JP3144964B2 - Data carrier system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data carrier system using an electromagnetically coupled data carrier having no power supply, and particularly to a case where bidirectional data communication is performed between a data carrier and a fixed facility. The present invention relates to a technique in which a plurality of fixed facilities are arranged close to each other and a state in which mutual interference occurs is considered.

[0002] The term "data carrier" as used in the present invention refers to an IC card, an industrial data tag, a name plate with an ID function, various prepaid cards, etc., and a distance of more than a few centimeters from a communication terminal called a fixed facility. It refers to a device that performs data communication without contact over a distance. Further, the present invention particularly relates to a countermeasure for preventing interference between fixed facilities, which is generated when a plurality of fixed facilities are juxtaposed within a short distance and each fixed facility communicates with a data carrier. .

[0003]

2. Description of the Related Art Conventionally, as a system using an electromagnetic coupling type data carrier, various systems have been proposed depending on a communication system, a power supply system and the like. First, there are two types of power supply systems: a built-in battery system in which the data carrier itself has a built-in battery, and a non-powered system that receives an electromagnetic signal transmitted from a fixed facility without a built-in battery and uses a rectified voltage as a power source. There is.

[0004] As a communication system, a one-way communication system in which data stored in a data carrier is transmitted to a fixed facility only, and data stored in the data carrier is rewritten by data transmitted from the fixed facility, There is a two-way communication system that transmits data from a carrier to a fixed facility.In the two-way communication system, two frequencies where the frequency of the AC magnetic field generated by the fixed facility and the frequency of the AC magnetic field generated by the data carrier are different. There is a scheme and a one-frequency scheme using the same frequency. The present application is mainly directed to a non-power-supply two-way communication system and a one-frequency system.

Next, conventional examples of each of the above methods will be described. First, as a bidirectional communication system to which the present invention is applied, there are JP-A-2-291091, JP-A-3-273465, JP-A-4-692, and the like. Japanese Patent Publication No. 3-12353 discloses an example of a bidirectional communication system without power supply which is similar to the present invention but employs a dual frequency system.
Furthermore, Japanese Patent Publication No. 3-19591, Japanese Patent Publication No. 3-12352, US Pat.
No. 24, US Pat. No. 4,129,855, etc., which are one frequency system without power supply particularly related to the present invention, but Japanese Patent Publication No. 3-25832 is an example of only one-way communication system.

[0006] However, each of the above-mentioned prior arts is related to a system using one fixed facility and one data carrier, and a plurality of fixed facilities are juxtaposed within a short distance, and each fixed facility is provided separately. No consideration is given to the interference problem between fixed facilities, which occurs when communication with individual data carriers is performed in parallel. Accordingly, the interference problem between fixed facilities, which is the main object of the present invention, will be examined for each of the above-mentioned conventional examples.

Conventionally, in a system using an electromagnetically coupled data carrier without a power source, only a system that performs one-way communication from a data carrier to a fixed facility has been put to practical use. In many of these systems, the alternating magnetic field generated by the fixed facilities is in an unmodulated state, and the combined field of the alternating magnetic fields generated by the fixed facilities is also in an unmodulated state, so that the fixed facilities interfere with each other. Data communication does not go wrong.

In a system in which the frequency of the AC magnetic field generated by the fixed facility is different from the frequency of the AC magnetic field transmitted from the data carrier, the frequency of the AC magnetic field generated by the data carrier is fixed. Since the frequency of the AC magnetic field generated by the facility is different, the data signal is separated by using filter technology. Therefore, the influence of the alternating magnetic field generated by the fixed facility in the vicinity can be eliminated.

On the other hand, the non-power-supply, single-frequency, two-way communication system of the present invention modulates an AC magnetic field generated from a fixed facility to transmit data to a data carrier. Since the magnetic field fluctuates, the induced electromotive force also changes in the antenna coil of an adjacent fixed facility that is far away. Since the frequency of the AC magnetic field generated by the data carrier is the same as the frequency of the AC magnetic field generated from the fixed facility, the change in the induced electromotive force and the change in the induced electromotive force due to the alternating magnetic field generated from the data carrier are different. Discrimination was very difficult, and it was considered impossible to read out the correct data from the data carrier.

On the other hand, the applicant of the present application has filed Japanese Patent Application No.
No. 0917 has already proposed a data carrier system aiming at solving the above-mentioned interference problem between fixed facilities. That is, the gist of the above data carrier system is as follows. In other words, in a data carrier system using an electromagnetic coupling type data carrier with no power supply, two-way data communication can be performed between the fixed facility and the data carrier, and a plurality of fixed facilities are arranged in close proximity. However, in order to prevent interference between the fixed facilities, a synchronous means for making the frequency and phase of the alternating magnetic field generated from the fixed facilities the same among a plurality of fixed facilities is provided, and the data carrier is provided with Paying attention to the fact that the phase of the power induced in the antenna of the fixed facility differs from the phase of the power guided from the adjacent fixed facility by 90 ° due to the generated AC magnetic field, the synchronization is performed using the synchronization signal controlled by the synchronization means. Data carrier system that detects and removes induced power from adjacent fixed facilities and extracts only induced power from data carriers. There has been disclosed.

[0011]

However, considering a case where a data carrier system provided with the above-described means for preventing interference between fixed facilities (that is, means for removing interference guidance signals) is actually installed, the manufacturer of the system is considered. However, it is necessary to adjust the interference guidance signal removing means after a plurality of fixed facilities are installed adjacent to each other according to the conditions desired by the user.

In this case, as an adjustment method, a noise signal (an interference signal, which cannot be completely removed, obtained by passing an induction power (ie, an interference induction signal) induced from the adjacent fixed facility to the antenna through a synchronous detection circuit. This is performed by adjusting the phase of the synchronization signal so that the level of the signal component is a minimum. However, when performing the above adjustment, there is a problem that it is difficult to perform the adjustment operation unless the interference induction signal is constantly input to the synchronous detection circuit.

Accordingly, an object of the present invention is to solve the above problem and provide a data carrier system capable of constantly supplying an interference signal required for adjustment to a synchronous detection circuit when adjusting interference induced signal removing means. To provide.

[0014]

SUMMARY OF THE INVENTION The present invention basically employs the following technical configuration to achieve the above object. That is, an electromagnetic coupling type data carrier and a fixed facility for performing bidirectional data communication between the data carrier, the fixed facility is a data signal induced by an AC magnetic field generated by the data carrier, An input signal mixed with an interference induction signal induced by an alternating magnetic field transmitted from another fixed facility is received by the receiving means, and the interference induction signal is discriminated from the input signal to remove the interference induction signal. A data carrier system comprising: an interference guidance signal removing unit that detects only a data signal from a data carrier; and an adjustment unit that adjusts an interference guidance signal removal characteristic of the interference guidance signal removal unit. The facility has a data key having an adjustment signal generating means for generating an adjustment signal used for adjusting the interference induction signal removing means. A rear system.

[0015]

In the data carrier system according to the present invention, a plurality of fixed facilities are arranged in parallel, and by passing a predetermined data carrier between the fixed facilities, the data carrier and the specific fixed facility are arranged. In the meantime, when performing two-way data communication, in order to adjust the interference guidance signal removal characteristics of the interference guidance signal removal means provided in each of the fixed facilities, between the fixed facilities, By transmitting adjustment signals for adjustment, one fixed facility receives the adjustment signal from another fixed facility and adjusts the characteristic of the interference induction signal removing means in its own fixed facility to an optimum level. If another fixed facility adjacent to the facility does not exist at the time of the adjustment, the fixed facility itself transmits the adjustment signal, and the predetermined fixed By to receive the burner performs the same adjustment operation, and adjusts to an optimum level characteristic of in the interference induced signal removing means in its fixed facilities.

Therefore, the adjustment signal transmitted from each fixed facility is made a pseudo signal similar to the data signal generated for the data carrier when each fixed facility is actually operated, so that more practical adjustment can be performed. The operation can be performed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific example of a data carrier system according to the present invention will be described in detail with reference to the drawings. FIG.
Shows the configuration of one specific example of the principle configuration of the data carrier system 800 according to the present invention and the configuration of the first specific example of the present invention. The fixed facility 200 includes a carrier 16 and a fixed facility 200 for performing bidirectional data communication with the data carrier 16. The fixed facility 200 includes a data signal induced by an AC magnetic field generated by the data carrier 16, and other data. Receiving the input signal mixed with the interference induction signal induced by the AC magnetic field transmitted from the fixed facilities 200 ′, 200 ″, etc., and discriminating the interference induction signal from the input signal, An interference induction signal removing unit 300 that removes the interference induction signal and detects only the data signal from the data carrier 16, Adjusting means 4 included in the interference-guiding signal removing means 300 for adjusting the interference-guiding signal removing characteristic
00, the fixed facility 200 has an adjustment signal generating means 500 for generating an adjustment signal for use in adjusting the interference guidance signal removing means 300. It is shown.

Here, the configuration of the first specific example in the data carrier system 800 according to the present invention will be described more specifically with reference to the block diagram of FIG.
That is, FIG. 1 shows a data carrier system 8 according to the present invention.
FIG. 2 is a block diagram showing an outline of a circuit configuration of an AC signal generating circuit 100. Basically, an AC signal generating circuit 100 is configured by an oscillator 1 and a switch 2, and an output signal of the oscillator 1 is supplied to an ACin terminal from the outside by connecting a switch. Is selected as an AC signal AC of the fixed facility 200.

The AC signal AC is supplied from a signal output terminal ACout to an ACin terminal of another fixed facility 200 'adjacent thereto.
As a result, the two fixed facilities 200 and 200 'can use exactly the same AC signal AC. Of course, when there is no possibility that the two fixed facilities 200 and 200 'may interfere with each other because of a long distance,
The output signal of the oscillator 1 built in each fixed facility 200 can be used. In the present embodiment, the AC signal AC is distributed to the modulation circuit 3, the voltage adjustment circuit 7, and the phase adjustment circuit 11 included in the interference induction signal removal means 300.

The modulation circuit 3 modulates the AC signal AC in accordance with output data DATAout provided from the information processing circuit 17, that is, data to be transmitted to a data carrier. The modulation method includes frequency modulation, phase modulation, amplitude modulation, and the like.
Any of them may be used, but the most effective use of the effects of the present invention is a binary amplitude modulation system, and the following description is based on that system.

The antenna driving circuit 4 power-amplifies the output signal of the modulation circuit 3 and drives the antenna 6 via the current / voltage converter 5. The antenna 6 is constituted by a series resonance circuit of an antenna coil and a capacitor, and the resonance frequency of the antenna 6 matches the frequency of the AC signal AC. As described above, the antenna 6 outputs the AC magnetic field φ1, and the data carrier 16 receiving the energy returns the AC magnetic field φ2.

The current of the antenna 6 is converted into a voltage by the current-to-voltage converter 5 and the first input voltage of the subtraction circuit 8
Be Vo. The first input voltage Vo is generally represented by the following equation (1). Vo = kV1sin (ω0T) −kΔV1sin (ω0t) + kVnsin (ω0t−π / 2) (1) In the above equation, V1 is a voltage amplitude, ω0 is an angular frequency,
k is a constant.

Next, the second input voltage of the subtraction circuit 8 is an AC voltage Vs obtained by adjusting the voltage of the AC signal AC by the voltage adjustment circuit 7. If the voltage adjustment circuit 7 is adjusted so that the AC voltage Vs becomes equal to the first term of the equation (1), the output voltage of the subtraction circuit 8 when data is not transmitted from the fixed facility is expressed by the equation (1). It is represented only by the second and third terms.
That is, it does not include a voltage corresponding to a current directly driven by the antenna driving circuit 4. Therefore, the voltage amplitude becomes small and can be amplified by the amplifier circuit 9. The output voltage of the amplifying circuit 9 depends on the interference induction signal removing means 3
The output voltage Vr of the phase adjustment circuit 11 included in the clock signal 00 is guided to a synchronous detection circuit 10 which uses the output voltage Vr as a synchronous signal, and is rectified and detected.
At this time, the yield of the third term in the equation (1) is 0% in principle, but a phase shift may occur due to an error factor of a circuit such as the amplifier 9. In order to compensate for this phase shift and reduce the noise term yield to 0%, the phase adjustment circuit 11 is adjusted to change the phase of the synchronization signal. Thereby, the output signal of the synchronous detection circuit 10 can include only the component induced by the data carrier.

If there is no subtraction circuit 8 and the output voltage of the current-to-voltage converter 5 is directly input to the amplification circuit 9, the amplification degree cannot be increased because the output of the amplification circuit is immediately saturated. In addition, the slight deviation of the phase accuracy of the synchronization signal in the synchronous detection greatly changes the yield with respect to the first term of the equation (1), and the error generated thereby becomes relatively large. Therefore, the roles of the voltage adjustment circuit 7 and the subtraction circuit 8 are as follows.
It is extremely important to improve the reliability of demodulation of data transmitted from a data carrier.

The detection output of the synchronous detection circuit 10 has a waveform as shown in the waveform (A) of FIG. 2, but the carrier component is removed by the low-pass filter 12, and as shown in the waveform (B) of FIG. A low-frequency component and a rectangular wave are combined. Still at this stage, information on the distance between the data carrier 16 and the fixed facility 200 is superimposed on the signal. The information on the distance is specifically the magnitude of the electromotive force Δv1, and a DC voltage having a magnitude proportional to the magnitude is superimposed. The superimposed DC voltage changes as the distance between the data carrier and the fixed facility changes, which causes the input operating point of the waveform shaping comparator circuit to be undefined.

In this embodiment, the output signal of the low-pass filter 12 is differentiated by a differentiating circuit 13 in order to remove the superimposed DC voltage.
Is configured to be differentiated by This allows
Low frequency signals due to relatively slow changes, such as the data carrier approaching or moving away from the fixed facility, can be removed, but abrupt changes such as bit changes in digital data transmitted by the data carrier may be degraded. Without being transmitted, resulting in a differentiated waveform as shown in waveform (C) of FIG.

The differentiated waveform is transmitted to the waveform shaping circuit 15 via the gate circuit 14. At this time, the gate circuit 14 is controlled by a gate control signal MASK output from the information processing circuit 17, and when the fixed facility is transmitting data, that is, when the information processing circuit 17 is transmitting output data DATAout. Do not pass signals. Thus, the signal input to the waveform shaping circuit 15 is only the signal sent from the data carrier. The waveform shaping circuit 15 generates a rectangular wave data signal as shown in the waveform (D) of FIG. 2 by making the signal rise with a plus pulse of the differential waveform and making it fall with a minus pulse. The data signal is input data DATAin
Is sent to the information processing circuit 17.

The above is disclosed in Japanese Patent Application No. 4-60917, which is a prior application for the present invention. Further, in the data carrier system 800 according to the present invention, an adjustment signal generation means 500 is provided, and the adjustment signal generation 500 includes, for example, the adjustment signal generation circuit 18 and the switch means 25. And the adjustment operation is necessary because the interference induction signal elimination characteristic in the interference induction signal elimination means 300 of the fixed facility 200 is initially adjusted or deviated from a set value. In addition to the switch means 25 which can be operated by the operator to enter the adjustment operation, an adjustment signal output from the adjustment signal generation circuit 18 is supplied to the modulation circuit 3. As a result, the information transmitted from the data carrier 16 and the interference induction signal mixed from the adjacent fixed facility are transmitted to the The interference-induced signal removal characteristic of the interference-induced signal removal means 300 is adjusted so that the interference-induced signal can be removed by the operation of the interference-induced signal removal means 300 as described later. .

That is, when the switch 21 is connected to the modulation circuit 3, the adjustment signal is transmitted from the transmission / reception antenna 61 of the antenna means 6 to the adjacent fixed facility 200 ′ via the antenna drive circuit 4. It is possible to transmit the adjustment signal. On the other hand, in the opposite case, the modulation signal transmitted from the antenna means of the adjacent fixed facility 200 'is received, and the interference induction signal removal characteristic in the own fixed facility 200 is used for adjustment. is there.

On the other hand, a second embodiment of the present invention is shown in FIG. 3, and in the second embodiment, when viewed from a predetermined fixed facility, an adjacent fixed facility is used. An example of a method for adjusting the interference-induced signal removal characteristic when the modulated signal for adjusting the interference-induced signal removal characteristic in the fixed facility cannot be received from the adjacent fixed facility, because 200 ′ or 200 ″ does not exist. It shows.

That is, in FIG. 3, in the data carrier system 800, the adjustment signal generating means 500
Is, for example, the adjustment signal generation circuit 18 and the switch means 25
Since the interference guidance signal removal characteristic in the interference guidance signal removal means 300 of the fixed facility 200 is initially adjusted or deviated from a set value, the adjustment operation is not performed. In addition to the switch means 25 which can be operated by the operator to enter the adjustment operation when necessary, the adjustment signal output from the adjustment signal generation circuit 18 is transmitted to the modulation circuit 3. And a switch 21 for selectively connecting to the modulation circuit 19 and a newly provided modulation circuit 19.

In the case where the output of the adjustment signal generating circuit is connected to the newly provided modulation circuit 19 in the switch means 21, the receiving antenna 61 of its own fixed facility 200 is used.
The adjustment signal is sent through the adjustment antenna 62 provided for adjustment to the
However, the self-generated adjustment signal is used to adjust the interference-induced signal removal characteristic of the fixed facility.

Therefore, in the data carrier system 800 according to the present invention, a further antenna driving circuit 20 is connected to the modulation circuit 19, and the output of the antenna driving circuit is newly transmitted to the antenna means 6. The adjustment signal generated from the adjustment signal generation circuit 18 is radiated from the adjustment antenna 62 and received by the own reception antenna 61, and is connected to the adjustment antenna 62 provided. Are used to adjust the interference-induced signal removal characteristics in the own fixed facility 200. next,
The configuration and operation of the interference induction signal removing means 300 according to the present invention will be described.

That is, the interference induction signal removing means 300
Detection means 700 comprising the above-described synchronous rectification circuit 10 and low-pass filter 12, adjustment signal determination means 600 including an adjustment signal determination circuit (a pseudo signal determination circuit described later) 23, and phase adjustment means 40 including a phase adjustment circuit 11
0 and display means 24,
The low-pass filter 12 in the detection means 700
One of the outputs is connected to an adjustment signal determination unit 600 composed of an adjustment signal determination circuit 23 that determines the output level of the adjustment signal used in the present invention. Is connected to display means 24 for displaying the residual level of the adjustment signal.

On the other hand, the other input of the detecting means 700 comprising the synchronous rectifier circuit 10 and the low-pass filter 12 is connected to the phase adjusting circuit 11 according to the present invention. The adjustment signal determination means 60
In response to the 0 output signal level, the phase of the AC signal supplied to the synchronous rectifier circuit 10 is finely adjusted.

In the phase adjustment circuit 11 according to the present invention, in order to adjust a plurality of types of interference induction signals having different phases generated from a plurality of adjacent fixed facilities, if the phase is adjusted to one phase, other adjustments are made. Is shifted, and it is impossible to completely remove the phase difference and make the remaining amount of the adjustment signal zero. Therefore, in the present invention, the interference induction signal removal is adjusted mainly by the phase adjustment as described above, but there are many that cannot be removed, and in that case, the gain is adjusted by adjusting the gain. It is intended to finally remove the remaining amount of the adjustment signal that cannot be removed by the method.

Accordingly, the first or second embodiment of the present invention
As shown in FIG. 1 or FIG. 2 in the specific example, in addition to the adjusting means 400 by the phase adjusting circuit 11 provided in the interference induction signal removing means 300, for example, It is desirable to provide a gain adjusting means 400 'comprising a gain adjusting circuit 22 for adjusting the gain.

The gain adjustment means 400 'adjusts the gain of the amplifier circuit 9 in response to the output signal level of the adjustment signal determination means 600. FIG. 4 is a more specific circuit diagram showing the configuration of the first and second specific examples according to the present invention shown in FIG. 1 or FIG. That is, in FIG. 4, the transmission circuit 1 is composed of a crystal oscillator having a C-MOS inverter as an amplifier and a band-pass filter.
An extremely coherent AC signal can be generated by removing the distortion of the waveform included in the oscillation output of the crystal oscillator using a band-pass filter.

The modulation circuit 3 is realized by an inverting amplifier using an operational amplifier. A part of the feedback resistor is turned on / off by a transmission gate, and the amplitude of the AC signal is modulated in two stages by changing the amplification degree. At this time, the control signal of the transmission gate is output data DATAout
It is. The antenna driving circuit 4 is configured by a voltage follower circuit of a power operational amplifier.

The current-voltage conversion circuit 5 is realized by a transformer. The number of primary windings of this transformer is not so large, and care must be taken so as not to hinder power supply to the antenna 6. The antenna 6 is installed in a place away from the main body of the fixed facility using a coaxial cable,
It is composed of a series resonance circuit of an antenna coil and a capacitor. The capacitor is composed of a fixed capacitor and a variable capacitor connected in parallel, and the resonance condition can be adjusted by the variable capacitor.

The voltage adjusting circuit 7 is constituted by an inverting amplifier circuit of an operational amplifier, and its feedback resistance is a variable resistance. By adjusting this, the amplitude of the output voltage can be changed. The subtraction circuit 8 is a high input impedance differential amplifier configured using two operational amplifiers.
The differential amplifier has not only a subtraction function but also the function of the amplifier circuit 9.

The variable resistor VR for gain adjustment provided in one differential amplifier corresponds to the gain adjustment circuit 22 in FIG. 1 or FIG. Synchronous detection circuit
Reference numeral 10 denotes an operational amplifier circuit that saturates and amplifies the synchronization signal Vr to generate a rectangular synchronization signal, and two Cs that convert the synchronization signal into two gate control signals having a good rising characteristic and having a complementary relationship with each other. -MOS Inverter, two transmission gates turned on and off by the gate control signal, and a differential amplifier composed of an operational amplifier. In order for the waveform of the output signal of the synchronous detection circuit to be a full-wave rectified waveform as shown in FIG. 2 (waveform B), the phase of the two gate control signals must be equal to the phase of the input signal of the synchronous detection circuit 10. Must match. Therefore, means for adjusting the phase of the synchronization signal Vr is required.

The phase adjusting circuit 11 is composed of two phase sending circuits each composed of an operational amplifier. The first phase feed circuit delays the phase of the AC signal AC by 90 °, and the subsequent phase feed circuit advances the once delayed signal by 90 ° so that there is no phase shift in total. However, by making the constant of the phase shift circuit of the subsequent stage variable, the shift amount can be adjusted in the plus direction or the minus direction near 0 °.

The variable resistor VR2 provided in the subsequent phase feed circuit corresponds to the phase adjusting means 400 in FIG. 1 or FIG. Low-pass filter 12
Is constituted by directly connecting two stages of a double feedback type active low-pass filter using an operational amplifier, and the differentiating circuit 13 is composed of a capacitor input type differentiating circuit and a voltage follower circuit of the operational amplifier.

The gate circuit 14 is constituted by a transmission gate which is turned on / off by a gate control signal MASK output from the information processing circuit 17, and cuts off the differential waveform by directly connecting the output of the differentiating circuit 13 to the negative power source V-. Can be done. The waveform shaping circuit 15 is a comparator using an operational amplifier. Since the comparator has a hysteresis characteristic,
The output is raised or lowered by a plus pulse and a minus pulse output alternately from the differentiating circuit 13.
When data is being sent from the fixed facility, a negative power supply voltage is input to the comparator by the gate circuit 14, so that the output voltage is kept at a low level. Therefore, reception of data from the data carrier always starts at a low level.

On the other hand, the adjustment signal generation means 18 divides the frequency of the AC signal AC and adjusts the modulation wave signal Dm for adjustment signal at an arbitrary period.
Is a frequency dividing circuit for generating
Is OFF, the reset terminal is in the “H” state, and is in the non-operating state. When the adjustment signal is generated at the time of adjustment, the switch 25 is turned on, the adjustment signal generation circuit 18 is activated, and the AC signal A shown in FIG.
C is frequency-divided to output a modulation signal Dm as shown in FIG. 4B, and the transmission gate of the modulation circuit 3 is set to O.
N / OFF, and an adjustment signal (pseudo signal) shown in FIG.
Ds is output.

The adjustment signal judgment circuit 23 constituting the adjustment signal judgment means 600 used in the present invention comprises a peak hold circuit 231 and an analog / digital converter 232.
And an analog / digital converter 23
2 includes a plurality of division resistors R1 to Rn and comparators CMP1 to CMPn connected to the respective division points.

The signal output of the low-pass filter 12 is held by the peak hold circuit 231, and is converted by the analog / digital converter 232 into a digital signal corresponding to several ranks of adjustment levels. Further, the display means 24 used in the present invention is constituted by a plurality of LEDs (LED1 to LEDn) for indicating the adjustment level, and the LE 24 is controlled in accordance with the output of the analog / digital converter 232.
By changing the number of lightings of D (LED1 to LEDn), it is possible to read the adjustment level based on the adjustment signal output from the low-pass filter 12.

In the data carrier system according to the present invention, as described above, a plurality of the fixed facilities 200 are arranged adjacent to each other with a predetermined interval therebetween. Receiving the adjustment signal transmitted from the adjustment signal generating means 500 provided in the other fixed facility 200 ′ by the receiving means 6 provided in the own fixed facility 200, thereby causing interference induction signals with each other. Is configured so that the removal adjustment can be performed.

The adjustment signal transmitted from the adjustment signal generating means 500 used in the present invention is a pseudo signal similar to the interference induction signal generated when the fixed facility 200 actually operates. Something is desirable. Therefore, in the present invention, it is desirable that the adjustment signal generating means 500 has a function of generating the pseudo signal as described above.

The adjustment signal generating means 500, which is the pseudo signal generating means, generates a pseudo signal obtained by continuously and periodically modulating an AC signal for generating an AC magnetic field of the fixed facility 200. It is preferable to be constituted.
Further, the data carrier system 800 in the present invention
In the above, the fixed facility 200 can supply the interference induction signal to another adjacent fixed facility 200 ′ by supplying the pseudo signal to its own transmitting antenna 61, and The fixed facility 200 may have a separate antenna 62 for adjustment, and may be configured to supply the pseudo-signal to the own receiving antenna 61 via the adjustment antenna 62 to supply an interference induction signal. good.

Therefore, in the data carrier system 800 according to the present invention, in the fixed facility 200,
When adjusting the interference-induced signal removal characteristic of the interference-induced signal removal means 300, the signal transmitted from the pseudo signal generation means 500 provided in the same fixed facility 200 or another adjacent fixed facility 200 ′ is provided. It is configured to execute a predetermined adjustment operation using a pseudo signal.

On the other hand, in the data carrier system 800 according to the present invention, the interference induction signal removing means 300 of the fixed facility 200 is replaced by the pseudo signal generating means 50.
It includes a pseudo signal detecting means 700 for detecting the level of the pseudo signal generated from 0, and the interference induction signal removal characteristic of the fixed facility 200 is adjusted according to the output of the pseudo signal detecting means 700. Things.

Further, the interference induction signal removing means 300 of the fixed facility 200 further includes the pseudo signal detecting means 7.
A pseudo signal determination unit 600, a phase adjustment unit 400, and a display unit 24 for determining the level of the output data 00 are provided. Also, in the present invention,
The fixed facility 200 has an amplifier 9 for amplifying the received adjustment signal and a gain adjustment unit 400 for adjusting the gain of the amplifier 9, and the gain adjustment unit 400 according to the output level of the adjustment signal determination unit 600, It is desirable to be configured to perform gain adjustment.

In the present invention, the pseudo signal judging means 6
00 compares the detected interference signal with a predetermined reference level and outputs the result, and the pseudo signal determination means 600 compares the detected interference signal with a predetermined reference level and outputs the result. It is desirable that the result be output as a plurality of types of level signals. Next, FIG.
Thus, the adjustment signal (interference signal 9), which is the basic operation of the present invention,
Is specifically described.

In the specific example of the data carrier system 800 according to the present invention, the receiving antenna 61 of the fixed facility 200 receives the modulated signal including the pseudo signal as an example of the adjustment signal. Then, a pseudo signal Vo having a waveform as shown in FIG. 6A is detected from the current-voltage converter (IV converter) 5. On the other hand, the output Vs of the voltage adjustment circuit 7 has a waveform as shown in FIG. 6B, and both the pseudo signal Vo and the output Vs are input to the subtraction circuit 8.

An output waveform Vc as shown in FIG. 6C is output from the output terminal of the subtraction circuit 8, and is input to the synchronous rectification circuit 10 via the amplification circuit 9. On the other hand, the synchronous rectifier circuit 10
The other input terminal section has a synchronous rectification clock Vr output from the phase adjustment circuit 11 as shown in FIG.
Is input.

Then, in the synchronous rectifier circuit 10, synchronous detection of the output waveform Vc of the subtraction circuit is performed, and the synchronous rectifier circuit output Vd as shown in FIG. Is obtained. When the output signal Vd to the synchronous rectifier circuit 10 is passed through the low-pass filter 12, an output waveform Vf of the low-pass filter 12 as shown in FIG.

The low-pass filter 1 shown in FIG.
The signal level difference h in the output waveform Vf of No. 2 indicates the remaining amount of the adjustment signal or the remaining amount of the pseudo signal (the remaining amount of the phase component detected by the synchronous detection) according to the present invention. If the interference-induced signal removal characteristic of the fixed facility 200 is adjusted, the signal level difference h in the output waveform Vf of the low-pass filter 12 becomes 0, and FIG.
The output waveform should be as shown by the dotted line in FIG.

Accordingly, the signal level difference h in the output waveform Vf of the low-pass filter 12 is detected by the pseudo signal judging means 23, and the phase adjustment circuit 11 is adjusted in such a direction as to minimize the signal level difference h. This is to adjust the phase. However, even if the optimal adjustment of the phase adjustment circuit 11 is performed, since a plurality of interference induction signals having different conditions are input from a plurality of adjacent fixed facilities, perfect phase adjustment is impossible, and some pseudo signal Is present as a noise signal.

The noise signal is removed by adjusting the gain adjustment circuit 22 of the amplifier 9. In the present invention, mainly, the adjustment of the interference induction signal removal characteristic is performed by the phase adjustment circuit 11, and a small difference h that cannot be reduced to 0 in the phase adjustment circuit 11 is adjusted by the gain adjustment circuit 22. It is normal to adjust the gain.

Of course, in the actual adjustment operation, it is difficult to make the signal level difference h in the output waveform Vf of the low-pass filter completely zero only by adjusting the phase adjustment circuit 11, so that the pseudo signal determination means In step 600, an appropriate threshold value is set, and if a signal level difference h exceeding the threshold value is detected, the gain of the gain adjustment circuit 22 is manually or automatically reduced to reduce the signal. An adjustment operation for adjusting the level difference h so as to be equal to or less than the threshold value is performed.

In the specific example of the present invention, the gain adjustment is performed carefully, since there is a risk that the original signal to be transmitted may be erased as a result of the gain adjustment. On the other hand, if the gain is set too high, there is a risk that the LED in the display means may be turned on by noise, so that it is necessary to set conditions that satisfy the above two conditions. It becomes important.

Next, an example of a method of adjusting the interference-induced signal removal characteristic of the interference-induced signal removal means 300 in the data carrier system 800 according to the present invention will be described. The fixed facility of the data carrier system according to the present invention is used for a communication device of a ski auto gate system, for example, as shown in FIG. If there is, the above-described adjustment operation is required.

That is, when the ski gate is moved or the communication performance is significantly deteriorated, as a part of the maintenance of the fixed facility, the interference guided signal removal means of the fixed facility removes the interference guided signal. It is necessary to adjust the characteristics. For example, fixed facilities require such adjustments at the beginning of the season and after the ski gate moves.

The following is an example of a procedure for adjusting a fixed facility, which is executed after the installation of the ski gate is completed.

(1) Prior to the adjustment, a warm-up at power-on is performed. That is, the communication device TB often has a built-in compensation circuit in order to minimize the deterioration of the communication performance due to a change in the external environment.
The adjustment operation is performed after the time required for the circuit to stabilize has elapsed.

(2) Multiple operation When a plurality of gates are used in close proximity, as shown in FIG. 6, a reference signal is supplied to all gates from one common clock source. In this case, one common clock generation source CLB is provided for one group of a plurality of operating gates. The common clock generation source CLB is built in one gate 200 in the group (master) and supplies a reference signal to the other gate 200 ′ (slave) in the group via the clock cable CAB. I do.

(3) Adjustment for Interference Cancellation When a plurality of gates are operated at the same time, a transmission signal for a data carrier from an antenna of a certain gate becomes noise at the time of reception for an antenna of another gate. An adjustment is made to minimize. That is, among the gates in the same group, the interference switches (switch 25 in FIG. 1) of all the gates are turned ON except for the adjustment of the removal of the interference induction signal. By turning on the interference switch, the antenna means 6 is turned on as shown in FIG.
The pseudo transmission signal shown in (C) is continuously output.
The variable resistor for interference removal (VR2) provided in the phase adjustment circuit 11 in FIG. 4 is slowly turned while looking at a level meter which is a specific example of the display means 24, and the number of lit LEDs of the level meter Is set to the state that minimizes

(4) Sensitivity adjustment This is an adjustment operation performed on the gain adjustment circuit 22 and the amplification circuit 9, and adjusts the sensitivity of the received signal from the data carrier so that a signal below a predetermined level is insensitive. It is to adjust. First, the number of lit LEDs of the level meter, which is an example of the display means 24, is checked. Then, the variable resistor VR3 is rotated as a gain adjusting means 400 'provided in the subtraction circuit 8 including the amplification circuit 9 of FIG. 4 so as to adjust the number of lit LEDs of the level meter to zero.

Although the above description has been given of the case of manual adjustment as the phase adjustment and sensitivity adjustment, the present invention is not limited to this case. As shown by a dotted line in FIG.
3 may be automatically performed in accordance with the output of (3).

[0072]

The data carrier system according to the present invention employs the above-mentioned technical configuration. Therefore, when the data carrier system provided with the interference prevention means between the fixed facilities is actually installed, After the manufacturer of the system has installed a plurality of fixed facilities adjacent to each other according to the conditions desired by the user, it is necessary to adjust the interference prevention means (that is, the interference guidance signal removal means). In the adjustment, the interference signal necessary for the adjustment can always be supplied to the synchronous detection circuit, so that it is possible to obtain a data carrier system capable of executing the adjustment operation extremely easily and quickly.

Further, according to the present invention, when the internal antenna is provided, even if another fixed facility is not operating,
It is possible to intentionally transmit a pseudo signal from the antenna provided in the fixed facility to the own receiving antenna, thereby forcibly adjusting the interference induction signal removal characteristic in the fixed facility. There is also the effect of saying.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of the configuration of the data carrier system according to the present invention.

FIG. 2 is a diagram showing an example of a signal waveform in a specific example of the data carrier system according to the present invention.

FIG. 3 is a block diagram showing another example of the configuration of the data carrier system according to the present invention.

FIG. 4 is a circuit diagram showing a specific example of a configuration of a data carrier system according to the present invention.

FIG. 5 is a diagram showing an example of a signal waveform on a transmission side in the data carrier system according to the present invention.

FIG. 6 is a diagram showing an example of a signal waveform on a receiving side in the data carrier system according to the present invention.

FIG. 7 is a diagram showing a signal connection state when a plurality of fixed facilities are arranged in the data carrier system according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Oscillator 2, 21, 25 ... Switch means 3, 19 ... Modulation circuit 4, 20 ... Antenna drive circuit 5 ... Current-voltage converter 6 ... Antenna means 61 ... Transmission / reception antenna 62 ... Adjustment antenna 7 ... Voltage adjustment circuit 8 ... Subtraction circuit 9 Amplifier circuit 10 Synchronous rectifier circuit 11 Phase adjustment circuit 12 Low-pass filter 13 Differentiator circuit 14 Gate circuit 15 Waveform shaping circuit 16 Data carrier 17 Information processing circuit 18 Adjustment signal generation circuit Pseudo signal generation circuit 22 ... Gain adjustment circuit 23 ... Adjustment signal judgment circuit, pseudo signal judgment circuit 24 ... Display means 100 ... AC signal generation circuit 200 ... Fixed facility 300 ... Interference induction signal removal means 400 ... Adjustment means 500 ... Adjustment signal generation Means 600 ... Adjustment signal determination means, pseudo signal determination means 700 ... Adjustment signal detection means, pseudo signal detection means 00 ... data carrier system

Claims (18)

(57) [Claims] 1. An electromagnetically coupled data carrier and a fixed facility for performing bidirectional data communication with the data carrier, wherein the fixed facility is configured to transmit data induced by an alternating magnetic field generated by the data carrier. A receiving unit receives an input signal in which a signal and an interference induction signal induced by an AC magnetic field transmitted from another fixed facility are mixed, and discriminates the interference induction signal from the input signal, and Interference-induced signal removing means for removing the signal and detecting only the data signal from the data carrier;
In a data carrier system having an adjusting means for adjusting an interference guiding signal removing characteristic of the interference guiding signal removing means, the fixed facility generates an adjusting signal for use in adjusting the interference guiding signal removing means. A data carrier system comprising an adjustment signal generating means for causing the data carrier to generate an adjustment signal. 2. A plurality of said fixed facilities are arranged adjacent to each other at a predetermined interval, and said fixed facilities are transmitted from said adjustment signal generating means provided in another adjacent fixed facility. 2. The data carrier system according to claim 1, wherein said adjustment signal is received by receiving means provided in said own fixed facility. 3. The fixed facility includes the adjustment signal generating means in its own fixed facility, and stores the adjustment signal transmitted from the adjustment signal generating means in its own fixed facility. 3. The data carrier system according to claim 1, wherein the data carrier system is configured to receive the data by a receiving unit provided. 4. The adjustment signal transmitted from the adjustment signal generating means is a pseudo signal similar to the interference induction signal generated when the fixed facility actually operates. The data carrier system according to any one of claims 1 to 3. 5. The data carrier system according to claim 4, wherein said adjustment signal generating means is a pseudo signal generating means. 6. An electromagnetically coupled data carrier and a fixed facility for performing bidirectional data communication with the data carrier, wherein the fixed facility is configured to receive data induced by an AC magnetic field generated by the data carrier. The signal and the interference induction signal induced by the AC magnetic field transmitted from another fixed facility are discriminated from the input signal mixed with the interference induction signal, the interference induction signal is removed, and the data signal from the data carrier is removed. In a data carrier system having an interference guidance signal elimination means for detecting only the interference guidance signal, the fixed facility is provided with a simulated signal generation means for generating a simulated signal for use in adjusting the interference guidance signal elimination means. A data carrier system characterized by the following. 7. The data carrier system according to claim 6, wherein said pseudo signal generating means generates a pseudo signal obtained by continuously and periodically modulating an AC signal for generating an AC magnetic field of said fixed facility. 8. The data carrier system according to claim 1, wherein the fixed facility supplies the pseudo signal to its own transmitting antenna to supply an interference induction signal to another adjacent fixed facility. . 9. The fixed facility further comprises an antenna for adjustment, and supplies the interference induction signal to its own receiving antenna via the antenna for adjustment of the pseudo signal. 2. The data carrier system according to 2. 10. In the fixed facility, when adjusting the interference guidance signal removal characteristic of the interference guidance signal removal means of the fixed facility via the adjustment means, the same fixed facility or an adjacent fixed facility may be used. 10. The apparatus according to claim 1, wherein a predetermined adjustment operation is performed using the pseudo signal transmitted from the pseudo signal generating means provided in another fixed facility. The data carrier system described in Crab. 11. The interference induced signal removing means of the fixed facility includes a pseudo signal detecting means for detecting a level of the pseudo signal generated from the pseudo signal generating means. 11. The data carrier system according to claim 10, wherein an interference-induced signal removal characteristic of the fixed facility is adjusted according to the output. 12. The apparatus according to claim 1, wherein said interference induced signal removing means of said fixed facility further comprises a pseudo signal determining means for determining a level of output data of said pseudo signal detecting means. 12. The data carrier system according to any one of claims 11 to 11. 13. The fixed facility has an amplifier for amplifying a received adjustment signal and gain adjustment means for adjusting the gain of the amplifier, wherein the gain adjustment means has a gain according to an output level of the adjustment signal determination means. 3. The data carrier system according to claim 2, wherein adjustment is performed. 14. The apparatus according to claim 10, wherein an output of said pseudo signal determination means is connected to an appropriate display means.
13. The data carrier system according to any one of claims 12 to 12. 15. The data carrier system according to claim 14, wherein said pseudo signal determination means compares the detected interference signal with a predetermined reference level and outputs the result. 16. The apparatus according to claim 15, wherein said pseudo signal determining means compares the detected interference signal with a predetermined reference level and outputs the result as a plurality of types of level signals. Data carrier system. 17. The data carrier system according to claim 14, further comprising display means for displaying a plurality of output levels of said pseudo signal determination means. 18. The data carrier system according to claim 14, wherein said interference signal removing means adjusts said adjusting means according to an output level of said pseudo signal determining means.