RU2311122C1 - Device for remote control of patients' state - Google Patents

Abstract

FIELD: medicine; diagnostic devices.

SUBSTANCE: device has central station composed of computer, provided with data input and representation devices correspondingly, electromagnet signal receiver, patient's physiological parameters detectors, data conversion unit, electromagnet signal transmitter, electromagnet signal receiver, control unit and autonomous unit for powering all the equipment mounted onto patient (I=1, 2,...K). Any transmitter has master oscillator, phase manipulator, first heterodyne, first mixer, first intermediate frequency mixer, power amplifier. High frequency amplifier, second heterodyne, second mixer, second intermediate frequency mixer, multiplier, band-pass filter and phase detector. Device provides high noise immunity and high degree of truth of data received due to usage of two frequencies and complex signals with phase manipulation.

EFFECT: improved efficiency of operation.

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Description

The proposed device relates to medicine, in particular to diagnostic devices.

Known devices for remote monitoring of the condition of patients (ed. Certificate of the USSR No. 1811380, 1814538; RF patents No. 2048790, 2089094, 2128004, 2181258, 2195168, 2232545, 2236169, 2242920, 2242921; patent WO 89/01312; Tikhomirov V .V. Biotelemetric systems. M: Nauka, 1974, p. 58-78; Frolov MV Control of the functional state of the human operator. M: Nauka, 1987, p. 40-42 and others).

Of the known devices closest to the proposed is a "Device for remote monitoring of patients" (RF patent No. 2048790, AB 5/05, 1991), which is selected as a prototype.

The device contains a transmitter and receiver of electromagnetic signals, a control panel, a sensor of physiological parameters, an information conversion unit. The input of the electromagnetic signal transmitter is connected to the output of the central control panel. An electromagnetic signal receiver with a control unit is located on the patient. Processing of information about the physiological parameters of all observed patients is performed by a computer of the central control panel. The device can significantly simplify and lighten the equipment worn by the patient, observe several patients at the same time and immediately give an alarm in case of deterioration of the condition of the observed patients.

However, the used duplex radio communication is constructed in such a way that all the transmitters and receivers operate at the same carrier frequency. Therefore, the transmitters have a negative effect on their own receivers, reducing their noise immunity and the reliability of the received information.

An object of the invention is to increase the noise immunity and reliability of the received information through the use of two frequencies and complex signals with phase shift keying.

The problem is solved in that the device for remote monitoring of the patient’s condition, consisting in accordance with the closest analogue of the measuring and transmitting unit located on each of the group of simultaneously observed patients, including physiological parameters sensors, information conversion unit, control unit, transmitter and an electromagnetic signal receiver, as well as an autonomous power source, while the outputs of the sensors are connected to the inputs of the information conversion unit, the output of which connected to the input of the transmitter of the electromagnetic signal, the input of the control unit is connected to the output of the receiver, and the output to the input of the information conversion unit, and the central control panel located in the zone of reliable reception of electromagnetic signals, consisting of a computer with input and display devices, the transmitter of the electromagnetic signal, the input of which is connected to the output of the computer, and the receiver of the electromagnetic signal, the output of which is connected to the input of the computer, differs from the closest analogue in that, as an electric complex signals with phase shift keying are used for magnetic signals, each transmitter is made in the form of a serially connected master oscillator, phase shift key, first mixer, the second input of which is connected to the first output of the first local oscillator, the amplifier of the first intermediate frequency and the power amplifier, the output of which is connected to the transmitting antenna, the second input of the phase manipulator of the central control panel is connected to the output of the computer, and the second input of the phase manipulator of the patient is connected to the output of the bl For information conversion, each receiver is made in the form of a high frequency amplifier, a second mixer, the second input of which is connected to the first output of the second local oscillator, of the second intermediate frequency amplifier, multiplier, the second input of which is connected to the second output of the first local oscillator, band pass filter, connected in series to the receiving antenna and a phase detector, the second input of which is connected to the second output of the second local oscillator, while the output of the phase detector of the central control panel is connected to input E VM, and the output of the patient’s phase detector is connected to the input of the control unit, the transmitter of the central control panel emits complex signals with phase shift at frequency W ₁ , and the receiver receives at frequency W ₂ , and the transmitter of each observed patient, on the contrary, emits complex signals with phase shift at a frequency of W ₂ , and the receiver receives at a frequency of W ₁ .

The block diagram of the proposed device is presented in figure 1, the block diagram of the information conversion unit is shown in figure 2, the block diagram of the control unit is shown in figure 3. Timing diagrams explaining the operation of the device are presented in FIGS. 4 and 5. The block diagram of the transmitter and receiver of the central control panel is shown in FIG. 6, and the block diagram of the transmitter and receiver of each observed patient is shown in FIG. 7. A frequency diagram explaining the conversion of signals by frequency is shown in FIG.

A device for monitoring the condition of patients contains a central control panel 1, consisting of a computer 1-1 with devices 1-2 and 1-3 for inputting and displaying information, respectively, an electromagnetic signal receiver 2, an electromagnetic signal transmitter 3 and recorders I, II, i, To the biological parameters located on the patients (i is the number of the patient, which can take values from 1 to K, where K is the total number of patients observed).

The output of the receiver 2, which is a bus of a standard communication interface, is connected to the input of the computer 1-1 of the central control panel 1. The transmitter 3 is also connected by a standard communication interface bus to the computer output 1-1 of the central control panel 1.

The composition of registrars I, II, i. The patients located include sensors (4.i-1) ÷ (4.in) of physiological parameters of the i-th patient (n is the total number, number of sensors installed on the i-th patient), information conversion unit 5.i transmitter 6.i of an electromagnetic signal mounted on the i-th patient, receiver 7.i of the electromagnetic signal on the i-th patient, control unit 8.i of the i-th patient, autonomous power supply 9.i of all equipment installed on i- patient, such as a battery.

The outputs of the sensors (4.i-1) - (4.i-n) are connected to the corresponding inputs of the information conversion unit 5.i, the output of which is connected to the input of the transmitter 6.i. The output of the receiver 7.i is connected to the input of the control unit 8.i, the output of which is connected to the input of the information conversion unit 5.i.

As sensors of physiological parameters, any sensors can be used, for example, ECG meters for patients (electrodes for removing biopotentials with amplifiers), temperature meters, and others. The main function of the conversion unit 5.i is to convert the measured analog signals corresponding to the values of the measured physiological parameters into a serial binary code that can modulate the emitted electromagnetic signal.

The information conversion unit 5.i consists of a switch 10, an analog-to-digital converter (ADC) 11 and an encoder 12. The inputs of the switch 10 are connected to the outputs of the sensors (4.i-1) - (4.in), and the output with the input of the ADC 11 The output of the latter is connected to the input of the encoder 12, the second input of which is connected to the output of the control unit 8.i. Using the switch 10, the sensors (4.i-1) - (4.in) are alternately connected to the input of the ADC 11, which converts the analog information into a parallel binary code, which is then converted using a standard encoder 12 into a serial binary code, for example, in Manchester 2 standard.

The control unit 8.i consists of a decoder 13, two code comparison circuits 14 and 15, two control codes 3U 16 and 17, a time delay unit 18 and an OR circuit 19. The decoder 13 input is connected to the output of the receiver 7.i, and the output the inputs of two schemes 14 and 15 comparison codes, the second inputs of which are connected to the outputs 3U 16 and 17 control codes. The output of the first code comparison circuit 14 is connected through the time delay unit 18 to the first input of the OR circuit 19, and the output of the second code comparison circuit 15 directly with the second input of the OR circuit 19, the output of which is connected to the input of the information conversion unit 5.i.

Each transmitter is made in the form of serially connected master oscillator 20 (33), phase manipulator 21 (34), first mixer 23 (36), the second stroke of which is connected to the first output of the first local oscillator 22 (35), amplifier 24 (37) of the first intermediate frequency and a power amplifier 25 (38), the output of which is connected to a transmitting antenna. In this case, the phase manipulator 21 of the central control panel is connected to the output of the computer 1-1, and the second input of the phase manipulator 34 of each observed patient is connected to the output of the information conversion unit 5.i.

Each receiver is made in the form of a high-frequency amplifier 26 (39), a second mixer 28 (41) connected in series to the output of the receiving antenna, the second input of which is connected to the first output of the second local oscillator 27 (40), the second intermediate frequency amplifier 29 (42), and the multiplier 30 (43), the second input of which is connected to the second output of the first local oscillator, the bandpass filter 31 (44) and the phase detector 32 (45), the second input of which is connected to the second output of the second local oscillator 27 (40). The output of the phase detector 32 of the central control panel is connected to the output of the computer 1-1, and the output of the phase detector 45 of the observed patient is connected to the control unit 8.i.

The main condition for undistorted transmission of information in accordance with the Kotelnikov theorem is:

Fon≥ (3-4) Fmax,

where Fon is the polling frequency (frequency of measurements) of each physiological signal;

Fmax is the maximum value of the frequency of the physiological signal.

It is known that the frequency range of the overwhelming number of physiological signals lies in the range from 0 to 100 Hz. Therefore, the polling frequency (quantization frequency) should be ≈400-500 Hz.

At present, realistically achievable values of the ADC conversion time for such devices can be provided within 20 μs, and the information transfer speed over the radio link is up to 1 Mbit / s. In this case, one 20-bit word can be transmitted in 20 μs.

It can be seen from this that at a selected conversion and transmission rate of information and a polling frequency of 500 Hz, up to 100 physiological parameters can be transmitted simultaneously. If each patient measures and transmits 10 physiological parameters, then in this case, 10 patients can be observed simultaneously. If the number of parameters measured in each patient is reduced to 5, then the number of observed patients can be increased to 20.

The proposed device operates as follows.

Consider as an example two modes of operation of the proposed device:

a) the mode of operation upon request;

b) an operating mode with general synchronization.

Figure 4 shows diagrams illustrating the first mode of operation, figure 5 is a second mode. The abscissa axis on all diagrams shows time. Diagrams A conditionally show the command code messages transmitted via the command line from the central control panel to the equipment of each patient.

For this, the master oscillator 20 generates a harmonic oscillation:

Uc ₁ (t) = Vc ₁ Cos (Wct + φc ₁ ), 0≤t≤Tc ₁ ,

where Vc ₁ , Wc, φc ₁ , Tc ₁ is the amplitude, carrier frequency, initial phase and duration of the oscillation, which is fed to the first input of the phase manipulator 21, to the second input of which a modulating code M ₁ (t) is supplied from the output of the computer 1-1 . As the modulating code M ₁ (t), the code common to all patients or the code of the i-th observed patient can be used. The output of the phase manipulator 21 produces a complex signal with phase shift keying (PSK):

U ₁ (t) = Vc ₁ · Cos [Wct + φк ₁ (t) + φc ₁ ], 0≤t≤Tc ₁ ,

where φк ₁ (t) = {0, π} is the manipulated component of the phase that displays the law of phase manipulation in accordance with the modulating code, and φк ₁ (t) = const at К · τэ <t <(К + 1) · тэ and can change abruptly at t = K · τe, i.e. on the boundaries between elementary premises (K = 1, ..., N)

τe N, is the duration and number of chips that make up a signal of duration Tc ₁ · (Tc ₁ = N · τe), which is fed to the first input of the first mixer 23. The voltage of the first local oscillator 22 is applied to the second input of the last:

Ug ₁ (t) = Vg ₁ · Cos (Wg ₁ t + φg ₁ ).

At the output of the mixer 23, voltages of combination frequencies are generated. The amplifier 24 is allocated the voltage of the first intermediate (total) frequency:

Upr ₁ (t) = Vpr ₁ · Cos [Wpr ₁ t + φк ₁ (t) + φpr ₁ ], 0≤t≤Tc ₁ ,

where Vpr ₁ = K ₁ · Vc ₁ · Vg ₁ ;

K ₁ - gear ratio of the mixer;

Wpr ₁ = Wc + Wg ₁ - the first intermediate (total) frequency (Fig. 8);

φpr ₁ = φс + φг ₁ .

This voltage, after amplification in the power amplifier 25, is radiated by the transmitting antenna on the air at a frequency W ₁ = Wpr ₁ , is captured by the receiving antenna of the i-th patient being monitored, and through the high-frequency amplifier 39 it is supplied to the first input of the mixer 41, to the second input of which voltage Ug ₁ (t) a local oscillator 40. At the output of the mixer 41, voltages of combination frequencies are generated. The amplifier 42 is allocated the voltage of the second intermediate (differential) frequency:

Upr ₂ (t) = Vpr ₂ · Cos [Wpr ₂ t + φк ₁ (t) + φpr ₂ ], 0≤t≤Tc ₁ ,

where Vpr ₂ = 1 / 2K ₁ · Vpr ₁ · Vg ₁

Wpr ₂ = W ₁ -Wg ₁ - the second intermediate (difference) frequency;

φpr ₂ = φpr ₁ -φg ₁ ,

which is fed to the first input of the multiplier 43. The voltage of the local oscillator 35 is supplied to the second input of the multiplier 43:

Ug ₂ (t) = Vg ₂ · Cos (Wg ₂ t + φg ₂ ).

The frequencies Wg ₁ and Wg ₂ local oscillators are spaced by the value of the second intermediate frequency (Fig):

Wg ₂ -Wg ₁ = Wpr ₂ .

The output of the multiplier 43 produces a voltage:

U ₂ (t) ⁼ V ₂ · Cos [Wг ₁ t-φк + φг ₁ ], 0≤t≤Tc ₁ ,

where V ₂ = 1 / 2K ₂ · Vpr ₂ · Vg ₂ ;

K ₂ is the transmission coefficient of the multiplier;

which is allocated by the band-pass filter 44 and fed to the first (information) input of the phase detector 45. The voltage Uг ₁ (t) of the local oscillator 40 is applied to the second (reference) input of the phase detector 45. At the output of the phase detector 45, a low-frequency voltage is generated:

Un ₁ (t) = Vн ₁ · Cosφк ₁ (t),

where Vn ₁ = 1 / 2K ₃ · V ₂ · Vg ₁

To ₃ is the transfer coefficient of the phase detector, proportional to the modulating code M ₁ (t). This voltage is supplied to the control unit 8-i.

Diagrams I, II, i, K show conditionally code messages transmitted via the information line from the equipment located on the patient to the central control panel. Each code parcel indicated in Arabic numerals on the diagrams corresponds to the transmitted value of the measured physiological parameter.

In this case, the harmonic oscillation is also formed by the master oscillator 33:

Uc ₂ (t) = Vc ₂ · Cos (Wct + φс ₂ ), 0≤t≤Тс ₂

which is supplied to the first input of the phase manipulator 34, to the second input of which a modulating code M ₂ (t) is supplied from the output of the information conversion unit 5.i. As the modulating code M ₂ (t), a code package is used that corresponds to the value of the measured physiological parameter of the i-th observed patient.

The output of the phase manipulator 34 produces a complex signal with phase shift keying (PSK):

U ₃ (t) = Vc ₂ · Cos [Wct + φк ₂ (t) + φc ₂ ], 0≤t≤Tc ₂ ,

which is supplied to the first input of the mixer 36, to the second input of which a voltage Ug ₂ (t) of the local oscillator 35 is supplied.

At the output of the mixer 36, voltages of combination frequencies are generated. Amplifier 37 is allocated voltage intermediate (differential) frequency:

Upr (t) = Vpr · Cos [Wprt-φk ₂ (t) + φpr], 0≤t≤Ts _2,

where Vpr = 1 / 2K ₁ · Vc ₂ · Vg ₂ ;

Wpr = Wg ₂ -Wc - intermediate (difference) frequency;

φpr = φc-φg ₂ .

This voltage after amplification in the power amplifier 38 is radiated by the transmitting antenna on the air at a frequency of W ₂ = Wpr, is picked up by the receiving antenna of the central console and through the high-frequency amplifier 26 is supplied to the first input of the mixer 28, the second input of which is the voltage Ug ₂ (t} of the local oscillator 27. The voltage of the combination frequencies is formed at the output of the mixer 28. The voltage of the second intermediate (difference) frequency is allocated by the amplifier 29:

Upr ₃ (t) = Vpr ₃ · Cos [Wpr ₂ t + φк ₂ (t) + φpr-3], 0≤t≤Ts ₂ ,

where Vpr ₃ = 1 / 2K ₁ · Vpr · Vg ₂ ;

Wpr ₂ = Wg ₂ -Wpr - the second intermediate (difference) frequency;

φpr ₃ = φg ₂ -φpr,

which is fed to the first input of the multiplier 30, to the second input of which the voltage Ug ₁ (t) of the local oscillator 22 is supplied. The voltage is generated at the output of the multiplier 30:

U ₄ (t) = V ₄ · Cos [Wг ₂ t + φк ₂ (t) + φг ₂ ], 0≤t≤Тс ₂ ,

where V ₄ = 1 / 2K ₂ · Vpr ₃ · Vg ₁ ;

Wg ₂ = Wpr ₂ + Wg ₁ ;

φg ₂ = φpr ₃ + φg ₁ ,

which is allocated by a band-pass filter 31 and fed to the first (information) input of the phase detector 32.

At the second (reference) input of the phase detector 32, a voltage Ug ₂ (t) of the local oscillator 27 is applied. At the output of the phase detector 32, a low-frequency voltage is generated:

Un ₂ (t) = Vн ₂ · Cosφк ₂ (t),

where Vn ₂ = 1 / 2K _{3 ·} V ₄ · Vg ₂ ;

proportional to the modulating code M ₂ (t). This voltage is fed to the input of the computer 1-1.

When the mode of operation on demand (figure 4), all command code parcels have different meanings: each patient is assigned a code. The program for interrogating sensors measuring physiological parameters in the patient’s equipment is launched after the command code is accepted and decrypted (in diagrams this moment of time is indicated by shaded rectangles). The frequency of the survey of each patient is 400-500 Hz, which corresponds to a complete cycle of the survey of all patients 2-2.5 ms. The advantage of this mode of operation is its flexibility: if you wish, you can interview not all patients, but part of them or even one patient, but with a higher frequency.

In the case of applying the operating mode with general synchronization, the equipment of all patients is configured to one common code, according to which the software devices of the equipment of all patients are simultaneously launched (Fig. 5). These time-programmed devices are configured in such a way that each subscriber is connected to the communication line at a certain point in time after receiving the synchronization code, therefore, the time intervals of the transmission of information by the subscribers to the central point are separated in time. The advantage of this mode of operation is a shorter information transfer cycle and higher noise immunity. Its disadvantages include significantly less flexibility: in this case, it is impossible to change the program for connecting subscribers from the central console.

However, the above proposed circuit of the control unit 8.i (Fig. 3) allows to implement both modes of operation of the device. This is done as follows. In memory 17, each patient has their own code. In the memory 16 is entered one common code for all patients.

When working on request from the central control panel, a code corresponding to the code recorded in memory 17 is supplied. According to this code, the equipment of only one selected patient is turned on, all its physiological parameters are measured in accordance with the program, and the measurement result in a short period of time after sending the control The code is transmitted over the information line to the central control panel.

Then, the code of another patient is sent from the central control panel and the whole procedure is repeated. So alternately (with a frequency of 500 Hz) all observed patients are interrogated.

This system allows, if necessary, to change the survey program, for example, to interview with a higher frequency a limited number of patients or even one patient. Such a need may arise, for example, in the transmission of myographic information or in the analysis of evoked ECG potentials, where a higher sampling rate is required.

In the case of applying the operation mode with general synchronization from the central console, a code corresponding to the code recorded in the memory 16, common to all subscribers, is supplied via the command line. According to this code, each patient’s equipment is turned on at a time determined by the delay time block 18, which is set individually for each patient so that the moments of interrogation and transmission of information of all patients to the central console are separated in time.

Formed as a result of the interrogation of the code parcels 1, 2, n shown in the diagrams (Fig. 4), the electromagnetic signal emitted by the transmitters 6 is modulated (Fig. 1). Information on the physiological parameters of all patients, adopted by the receiver 2, is entered into the computer 1-1 of the central console 1.

Next, mathematical express processing is performed in real time of all physiological parameters of the observed patients, and if they deviate beyond the permissible limit for a patient, the computer generates an alarm signaling the patient number for emergency measures.

In addition, the received information can be stored in the memory of a computer for subsequent more detailed analysis.

Compared with known monitors, including monitors that record information on magnetic tape, this device allows you to expand the functionality of:

- observe in real time several patients at once and immediately give an alarm in the event of a worsening of the condition of the patients;

- make the subsequent more detailed analysis of the information received;

- significantly simplify, reduce the cost and lighten the equipment worn by the patient, due to the fact that the complex computer or tape recorder is excluded from the composition of the equipment, and all information processing is performed in the computer of the central control panel.

Thus, the proposed device in comparison with the prototype provides increased noise immunity and reliability of the exchange of discrete information between the central control panel and the observed patients. This is achieved by using two frequencies W ₁ , W ₂ and complex PSK signals.

From the point of view of detection, these signals have high energy and structural secrecy.

The energy secrecy of the FMN signals is due to their high compressibility in time and spectrum with optimal processing, which reduces the instantaneous radiated power. As a result, a complex QPSK signal at the receiving point may be masked by noise and interference. Moreover, the energy of a complex QPSK signal is by no means small; it is simply evenly distributed over the time-frequency domain so that at each point in this region the signal power is less than the power of noise and interference.

The structural secrecy of complex QPSK signals is due to the wide variety of their forms and significant ranges of parameter changes, which makes it difficult to optimize or at least quasi-optimal processing of complex QPSK signals of an a priori unknown structure in order to increase the sensitivity of receivers.

Complex QPSK signals open up new possibilities in the technique of transmitting discrete messages and protecting them from unauthorized access. These signals allow the use of a new type of selection - structural selection. This means that it becomes possible to distinguish complex QPSK signals from other signals and interference operating in the same frequency band and at the same / time intervals. This feature is realized by convolution of the spectrum of complex PSK signals.

Claims (1)

A device for remote monitoring of the patient’s condition, consisting of a measuring and transmitting unit located on each of a group of simultaneously observed patients, including physiological parameters sensors, an information conversion unit, a control unit, an electromagnetic signal transmitter and receiver, as well as an autonomous power source, the outputs of the sensors are connected to the inputs of the information conversion unit, the output of which is connected to the input of the transmitter of the electromagnetic signal, the input of the control unit The line is connected to the output of the receiver, and the output to the input of the information conversion unit, and the central control panel located in the zone of reliable reception of electromagnetic signals, consisting of a computer with input and display devices, an electromagnetic signal transmitter, the input of which is connected to the computer output, and the receiver electromagnetic signal, the output of which is connected to the input of the computer, characterized in that each transmitter of the electromagnetic signal is made in the form of series-connected master oscillator, f a basic manipulator, a first mixer, the second input of which is connected to the first output of the first local oscillator, an amplifier of the first intermediate frequency and a power amplifier, the output of which is connected to a transmitting antenna, while the second input of the phase manipulator of the central control panel is the input of the transmitter of the central panel, and the second input is the phase the patient’s manipulator is the input of the patient’s transmitter, each electromagnetic signal receiver is made in the form of amplified in series with the receiving antenna For high frequency, a second mixer, the second input of which is connected to the first output of the second local oscillator, an amplifier of the second intermediate frequency, a multiplier, the second input of which is connected to the second output of the first local oscillator, a bandpass filter, and a phase detector, the second input of which is connected to the second output of the second local oscillator, the output of the phase detector of the central control panel is the output of the receiver of the central console, and the output of the phase detector of the patient is the output of the patient receiver, the transmitter is cent The remote control unit is capable of emitting complex signals with phase shift keying at frequency W ₁ , and the receiver is capable of receiving signals at frequency W ₂ , and the transmitter of each observed patient is capable of emitting complex signals with phase shift keying at frequency W ₂ , and the receiver - with the ability to receive signals at a frequency of W ₁ .

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