JP2001320285A - Data transmitter, nurse call transmitter and nurse call system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the miniaturization of a configuration of a data transmitter while canceling trouble in the control of an oscillation frequency of the data transmitter. SOLUTION: A serial circuit composed of a capacitor 1 and a diode 2 is parallel connected to the parallel circuit of a capacitor 102g and a variable capacitor 102h in a Clapp oscillation circuit 102 and a data signal outputted as a binary signal from an output terminal A of a control circuit 101 is inputted through a resistor 3 to the contact of the capacitor 1 and the diode 2. When the data signal is '1', the diode 2 is turned on and the capacitor 1 is connected to the oscillation circuit 102. When the data signal is '0', the diode 2 is turned off and the capacitor 1 is disconnected from the oscillation circuit 102. Hence, the deviation quantity of the oscillation frequency corresponds to the capacity value of the capacitor 1 and the adjustment of the deviation quantity is unnecessitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a data transmission device, a nurse call transmitter, and a nurse call system.

2. Description of the Related Art Conventionally, a data transmission device used for a wireless nurse call transmitter, for example, outputs transmission data represented by a binary signal from an output terminal A of a control circuit 101 as shown in FIG. Oscillation circuit 10 according to signal
2, the frequency of the transmission signal is modulated. Hereinafter, FIG. 4 will be briefly described. Oscillation circuit 10
A so-called clap oscillation circuit 2 uses a SAW resonator 102a as an inductance component and a transistor 1
02b, capacitors 102c to 102g, variable capacitance capacitor 102h, resistors 102i, 102j, 102k, and the like. A voltage variable capacitance element 103 such as a variable capacitance diode whose capacitance value changes according to an applied voltage is connected in parallel to a capacitor 102 g in the oscillation circuit 102, and the oscillation circuit 102 determines the capacitance value of the voltage variable capacitance element 103. The oscillation frequency changes according to the size. The applied voltage of the voltage variable capacitance element 103 is switched by an applied voltage switching circuit 104 according to a data signal composed of a binary signal “1” and “0” output from an output terminal A of the control circuit 101. Hereinafter, the switching operation of the applied voltage and the frequency adjustment operation accompanying the switching operation will be briefly described. When the control circuit 101 outputs "1" from the output terminal A, the transistor 104a is turned off, the transistor 104b is turned on, the terminal B is at the ground level, and almost no voltage is applied to the voltage variable capacitance element 103, and the voltage is changed. The capacitance value of the capacitor 103 is determined. At this time, if the oscillation frequency of the oscillation circuit 102 does not reach a predetermined value due to the variation (individual difference) of the voltage variable capacitor 103, that is, the variation of the voltage-capacitance value characteristic of the voltage variable capacitor 103, the variable capacitor 102h Is adjusted to set the oscillation frequency to a predetermined value. When the control circuit 101 outputs "0" from the output terminal A, the transistor 104a is turned on, the transistor 104b is turned off, and the voltage at the terminal B is obtained by dividing the output voltage of the constant voltage circuit 105 by the variable resistor 104c and the resistor 104d. The voltage according to this voltage value is applied to the voltage variable capacitance element 103. At this time, if the oscillation frequency of the oscillation circuit 102 does not reach a predetermined value due to the variation (individual difference) of the voltage variable capacitance element 103, that is, the variation of the voltage-capacitance value characteristic of the voltage variable capacitance element 103, another viewpoint is considered. If the deviation amount with respect to the oscillation frequency when the output terminal A of the control circuit 101 is "1" is not a predetermined value, the variable resistor 104c is adjusted to change the voltage applied to the voltage variable capacitance element 103. The oscillation frequency of the oscillation circuit 102 is set to a predetermined value. FIG.
, 104e to 104i are resistors. The antenna 106 is an oscillation circuit 1 input via a capacitor 107.
02 is wirelessly transmitted. Reference numeral 108 denotes a power supply (battery).

In the above-described apparatus, the adjustment (individual difference) of the voltage variable capacitance element 103, that is, the adjustment caused by the voltage-capacitance value characteristic variation of the voltage variable capacitance element 103 is performed for each oscillation frequency. I had to. In other words, in addition to the adjustment of the reference frequency, it is necessary to adjust the frequency shift amount. Furthermore, since the voltage-capacitance value characteristic of a voltage variable capacitance element is generally nonlinear,
Adjusting the oscillation frequency to a desired value by adjusting the voltage applied to the voltage variable capacitance element due to the variation in the non-linear portion was a very troublesome operation. In addition, a plurality of types of circuits and elements for the adjustment are required, and the configuration is complicated. In addition, a constant voltage circuit or the like that stabilizes the applied voltage of the variable capacitance element is required to make the modulation degree constant,
There is a problem that the number of parts increases and the configuration becomes complicated. In addition, since the change in capacitance of the variable capacitance element is generally small in the low voltage range of the applied voltage, the applied voltage of the variable capacitance element needs to be higher than the power supply voltage in order to obtain a certain degree of modulation. In some cases, a booster circuit was required. An object of the present invention is to provide a frequency modulation circuit for data communication, a nurse call transmitter, and a nurse call system that can reduce a troublesome adjustment operation and simplify the configuration.

According to the present invention, there is provided an oscillation circuit whose oscillation frequency changes according to the magnitude of a capacitance component connected as a circuit, a data signal generator for outputting a data signal composed of a binary signal, A switching element that is turned on / off according to a signal, a capacitance component whose connection as a circuit to the oscillation circuit is controlled according to the on / off of the switching element, and a transmission unit that transmits a signal according to the oscillation frequency of the oscillation circuit. including. Therefore, it is not necessary to perform cumbersome adjustment for each oscillation frequency due to the voltage variable capacitance element variation (individual difference), that is, the variation of the voltage-capacitance value characteristic of the voltage variable capacitance element, and it is not necessary to adjust the frequency shift amount. In addition, the frequency adjustment can be simplified. In addition, a plurality of adjustment circuits and elements are not required, and the configuration can be simplified. The present invention provides a nurse call operation unit, an oscillation circuit that starts operation in accordance with the operation of the nurse call operation unit and an oscillation circuit whose oscillation frequency changes according to the size of a capacitance component connected as a circuit, and the nurse call operation unit. 2 according to a preset identification code when operated
An identification data signal generator that outputs a data signal composed of a value signal, a diode that is turned on and off in accordance with the data signal, and a capacitance component whose connection as a circuit to the oscillation circuit is controlled in accordance with on and off of the diode. And a nurse call signal transmitting unit for transmitting a signal corresponding to the oscillation frequency of the oscillation circuit. Therefore, in the nurse call transmitter, the voltage variable capacitance element variation (individual difference),
That is, it is not necessary to perform a troublesome adjustment due to the variation in the voltage-capacitance value characteristics of the voltage variable capacitance element for each oscillation frequency, so that it is not necessary to adjust the frequency shift amount, and the frequency adjustment can be simplified. Further, a plurality of types of adjustment circuits and elements are not required, and the configuration can be simplified. The present invention provides the nurse call transmitter, a receiving unit that receives a signal transmitted from the nurse call transmitter, and a display corresponding to the determined identification code while determining the identification code from the received signal and Since the system includes a nurse call management unit for giving a warning, the frequency adjustment and the configuration of the nurse call system can be simplified, and the system can be easily handled.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to an embodiment shown in the drawings. In FIG. 1, a nurse call transmitter 10a to 10z as a data transmission device is carried, for example, by a patient or the like, and when a nurse call switch 4 as a nurse call operation unit is operated, a different data signal is generated for each nurse call transmitter. Identification code ("I
A nurse call signal including “Da” to “IDz”) is transmitted. The receiving units 20a to 20n are installed in, for example, hospital rooms and corridors, and receive nurse call signals transmitted from the nurse call transmitters 10a to 10z. The display device 30 as a nurse call management unit determines an identification code preset for each nurse call transmitter based on the nurse call signal received by the receivers 20a to 20n, and displays a display according to the determination result on the display unit. The warning is performed at 30a or the speaker 30b. FIG. 2 shows details of the nurse call transmitters 10a to 10z shown in FIG.
Since the nurse call transmitters 10a to 10z have the same configuration, only the nurse call transmitter 10a is shown in FIG. In FIG. 2, one end of a capacitor 1 as a capacitance component is connected to the capacitor 1 in the oscillation circuit 102.
02g and a variable capacitor 102h are connected to one end of a parallel circuit, and the other end is connected to the output terminal A of the control circuit 101 via the anode of the diode 2 as a switching element and the resistor 3. The cathode of the diode 2 is connected to the other end of the parallel circuit of the capacitor 102g and the variable capacitor 102h in the oscillation circuit 102. That is, the series circuit of the capacitor 1 and the diode 2 is connected in parallel with the parallel circuit of the capacitor 102g and the variable capacitor 102h in the oscillation circuit 102,
A nurse call signal including a data signal is supplied from the control circuit 101 to the contact between the capacitor 1 and the diode 2 via the resistor 3. Control circuit 10 as data signal generator
1 is a CPU 101a, a ROM 101b, a RAM 101
c, etc., and controls various operations. ROM 101b
Stores an identification code (“IDa” in this example) in advance. In the figure, the same components as those in FIGS. 1 and 4 are denoted by the same reference numerals. Next, the operation will be described. When the voltage of the battery 108 is supplied in accordance with the operation of the nurse call switch 4 by the user, the control circuit 101 starts operating and a nurse call including a data signal corresponding to the identification code “IDa” stored in the ROM 101b in advance. The signal is output from the output terminal A as a binary signal. When "1" is output from the output terminal A of the control circuit 101, the diode 2 is turned on, and the capacitor 1 is connected to the oscillation circuit 102.
Capacitor 102g and variable capacitor 10
2h is connected in parallel. That is, the capacitor 1 is connected to the oscillation circuit 102 as a circuit. Therefore, the oscillation circuit 10
Numeral 2 oscillates at an oscillation frequency in which the capacitance value of the capacitor 1 is a part of the determinant of the oscillation frequency. When “0” is output from the output terminal A of the control circuit 101, the diode 2 is turned off, and the capacitor 1 is cut off from the oscillation circuit 102 in circuit. That is, the capacitor 1 is
Deviates from the determinant of the oscillation frequency. Therefore, the oscillation circuit 102 oscillates at an oscillation frequency not related to the capacitance value of the capacitor 1. FIG. 3 shows a nurse call signal output from the output terminal A of the control circuit 101 and the oscillation circuit 1.
2 is an example showing a relationship with an oscillation frequency of 02. In addition,
In this example, the oscillation frequency when the data of the nurse call signal is "1" is set to be lower than the oscillation frequency when the data signal is "0", but this relationship may be reversed. Good. As described above, the on / off of the diode 2 is controlled depending on whether the data of the nurse call signal output from the output terminal A of the control circuit 101 is “0” or “1”. The connection to the oscillator 102 is controlled and the oscillation circuit 10
Since the oscillation frequency of No. 2 changes, an FM modulated wave corresponding to a nurse call signal output from the control circuit 101 is transmitted from the antenna 106 as a transmission unit. Generally, the variation (individual difference) in the capacitance value of the capacitor is extremely small as compared with the variable capacitance diode, and thus the amount of deviation of the oscillation frequency is determined by the capacitance value of the capacitor 1. Therefore, it is not necessary to adjust the frequency shift amount. Incidentally, the oscillation frequency is adjusted, for example, when the data is “1” or “0”.
In any of the cases, the variable capacitor 102h
Or the square wave is output from the output terminal A of the control circuit 101, and the value of the variable capacitor 102h may be adjusted while observing the frequency spectrum of the oscillation waveform at this time. In other words, since the frequency shift amount is stable,
Adjustment of the oscillation frequency is sufficient only by adjusting one of the plurality of oscillation frequencies. That is, only one operation is required. In addition, only one frequency adjustment element or circuit is required, and the configuration can be simplified. Further, since a voltage variable capacitance element is not used, a constant voltage circuit for stabilizing the applied voltage of the voltage variable capacitance element or a method for changing the capacitance value of the voltage variable capacitance element by a predetermined value may be required. The booster circuit can be omitted, and the configuration can be simplified. In the above, an example was shown in which the data communication device was adopted as a nurse call transmitter,
The present invention is not limited to this, and can be applied to various data transmission devices. When a data transmission device is used in a nurse call transmitter, a nurse call transmitter that can be downsized and cost-effective and that can easily adjust the frequency can be provided. In the system, an easy-to-use nurse call system can be provided by downsizing and cost reduction of the configuration. In the above description, the SAW resonator is used as the oscillation inductance component of the oscillation circuit. However, the inductance component is not limited to this, and can be appropriately changed. In the above description, the clap oscillation circuit is used as the oscillation circuit. However, the oscillation circuit is not limited to this, and may be any circuit that includes a capacitance value as an oscillation frequency determining element. Although a diode is used as the switching element in the above description, the switching element is not limited to this and can be changed as appropriate.

According to the present invention, there is provided a transmitter for transmitting a signal corresponding to an oscillation frequency of the oscillation circuit and a capacitance component whose connection to an oscillation circuit is controlled in accordance with the on / off of a switching element which is turned on / off in response to a data signal. Therefore, the necessity of using a voltage variable capacitance element conventionally used for frequency modulation can be eliminated. In addition, it is not necessary to perform cumbersome adjustments for each oscillation frequency due to variations in the voltage variable capacitance element (individual differences), that is, variations in the voltage-capacitance value characteristics of the voltage variable capacitance element, and it becomes unnecessary to adjust the frequency shift amount. ,
Frequency adjustment can be simplified. In addition, a plurality of adjustment circuits and elements are not required, and the configuration can be simplified. Further, according to the present invention, in a nurse call transmitter or a nurse call system, the necessity of using a voltage variable capacitance element used for frequency modulation can be eliminated, and troublesome adjustment does not need to be performed for each oscillation frequency. Adjustment of the shift amount can be made unnecessary, the adjustment operation can be simplified, and the configuration of the adjustment circuit and element can be simplified.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a circuit diagram showing one embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a relationship between a data signal (nurse call signal) and an oscillation waveform.

FIG. 4 is a circuit diagram showing a conventional data transmission device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Capacitance component 2 Switching element 4 Nurse call operation part 10 Nurse call transmitter 20 Reception part 30 Nurse call management part 101 Data signal generation part 102 Oscillation circuit 106 Transmission part (antenna)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04M 9/00 H04M 9/00 FF Term (Reference) 4C341 LL10 5J079 AA06 BA11 BA44 DA12 DA13 FA02 FA13 FA14 FA15 FA21 GA02 KA05 5J081 AA03 BB01 BB09 CC22 CC25 DD02 DD26 EE02 EE03 EE13 FF11 FF25 KK02 KK07 KK23 LL01 MM01 5K038 AA02 BB01 DD12 DD16 FF01 5K060 CC04 DD09 HH01 HH23 JJ02 JJ04 JJ06 JJ06 JJ08 JJ08 JJ08 JJ06 JJ06 JJ06 JJ08

Claims (3)

[Claims] 1. An oscillation circuit connected to a circuit, the oscillation frequency of which changes according to the magnitude of a capacitance component, a data signal generator for outputting a data signal composed of a binary signal, and a switching element that is turned on / off in response to the data signal. And a transmission component that transmits a signal corresponding to the oscillation frequency of the oscillation circuit, and a capacitance component whose connection as a circuit to the oscillation circuit is controlled according to ON / OFF of the switching element. Data transmission device. 2. A nurse call operation unit, an oscillation circuit which starts operation in accordance with an operation of the nurse call operation unit and whose oscillation frequency changes according to a magnitude of a capacitance component connected as a circuit, and a nurse call operation unit. A data signal generating unit that outputs a data signal composed of a binary signal according to a preset identification code when is operated, a switching element that turns on and off in response to the data signal, and a switch that turns on and off the switching element. A nurse call transmitter comprising: a capacitance component whose connection as a circuit to the oscillation circuit is controlled; and a transmission unit that transmits a signal corresponding to the oscillation frequency of the oscillation circuit. 3. The nurse call transmitter according to claim 2, a receiving unit that receives a signal transmitted from the nurse call transmitter, and the identification code is determined from the received signal and the identification is determined. A nurse call management unit for performing a display and / or a warning according to the code.