since the battery is driven continuously for a long period of time, a large-capacity battery must be used, and an expensive long-life motor must be used for the tape running motor. Also, since a cassette tape is used, if the cost of a portable electrocardiograph is reduced by diverting the magnetic head or the like of an audio cassette tape recorder, signals of at most four channels can be recorded. Can not.

Further, a portable electrocardiograph using a semiconductor storage element as a recording medium requires a semiconductor storage element with a large storage capacity if it records signals for a long time and with high resolution. Therefore, the portable electrocardiograph becomes expensive. Furthermore, when the battery of the portable electrocardiograph is exhausted, or when the semiconductor storage element is made unitary and removable, and this unitized semiconductor storage element is removed from the portable electrocardiograph, the data is stored. If a nonvolatile memory is used as the semiconductor storage element so that data is not lost, the portable electrocardiograph becomes more expensive.

Accordingly, the present invention provides a portable electrocardiograph which is inexpensive and can record signals well.

[0007]

SUMMARY OF THE INVENTION A portable electrocardiograph according to the present invention comprises an optical disk and a signal for converting a plurality of channels of analog low-frequency signals detected using a plurality of electrodes into digital data signals. Conversion means, data storage means for storing the data signal obtained by the signal conversion means, and data storage means for driving the optical disc when the data amount of the data signal stored in the data storage means reaches a predetermined amount. Signal recording means for recording the data signal stored in the optical disk on the optical disk.

In the present invention, analog low-frequency signals of a plurality of channels detected using a plurality of electrodes are converted into digital data signals and stored in data storage means. When a data signal for a predetermined time is stored in the data storage means, for example, the mini disk is driven by the signal recording means, and the data signal for the predetermined time stored in the data storage means is recorded on the mini disk.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a portable electrocardiograph according to the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a configuration of a portable electrocardiograph 10, in which, for example, a mini disk 30 is used as a recording medium. In FIG. 1, electrodes 11-1 to 11-4 are electrodes for detecting an action potential generated by a heartbeat. These electrodes 11-1 to 11-4 are connected to the amplifier section 12, and are attached to predetermined positions of the living body.

The amplifier section 12 is configured using a differential amplifier to reduce in-phase noise. The amplifier unit 12 amplifies a potential difference of, for example, several mV generated between this reference electrode and another electrode with reference to any one of the electrodes, or a neutral point provided artificially. Amplifying the potential difference generated between the characteristic point and the electrode is performed. The plurality of sensor signals S1 obtained by the amplifier 12
S4 are supplied to the signal switch 13.

The signal switch 13 is connected to an amplifier 1 based on a control signal CS from a system controller 25 described later.
2 are sequentially selected from the sensor signals S1 to S4.
The sensor signal Sa selected by the signal switch 13 is A /
It is supplied to the D conversion unit 14.

The A / D converter 14 converts the supplied analog sensor signal Sa into a digital sensor data signal Da.
Convert to This sensor data signal Da is supplied to the memory controller 15.

A memory 16 for temporarily holding the sensor data signal Da is connected to the memory controller 15. Here, when the sensor data signal Da is supplied from the A / D converter 14 to the memory controller 15, the memory controller 15 receives the supplied sensor data signal Da.
Is supplied to the memory 16 and stored. When the data amount of the sensor data signal Da stored in the memory 16 has reached a predetermined data amount, the memory controller 15 reads the stored sensor data signal Da from the memory 16 and supplies the read sensor data signal Da to the signal processing unit 17.

The signal processing unit 17 converts the supplied sensor data signal Da into, for example, EFM (Eight to Fourteen Modulatio).
n) Modulate and CIRC (Cross Interleave Reed-S
olomon Code) to perform encoding for error correction. The sensor data signal Da that has been subjected to the EFM modulation and the error correction processing is supplied to the recording head 20 as a recording data signal WS. The operations of the A / D converter 14, the memory controller 15, and the signal processor 17 are controlled based on a control signal CS from a system controller 25 described later.

The recording head 20 generates a magnetic field based on the supplied recording data signal WS. This recording head 20
Is applied to the mini-disc 30. At this time, the mini-disc 30 is rotated at a predetermined speed by the spindle motor 21, and the mini-disc 30 to which the magnetic field is applied is irradiated with a predetermined amount of laser light from an optical pickup 22 described later. Therefore, the direction of magnetization at the position irradiated with the laser beam is set to the direction corresponding to the magnetic field, and the recording data signal WS is recorded on the mini disc 30.

The optical pickup 22 irradiates a laser beam onto the mini-disc 30 and controls a servo control unit 2 to be described later.
Focus control and tracking control for condensing the laser light at a desired position on the mini-disc 30 are performed based on the FTS based on the servo control signal from 6. Further, the optical pickup 22 generates a signal PS based on the light reflected from the mini-disc 30 and supplies the signal PS to the RF amplifier unit 23.

The RF amplifier unit 23 includes an optical pickup 22
, And supplies the read signal RS to the system controller 25 via the signal processing unit 17. Further, based on the signal PS, a focus error signal FE and a tracking error signal TE are generated and supplied to the servo controller 26.

A servo controller 26 is connected to the system controller 25.
Generates a servo control signal VC based on the read signal RS from the optical pickup 22 and supplies the servo control signal VC to the servo control unit 26. The system controller 25 includes an operation unit 28
And a display unit 29 are connected, and a control signal CS is generated according to an operation signal ES from the operation unit 28 to control the operation of the portable electrocardiograph. Further, the system controller 25 generates a display signal ED and supplies it to the display unit 29. The display unit 29 displays information about the operation based on the supplied display signal ED.

The servo control unit 26 has a motor drive signal M for controlling the rotation speed of the spindle motor 21 based on the servo control signal VC from the system controller 25.
D is generated and supplied to the spindle motor 21. The motor drive signal MD is supplied to the spindle motor 21 to rotate the mini disc 30 at a predetermined speed. Further, a focus drive signal FD and a tracking drive signal TD are generated based on the focus error signal FE and the tracking error signal TE from the RF amplifier section 23, and are supplied to the optical pickup 22.

Next, the operation will be described. The sensor signals S1 to S4 obtained by amplifying the action potential generated by the pulsation of the heart by the amplifier unit 12 are low-frequency signals whose frequency band is up to several tens of Hz. Here, when the sensor signals S1 to S4 are sampled to be digital signals, it is necessary to perform sampling at twice or more the frequency of the sensor signal by the sampling theorem. Also, the signal switch 13
Since the sensor signals S1 to S4 of the channels are sequentially selected, the signal switch 13 sequentially selects the sensor signals S1 to S4 of the four channels at (200 × 4) Hz, and the A / D
The conversion unit 14 samples each of the sensor signals S1 to S4 by performing sampling at (200 × 4) Hz.
A sensor data signal Da composed of data obtained by sampling at Hz can be obtained from the A / D converter 14.

The sensor data signal Da obtained in this way is stored in the memory 16 via the memory controller 15. Here, the storage capacity of the memory 16 is 2 Mbit.
And the resolution of the sensor data signal Da is 8 bits,
From equation (1), the memory 16 can store the sensor data signal Da for approximately 5 minutes and 27 seconds.

2Mbit ÷ (200 × 4) Hz ÷ 8bit ≒ 327 seconds (5 minutes 27 seconds) (1)

For this reason, when the sensor data signal Da for 5 minutes is stored in the memory 16, for example, the memory controller 15 reads the sensor data signal Da stored in the memory 16 and records it on the mini disk 30. .

In the mini disk 30, the disk 1
Since the recording capacity per sheet is 140 Mbytes, the sensor data signal Da for 50 hours or more can be recorded on one mini-disc as shown by the equation (2).

140 Mbyte ÷ (200 × 4) Hz ÷ 8bit ≒ 3058 minutes (50 hours 58 minutes) (2)

The resolution of the sensor data signal Da is 8b
For example, when it is set to 16 bits from it, or when the number of signals to be recorded is changed from 4 channels to 8 channels, signals for 25 hours or more, that is, one day can be recorded.

When the recording of the sensor data signal Da is completed, the mini disk 30 on which the sensor data signal Da has been recorded is taken out of the portable electrocardiograph and mounted on the electrocardiogram analyzer. The electrocardiogram analyzer uses a mini disc 30
Is read out, and various analyzes are performed, and the analysis results are displayed on the monitor screen of the electrocardiogram analyzer. It is also output as a hard copy. In addition, assuming that the portable electrocardiograph 10 has a function of reproducing the sensor data signal Da recorded on the mini disc 30, the sensor signals S1 to S4 reproduced by the portable electrocardiograph 10 are analyzed by electrocardiogram analysis. The data may be supplied to an apparatus to perform various types of analysis. In this case, the signal processing section 17 performs error correction processing, EFM demodulation processing, and the like, and the reproduced sensor data signal is sent from the signal processing section 17 to the memory controller 15.
Supplied to This reproduced sensor data signal is stored in the memory 16
Is read out at a predetermined speed, the sensor data signal is separated for each channel, converted to an analog signal, and supplied to the electrocardiogram analyzer as a reproduced sensor signal.

As described above, by converting a sensor signal into a digital signal and recording it using a mini-disc as a recording medium, the S / N is good and the resolution and reliability are not affected by wow and flutter. , It is possible to obtain a reproduction sensor signal having a high level.

Since the sensor data signal is recorded on the mini disk at intervals of, for example, 5 minutes, the driving of the spindle motor and the like is performed intermittently. Here, assuming that the transfer speed at the time of recording the sensor data signal is, for example, 0.3 Mbit / sec (the transfer speed at a mini-disc for recording an audio signal), the sensor data signal of four channels for one day is converted to a resolution of 8
The time required to record in bits is about 31 minutes.

When a sensor data signal is recorded by driving a spindle motor or the like, not only the time required for recording the sensor data signal but also the time required for the minidisk to reach a predetermined rotational speed and the recording end time. Since a brake time for stopping the rotation of the disk is required later, the addition time of the time required to reach the predetermined rotation speed and the brake time is, for example, 50% of the time required for recording. Since the recording time of the sensor data signal is about 31 minutes, the driving time of the spindle motor and the like is about 47 minutes. If the transfer speed at the time of recording the sensor data signal is further increased, the driving time can be further reduced.

As described above, when recording the sensor data signal for one day, the sensor data signal is temporarily stored in the memory, and the data stored in the memory is intermittently recorded on the mini disk. Therefore, the driving time of the spindle motor or the like is short, and one day's worth of sensor data signals can be recorded without using a large-capacity battery or the like, thereby reducing the weight of the portable electrocardiograph. be able to.

Furthermore, since a mini-disc is used as a recording medium, parts of a mini-disc device for recording audio signals can be used, so that a portable electrocardiograph can be constructed at low cost. Further, since the mini disc has a small disc diameter of 64 mm, the size of the portable electrocardiograph can be reduced.

In the above-described embodiment, a mini-disc is used as a recording medium. However, the recording medium is not limited to a mini-disc, but is used in an optical disc capable of recording a signal, for example, a computer device. Of course, a magneto-optical disk or a phase-change optical disk may be used.

[0035]

As described above, according to the present invention, a plurality of channels of analog low-frequency signals detected using a plurality of electrodes are converted to digital data signals, and the data signals are converted to data signals. When a predetermined amount is stored in the storage means, it is recorded on the optical disk. in this way,
Since the signal is converted into a digital data signal and then recorded on the optical disk, the S / N can be improved and the effect of wow and flutter can be prevented. In addition, since recording is performed intermittently, even when analog low-frequency signals of a plurality of channels are recorded for a long time, the recording operation time is short, and the recording is performed for a long time without using a large capacity battery or the like. It can be performed. In addition, the components of the optical disk device for recording an audio signal and a data signal such as a computer device can be diverted, so that the cost can be reduced. Furthermore, if a mini-disc is used as the optical disc, the size of the portable electrocardiograph can be easily reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a portable electrocardiograph 10 according to the present invention.

DESCRIPTION OF SYMBOLS 11-1 to 11-4 Electrode 12 Amplifier section 13 Signal switch 14 A / D conversion section 15 Memory controller 16 Memory 17 Signal processing section 20 Recording head 21 Spindle motor 22 Optical pickup 23 RF amplifier section 25 System Controller 30 mini disk

Claims (2)

[Claims] 1. A portable electrocardiograph in which a plurality of electrodes are attached to a living body, and a low-frequency signal generated by pulsation of the heart is detected and recorded using the plurality of electrodes. Signal conversion means for converting analog low-frequency signals of a plurality of channels detected using the electrodes into digital data signals; data storage means for storing data signals obtained by the signal conversion means; and the data storage Signal recording means for driving the optical disk and recording the data signal stored in the data storage means on the optical disk when the data amount of the data signal stored in the means reaches a predetermined amount. Features a portable electrocardiograph. 2. The portable electrocardiograph according to claim 1, wherein a mini disc is used as said optical disc.