JPH0336329Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a medical telemeter device when used as a telemeter device.

[Summary of the idea]

This device demodulates a plurality of mixed subcarriers from a received high-frequency signal, and separates and demodulates the subcarriers to obtain at least one biological signal and at least one status signal. and a plurality of detection means for respectively detecting the levels of subcarriers of the status signal, a gate means for opening and closing the gate according to the outputs of the plurality of detection means, and outputting the biological signal and the signal other than the biological signal as a gate signal. A highly accurate telemeter system that can prevent interference caused by interference by having a switching means that switches according to It was designed to construct a .

[Prior Art] Generally, when an FM telemeter device receives strong interference, the radio waves with the stronger electric field strength may be overpowered, resulting in so-called data substitution. Particularly in the case of medical use, misdiagnosis may endanger human life, and it is necessary to consider some countermeasures as soon as possible.

There are two main methods for preventing interference used in such telemeter devices: a carrier sense method and a method for monitoring electric field strength. The carrier sense method is currently used in cordless telephones and the like. Normally, the most reliable way to prevent interference is not to emit radio waves at the same frequency, but this carrier sensing method uses a receiver to monitor whether or not radio waves have already been emitted. For example, the structure is such that they do not emit radio waves at the same frequency. Also, the method of monitoring the electric field strength is to monitor the electric field strength level of the receiver, and to not use signals below a certain level limit as data.

[Problems to be solved by the invention] However, in the case of the above-mentioned carrier sensing method, first, a receiver for carrier sensing is required on the transmitter side, so there are limitations on power consumption, size, and weight. Additionally, it has drawbacks such as being unsuitable for wireless microphones and medical telemeter devices, which perform unidirectional communication and are often used for long periods of time once they are put into operation.
Furthermore, in the case of a method of monitoring electric field strength, it is usually widely used because there is no other effective method, but it has drawbacks such as being affected by interference.

This idea was created in view of this point, and it eliminates the above-mentioned drawbacks and provides highly safe transmission that makes it possible to detect when signal substitution occurs due to interference from external radio waves. The present invention provides a telemeter device that can ensure the following.

[Means for solving the problem] This invention demodulates a plurality of mixed subcarriers from a received high frequency signal, separates and demodulates these subcarriers, and obtains at least one biological signal and at least one status signal. In the telemeter device, a plurality of detection means (12 to 15) each detecting the level of subcarriers of the separated biological signal and status signal;
The gate means 16 opens and closes the gate according to the outputs of the plurality of detection means, and the switching means 17 switches between a biological signal and a signal other than the biological signal according to the output of the gate signal. The device is configured to determine the model generating the biosignal and status signal based on the output.

[Operation] The signal from the high frequency circuit 2 is demodulated by the demodulation circuit 3 to obtain a plurality of mixed subcarriers. These subcarriers are separated through filters (4 to 7) and demodulated by subcarrier demodulation circuits (8 to 11) to obtain at least one biological signal such as an electrocardiogram signal and at least one status signal such as a low battery signal, a nurse signal, etc. Get call signal or electrode abnormal signal. Then, each of the separated subcarriers is connected to a subcarrier level detection circuit (12 to 1
5) and compares it with a reference value, and if it is larger than this, a high level signal is output. The high level signal is supplied to an AND circuit 16 serving as gate means, the gate of which is opened and a detection signal is generated. In other words, it is determined from this detection signal that the model that is generating the biological signal and the status signal is the true model that is attempting to receive the signal, and that it is not receiving the interference signal. This makes it possible to prevent signal substitution due to interference between systems made by other companies of the same model or for different purposes, and it is possible to construct a highly accurate telemeter system.

[Example] Hereinafter, an example of this invention will be described in detail based on FIGS. 1 to 4.

Figure 1 shows the configuration of the first embodiment of this invention.Currently, the biological information monitored by medical telemeter devices includes electrocardiogram, electroencephalogram, GSR, electromyogram, respiration curve, body temperature, blood pressure, etc. However, here, we will explain the case of an electrocardiogram as a representative example.

In Figure 1, 1 is a receiving antenna, 2 is a high frequency circuit, 3 is a demodulation circuit, 4 is a filter that extracts, for example, a 1kHz subcarrier assigned to an electrocardiogram signal as a biological signal, and 5 to 7 are also used as status signals. For example, the signals assigned to the battery low signal, nurse call signal, and electrode abnormality signal are respectively assigned to
A filter that extracts subcarriers of 300Hz, 500Hz, and 800Hz; 8 is a subcarrier demodulation circuit that demodulates the subcarriers from filter 4 to obtain an electrocardiographic signal;
9 to 11 demodulate the subcarriers from filters 5 to 7, respectively, to generate a low battery signal, a nurse call signal,
This is a subcarrier demodulation circuit that obtains an electrode abnormality signal. Note that each frequency of the subcarrier is determined for each manufacturer when designing a model, and it is very unlikely that the frequency will be the same between systems of different manufacturers and models.

12 to 15 are subcarrier level detection circuits for detecting the presence or absence of subcarriers from the filters 4 to 7, respectively, and each has a reference value, and when the carrier level is lower than this reference value, it outputs a low level signal indicating that there is no carrier. When the carrier level is higher than the reference value, a high level signal indicating that there is a carrier is generated. 10 is an AND circuit as gate means, and subcarrier level detection circuits 12 to 1
When a high level signal that all carriers have is supplied from 5, the gate is opened and a detection signal indicating that a specific radio wave has been received, that is, an electrocardiogram signal and a status signal of the assigned subcarriers as described above are generated. It generates a detection signal that can be used to identify the type of device that is running.

Next, the operation of the circuit shown in FIG. 1 will be explained. antenna 1
The radio waves received are amplified by a high frequency circuit 2, demodulated by a demodulation circuit 3, and the mixed subcarriers are obtained on the output side. Each of these subcarriers is extracted by filters 4 to 7, and demodulated by subcarrier demodulation circuits 8 to 11. An electrocardiographic signal is obtained on the output side of demodulation circuit 8, and this electrocardiographic signal is sent to a measuring section (not shown). is supplied to the computer, measured, and then displayed or recorded.

Further, a low battery signal is obtained on the output side of the demodulation circuit 9, and is supplied to the measuring section to generate an alarm on the receiving side, and the battery of the transmitter attached to the patient or the like is replaced. Further, a nurse call signal is obtained at the output side of the demodulation circuit 10, and is supplied to the measuring section, whereby an alarm is generated and a call to the nurse is transmitted. In addition, an electrode abnormality signal is obtained on the output side of the demodulation circuit 11, and is supplied to the measurement unit, which indicates that the electrode attached to the patient etc. has come off, or that the jelly has dried up and the resistance has increased, etc. An abnormality in the electrode is generated as an alarm on the receiving side.

In addition, subcarrier level detection circuits 12 to 15
The presence or absence of each subcarrier is detected at
When all subcarriers are detected, AND circuit 16
The gate is opened and a high-level detection signal is obtained, which is then supplied to the CPU of the measurement unit. This determines that the device is receiving a specific radio wave and is in a normal state. Further, if a subcarrier is not detected at even one location in the detection circuits 12 to 15, the gate of the AND circuit 10 is closed and a low level detection signal is obtained, which is supplied to the CPU of the measurement section.

When this low level detection signal is supplied,
In other words, when substantially no detection signal is detected, interference is occurring, so the electrocardiographic signal may be masked using software, or may be switched to a unique signal that does not cause misdiagnosis using hardware.

FIG. 2 shows a case where the electrocardiographic signal is masked by hardware when the carrier level in the high frequency circuit 2 is normal, interference occurs, and substantially no detection signal is output to the output side of the AND circuit 16. That is, the analog switch 17 is connected to the demodulation circuit 8 and the AND circuit 16.
When the detection signal is at a high level, the switch 17 is connected to the contact a side to supply the electrocardiographic signal from the demodulation circuit 8 to the measurement section, and when the detection signal is at a low level, the switch 17 is connected to the contact a side. By switching to the contact b side, a triangular wave of 20 Hz, for example, is supplied to the measurement unit as a unique signal that does not cause misdiagnosis.

In this way, in this embodiment, the presence or absence of a plurality of subcarriers each having a preset frequency according to the model is detected, and when all subcarriers are detected, a detection signal is essentially output, so that interference caused by external radio waves, etc. Even if signal substitution occurs, this can be detected and highly secure transmission can be ensured.

Figure 3 shows a second embodiment of this invention.
In this figure, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In this embodiment, since the data signals other than the biological signals are binary low-speed signals, they are treated as serial digital signals. That is, status signals such as a low battery signal, a nurse call signal, an electrode abnormality signal, etc. are combined and treated as a serial digital signal. For this purpose, a subcarrier of, for example, 200 Hz is assigned to this serial digital signal and extracted by the filter 20.

The subcarrier extracted by the filter 20 is demodulated by a subcarrier demodulation circuit 21, and a data string as shown in FIG. 4 is demodulated. This demodulation circuit 21
The conditions for data stream demodulation are that the synchronization pulse is high for 2 time slots for T ₁ hour, and after T ₁ hour 1
Set to low level (blank) for the time slot, and set the synchronization pulse interval time to _T2 .

The data string demodulated in this manner is supplied to a data string digital demodulation circuit 24, where the serial signal is converted into a parallel signal, and the signals are taken out as a low battery signal, a nurse call signal, and an electrode abnormality signal, respectively.

Further, the synchronization state in the data string digital demodulation circuit 24 is detected by the synchronization detection circuit 23, and the detection signal (synchronization detection flag) is supplied to the AND circuit 16. Therefore, in the AND circuit 16, when a subcarrier is detected by the subcarrier detection circuits 12 and 22 and a synchronization signal is detected by the synchronization detection circuit 23, the gate is opened and a detection signal indicating that a specific radio wave has been received, that is, the above-mentioned A detection signal is generated to determine that the electrocardiographic signal and status signal of the assigned subcarrier are being generated.

In this way, this embodiment can have almost the same effect as the above embodiment, and furthermore, in this embodiment, the data structure is the same as that of other companies' models, and there is a very low probability that the synchronization detection flag will be set. Therefore, a detection signal with higher accuracy than that in the first embodiment can be obtained.

[Effects of the invention] As described above, according to this invention, the presence or absence of subcarriers related to biological signals and status signals is detected and supplied to the gate means, and the biological signals and status signals are generated by the output of the gate means. Since a detection signal is obtained that can determine the type of model present, various interferences such as signal substitution due to interference can be prevented, and a highly accurate telemeter system can be constructed.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram showing one embodiment of this invention, FIG. 2 is a configuration diagram showing a part of the main part of this invention, and FIG. 3 is a circuit diagram showing another embodiment of this invention. FIG. 4 is a diagram showing the data string structure according to this invention. 2 is a high frequency circuit, 3 is a demodulation circuit, 4 to 7 are filters, 8 to 11, 21 are subcarrier demodulation circuits,
12 to 15, 22 are subcarrier level detection circuits, 16 is an AND circuit, 23 is a synchronization detection circuit, 2
4 is a data string digital demodulation circuit.

Claims (1)

[Claims for Utility Model Registration] 1. A telemeter device that demodulates a plurality of mixed subcarriers from a received high-frequency signal, and separates and demodulates the subcarriers to obtain at least one biological signal and at least one status signal. , a plurality of detection means for detecting the levels of subcarriers of the separated biological signal and status signal, respectively; gate means for opening and closing a gate in accordance with the outputs of the plurality of detection means; the biological signal; and the biological signal. A telemeter comprising a switching means for switching between signals other than the above according to the output of the gate means, and a model generating the biological signal and the status signal is determined based on the output of the gate means. Device. 2. The status signal comprises a serial digital signal representing a plurality of status signals.
Telemeter device as described.