JP4067638B2 - Data carrier system and interrogator for data carrier system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data carrier system and an interrogator for the data carrier system, and in particular, a data carrier using a non-contact type IC card type data carrier that transmits and receives signals between the interrogator and a responder (data carrier). About the system.
[0002]
[Prior art]
Practical use as a data carrier system (for example, “non-contact IC card system”) in which signals are exchanged between an interrogator and a responder card by an electromagnetic coupling method or an electromagnetic induction method, etc. ) Is widely known.
[0003]
In particular, battery-free non-contact IC card systems that rectify the carrier wave on the responder side and use it as power for the responder have come to be widely used as ID cards, tags for identifying transported items, etc. .
[0004]
In such an electromagnetic coupling type non-contact IC card system, the interrogator modulates the carrier wave generated by the OSC (oscillator) according to the transmission data, amplifies the modulated wave by the driver circuit, and the antenna coil. Is sent to the responder. When the transponder receives the signal from the interrogator with the antenna coil, the rectifier circuit rectifies the carrier wave to obtain power to be used internally, and the demodulator circuit demodulates the received signal and sends it to the data processing circuit for data processing. Data processing is performed by the circuit.
[0005]
By the way, the power used by the answering machine is generated by rectifying the signal received from the interrogator with the rectifier circuit, but the power obtained varies depending on the degree of coupling between the antenna coil of the answering machine and the antenna coil of the interrogator. To do. Therefore, in order to obtain the highest coupling, a capacitor is connected to both antenna coils to form a resonance circuit so as to obtain a high Q value.
[0006]
However, when performing frequency shift keying (FSK) communication that represents “0” or “1” at two different frequencies, there are two transmission signal frequencies, and thus a tuning circuit having a high Q value. However, even if the degree of coupling is increased with a tuning circuit, both frequencies cannot be handled, so sufficient efficiency cannot be obtained.
[0007]
Therefore, as described in Japanese Patent Laid-Open No. 7-131376, power is supplied at one frequency during power feeding, so a high Q value tuning circuit is formed in accordance with this frequency, and another capacitor is connected during data exchange. By connecting, damping is performed to lower the Q value so that both frequencies of FSK can be sufficiently handled.
[0008]
In the conventional data carrier system, the data transmission from the interrogator uses a modulation method such as FSK or PSK in order to increase the power density, and the data transmission from the responder uses the ASK (amplitude shift keying) method. Yes.
[0009]
[Problems to be solved by the invention]
However, the method described in the above publication has a problem that since the tuning frequency is switched between power feeding and data transmission / reception, the determination and switching are required and the apparatus becomes complicated.
[0010]
In view of the above problems, the first object of the present invention is to solve the above problems and to provide a data carrier system capable of obtaining a high degree of coupling while performing FSK communication without requiring any special switching. The purpose is to provide a data carrier interrogator.
The second object of the present invention is to provide a data carrier system and a data carrier interrogator that can solve the above-described problems and obtain a high transmission output without requiring special switching when performing FSK communication. There is.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the data carrier system of the present invention includes a transmission coil and a transmission circuit connected to the transmission coil, and a transmission station that transmits signals at two different frequencies, and the transmission station transmits the signal. In a data carrier system comprising: a receiving coil that receives a magnetic field; and a data carrier that includes a rectifier circuit that extracts power from a signal received by the receiving coil, a plurality of data carriers are provided between the transmitting coil and the transmitting circuit. A reactance element is connected in combination to form a two-wave tuning circuit that tunes to both of the two different frequencies.
Another feature of the data carrier system according to the present invention is that it includes a transmission coil and a transmission circuit connected to the transmission coil and transmits a signal at two different frequencies, and transmits from the transmission station. In a data carrier system having a data carrier comprising a receiving coil for receiving a generated magnetic field and a rectifier circuit for extracting power from a signal received by the receiving coil, a first tuning capacitor is connected to the transmitting coil. A first tuning circuit formed and tuned to one of the two different frequencies, and a second tuning capacitor formed by connecting a second tuning capacitor to a tuning coil and tuned to one of the two different frequencies A tuning circuit; and a reactance element that couples the first tuning circuit and the second tuning circuit, coupled by the reactance element. The tuned circuit is tuned to the other of the two different frequencies.
Another feature of the data carrier system according to the present invention is that the first tuning circuit is a parallel resonant circuit including a first transmission coil and a first tuning capacitor. The tuning circuit is a parallel resonant circuit composed of a second tuning coil and a second tuning capacitor, and both the first and second tuning circuits are tuned to the higher one of the two different frequencies. A circuit in which an adjustment capacitor is connected in series to the second tuning circuit is connected in parallel to the first tuning circuit and is tuned to the lower of the two different frequencies. And
According to another aspect of the data carrier system of the present invention, in the data carrier system described above, the first tuning circuit includes a first transmission coil and a first tuning capacitor. A parallel resonant circuit, wherein the second tuning circuit is a parallel resonant circuit composed of a second tuning coil and a second tuning capacitor, and the first and second tuning circuits are both different from each other. Tuned to the lower one of the two frequencies, a circuit in which the adjustment coil is connected in series to the second tuning circuit is connected in parallel to the first tuning circuit, and the higher frequency of the two different frequencies is Is also characterized by being synchronized.
According to another aspect of the data carrier system of the present invention, in the data carrier system described above, the first tuning circuit includes a first transmission coil and a second tuning capacitor. A series column resonance circuit, wherein the second tuning circuit is a series resonance circuit including a second tuning coil and a first tuning capacitor, and the first and second tuning circuits are both different from each other. Tuned to the higher one of the two frequencies, a circuit in which the adjustment coil is connected in parallel to the second tuning circuit is connected in series to the first tuning circuit, and the lower frequency of the two different frequencies It is also characterized by being synchronized.
According to another aspect of the data carrier system of the present invention, in the data carrier system described above, the first tuning circuit includes a first transmission coil and a second tuning capacitor. A series resonant circuit, wherein the second tuning circuit is a series resonant circuit including a second tuning coil and a first tuning capacitor, and the first and second tuning circuits are both different from each other. Tuned to the lower one of the two frequencies, a circuit having a tuning capacitor connected in parallel to the second tuning circuit, connected in series to the first tuning circuit, and the higher of the two different frequencies It is also characterized by being synchronized.
According to another aspect of the data carrier system of the present invention, in the data carrier system described above, the first tuning circuit includes a first transmission coil and a second tuning capacitor. A parallel resonant circuit, wherein the second tuning circuit is a series resonant circuit composed of a second tuning coil and a first tuning capacitor, and the first and second tuning circuits are both different from each other. A circuit having a tuning coil connected in parallel to the second tuning circuit is connected to the first transmission coil and the first tuning capacitor of the first tuning circuit. It is characterized in that it is also tuned to the lower of the two different frequencies by intervening between them.
According to another aspect of the data carrier system of the present invention, in the data carrier system described above, the first tuning circuit includes the first transmission coil and a second tuning capacitor. The second tuning circuit is a series resonant circuit composed of a second tuning coil and a first tuning capacitor, and the first and second tuning circuits are different from each other. A circuit that is tuned to the lower one of the two frequencies and that has an adjustment capacitor connected in parallel to the second tuning circuit is connected to the first transmission coil of the first tuning circuit and the second tuning capacitor. It is characterized in that it is tuned to the higher one of the two different frequencies by intervening between them.
According to another aspect of the data carrier system of the present invention, in the data carrier system described above, the first tuning circuit is a series resonant circuit including a transmission coil and a first tuning capacitor. And the second tuning circuit is a parallel resonant circuit composed of a tuning coil and a second tuning capacitor, and the first and second tuning circuits are both of the lower of the two different frequencies. It is tuned to frequency, and the difference is obtained by connecting a circuit in which an adjustment coil is connected in series to the second tuning circuit in parallel to the transmission coil of the first tuning circuit or the first tuning capacitor. It is also characterized by tuning to the lower of the two frequencies.
According to another aspect of the data carrier system of the present invention, in the data carrier system described above, the first tuning circuit is a series resonant circuit including a transmission coil and a first tuning capacitor. The second tuning circuit is a parallel resonant circuit composed of a tuning coil and a second tuning capacitor, and the first and second tuning circuits are both higher ones of the two different frequencies. By connecting a circuit that is tuned to a frequency and in which an adjustment capacitor is connected in series to the second tuning circuit in parallel to the transmission coil of the first tuning circuit or the first tuning capacitor, It is characterized by being tuned to the lower of two different frequencies.
In order to achieve the above object, an interrogator for a data carrier system according to the present invention comprises a transmission coil and a transmission circuit connected to the transmission coil, and transmits a signal at two different frequencies. A plurality of reactance elements are connected in combination between the transmission coil and the transmission circuit, and a two-wave tuning circuit that tunes to both two different frequencies is connected.
In order to achieve the above object, an interrogator for a data carrier system according to the present invention includes a transmission coil and a transmission circuit connected thereto, and transmits a signal at two different frequencies. , Formed by connecting a first tuning capacitor to the transmission coil, and formed by connecting a second tuning capacitor to the tuning coil and a first tuning circuit for tuning to one of two different frequencies. A second tuning circuit that tunes to one of the two frequencies, and a reactance element that couples the first and second tuning circuits, the tuning circuit coupled by the reactance element being different from the other two frequencies To be in sync.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of a data carrier system using a data carrier according to an embodiment of the present invention. In FIG. 1, an interrogator 10 divides an oscillation circuit 11 that generates a basic signal of a carrier wave, and a basic signal from the oscillation circuit 11 with different division ratios to generate first and second carrier waves. Circuits 12 and 13, a selection circuit 15 that selects and outputs one carrier wave from the first and second carrier waves, an output amplifier 16, a first tuning circuit 17, and a second tuning circuit 18 are provided.
[0013]
The interrogator 10 further includes an internal processing circuit 19 that generates a transmission signal and a demodulation circuit 20 that processes signals received by the tuning circuits 17 and 18. The first tuning circuit 17 includes an antenna coil L1 and a tuning capacitor C1, and the second tuning circuit 18 includes a tuning coil L2 and a tuning capacitor C2.
[0014]
The first tuning circuit 17 and the second tuning circuit 18 are connected in parallel as shown in FIG. 1, but are connected via an adjusting capacitor C3 for both tuning circuits. In FIG. 1, the input of the demodulation circuit 20 is the tuning circuits 17 and 18, but a receiving coil may be provided separately.
[0015]
The transponder 30 includes a transmission / reception coil 31, a tuning capacitor 32 connected in parallel to the transmission / reception coil 31, a rectifier circuit 33, a demodulation circuit 34 that performs FSK demodulation, an internal processing circuit 35, a transmission modulation circuit 36, and a transmission load. A transistor 37, a voltage adjustment load transistor 38, a voltage detection circuit 40, and a voltage regulator circuit 41 are included.
[0016]
Like the general signal processing circuit, the internal processing circuit 35 includes a CPU 35a, a RAM 35b, a ROM 35C storing a program, an electrically rewritable EEPROM 35d, and an interface 35e.
[0017]
The oscillation circuit 11 generates a 4 MHz reference signal, for example. This reference signal is supplied to the first and second frequency dividers 12 and 13, and the signal (125 KHz) divided by 1/32 by the first frequency divider 12 and 1 by the second frequency divider 13. A signal divided by / 34 (117.6470588 KHz) is obtained.
[0018]
When the internal processing circuit 19 instructs transmission of data having a logical value “1”, the selection circuit 15 selects the output of the first frequency dividing circuit 12, and a 125 KHz signal is output via the output amplifier 16 to the tuning circuit 17. , Send to 18.
[0019]
On the other hand, when the internal processing circuit 19 instructs the transmission of the data of the logical value “0”, the selection circuit 15 selects the output of the second frequency dividing circuit 13 and sends a signal of 117.6470588 KHz through the output amplifier 16. To the tuning circuits 17 and 18.
[0020]
The first tuning circuit 17 is designed so that the tuning frequency is matched to 125 KHz by adjusting the inductance of the antenna coil L1 and the capacitance of the tuning capacitor C1. The second tuning circuit 18 is also designed to match the tuning frequency to a single 125 KHz by adjusting the inductance of the antenna coil L2 and the capacitance of the tuning capacitor C2.
[0021]
Then, with respect to the signal of 125 KHz, the entire circuit connecting the first tuning circuit 17 and the second tuning circuit 18 is also tuned to 125 KHz. That is, the impedance becomes large (ideally infinite).
[0022]
Here, when a signal of 117.76047088 KHz (hereinafter simply referred to as 117 KHz) is input to the first tuning circuit 17 where 125 KHz is tuned, the contribution to the total impedance of the capacitance of the LC parallel resonant circuit is Since the frequency becomes relatively low as the frequency becomes low, the first tuning circuit 17 appears to be “inductance L”. Similarly, the second tuning circuit 18 alone appears as “inductance L”.
[0023]
However, since the series circuit of the second tuning circuit 18 and the adjustment capacitor C3 is ((1 / ωC)> ωL), it appears as “capacitance C” as a whole. Accordingly, when switching to a signal of 117 KHz, the entire tuning circuit in which the first tuning circuit 17 and the second tuning circuit 18 are connected by the adjusting capacitor C3 is the “inductance L” of the first tuning circuit 17 and the second tuning circuit 17. Can be regarded as an LC tuning circuit of “capacitance C” of a series circuit of the tuning circuit 18 and the adjustment capacitor C3.
[0024]
In this embodiment, the adjustment capacitor C3 is adjusted so that the tuning frequency of the LC tuning circuit matches 1177.6470588 KHz, so that 125 KHz and 117 KHz aiming at two peaks as shown in FIG. Adjust to.
[0025]
In this adjustment, first, the inductance of the antenna coil L1 and the capacitance of the tuning capacitor C1 are adjusted so that the first tuning circuit 17 is tuned to 125 KHz alone. Similarly, the second tuning circuit 18 is adjusted to be tuned to 125 KHz alone.
[0026]
Next, a 117 KHz signal is input and the adjustment capacitor C3 is adjusted so that the other peak coincides with 117 KHz. When the other peak is higher than 117 KHz (FIG. 2A), the adjustment capacitor C3 is increased, and when it is lower than 117 KHz as shown in FIG. As shown in b), both peaks are drawn so as to coincide with 125 KHz and 117 KHz.
[0027]
Further, the balance between the peak values of both peaks can be adjusted to have the same peak value by setting the ratio of the tuning capacitors C1 and C2 of the first tuning circuit 17 and the second tuning circuit 18.
[0028]
Thus, in the first embodiment of the present invention, the transmission coil can be tuned to the transmission signal at any of the two frequencies of FSK, and a high peak can be obtained. Therefore, the transmission output is increased and sufficient power can be supplied to the responder 30. In this embodiment, the responder 30 transmits data by ASK modulation. Hereinafter, the operation of the responder 30 will be described.
[0029]
The tuning frequency of the tuning circuit composed of the transmission / reception coil 31 and the tuning capacitor 32 of the responder 30 is the center of two frequencies of 125 KHz and 1177.647088 KHz, that is, √ (root) (125 KHz × 117.6470588) = 121. It is set to 2678125 KHz. Accordingly, the transponder 30 can receive signals of substantially the same strength when receiving the logical value “1” and when receiving the logical value “0”.
[0030]
The electric power in the responder 30 is used by converting the carrier wave received by the tuning circuit including the transmission / reception coil 31 and the tuning capacitor 32 into a direct current by the diode 33a and the smoothing capacitor 33b of the rectifier circuit 33. A voltage regulator 41 is provided to further stabilize the voltage used in the internal processing circuit 35. The voltage detection circuit 40 detects the output voltage of the rectifier circuit 33.
[0031]
When data is transmitted from the responder 30 to the interrogator 10, data generated by the CPU 35a in the internal processing circuit 35 is transmitted to the modulation circuit 36 via the interface 35e, and is transmitted according to the output of the modulation circuit. The load transistor 37 is turned on / off. Then, the current flowing through the transmission / reception coil 31 changes, and the strength of electromagnetic coupling between the transmission / reception coil 31 and the antenna coil L1 changes.
[0032]
The demodulating circuit 20 of the interrogator 10 detects a change in the voltage generated at both ends of the antenna coil 17, specifically, a change in the amplitude of the 125 KHz signal output from the first frequency dividing circuit 12, and outputs from the responder 30. Demodulate the data. Actually, a band-pass filter performs demodulation operation on the 125 KHz signal output from the first frequency divider 12 by detecting changes in the amplitude and phase of the subband signal sent from the data carrier. .
[0033]
Next, the form of the 2nd Example of this invention is demonstrated. In the second embodiment, as shown in FIG. 3, two tuning circuits 50 and 51 and an adjustment capacitor C6 are also provided on the responder 30 side. The tuning circuit 50 includes an antenna coil L4 and a tuning capacitor C4, and the tuning circuit 51 includes a tuning coil L5 and a tuning capacitor C5. As shown in FIG. 3, a series circuit of a tuning circuit 51 and a regulating capacitor C6 is connected in parallel to the tuning circuit 50.
[0034]
The tuning circuits 50 and 51 are both tuned to 121 KHz, which is an intermediate frequency of the signal from the interrogator, and are connected to each other in parallel via the adjusting capacitor C6 to obtain the signal frequency from the responder 30 to the interrogator. It is also tuned to 62.5 KHz. Thus, the transmission efficiency is increased because the signals from both the interrogator and the responder are tuned. Incidentally, since the signal from the interrogator is tuned to an intermediate frequency, there is a concern that the transmission efficiency may be lowered. Generally, in the responder, the load on the tuning circuit is heavy and high. Is often not a problem.
[0035]
Next, a third embodiment of the present invention will be described. In the third embodiment, as shown in FIG. 4, the interrogator 10 is the same as that of the first embodiment. Although the responder 30 performs ASK modulation in the first and second embodiments, the responder 30 also performs data transmission by performing FSK modulation in the third embodiment. In FIG. 4, a modulation circuit 36 is an FSK modulation circuit having the same structure as the FSK modulation circuit of the interrogator.
[0036]
FIG. 5 lists modifications of the tuning circuit. FIG. 5A has a configuration in which two LC parallel circuits are connected by a coil L, and has a tuning characteristic as shown in FIG. FIG. 5B has a configuration in which two LC parallel circuits are connected by a capacitor C, and has tuning characteristics as shown in FIG.
[0037]
FIG. 5C has a configuration in which a parallel circuit of L2C2 is connected to a series circuit of L1C1 with a capacitor C, and has a tuning characteristic as shown in FIG. FIG. 5D has a configuration in which a parallel circuit of L2C2 is connected to a series circuit of L1C1 by a coil L, and has a tuning characteristic as shown in FIG.
[0038]
In FIG. 5E, a series circuit of two coils L1 and L2 and two capacitors C1 and C2 are connected in series, and a connection point between the coils L1 and L2 and a connection point between the capacitors C1 and C2 are connected by an adjustment capacitor C. It has a connected configuration and has tuning characteristics as shown in FIG.
[0039]
In FIG. 5 (f), a series circuit of two coils L1 and L2 and two capacitors C1 and C2 are connected in series, and the connection point between the coils L1 and L2 and the connection point between the capacitors C1 and C2 are connected by the adjustment coil L. It has a connected configuration and has tuning characteristics as shown in FIG. In FIG. 5 (g), two coils L1 and L2 and two capacitors C1 and C2 are connected as shown in the figure. It has a connected configuration and has tuning characteristics as shown in FIG.
[0040]
In FIG. 5 (h), two coils L1 and L2 and two capacitors C1 and C2 are connected as shown in the figure. It has a connected configuration and has tuning characteristics as shown in FIG. Thus, there are various configurations of the tuning circuit, and which configuration is used is a design matter.
[0041]
The present invention uses a technique that combines two tuning circuits that are tuned to the same frequency to form a two-wave tuning circuit with two peaks. By applying this technique, the present invention can be applied to other embodiments.
[0042]
As shown in FIG. 9, it can be applied to a system in which the transmission frequency and the reception frequency are different. The circuit configuration can be realized with the same configuration as the embodiment shown in FIG. The transmission method is FSK, and the interrogator tuning circuits 17 and 18 are centered at two frequencies of FSK modulation 125 KHz and 117.6470588 KHz, that is, root (125 KHz × 1177.6470588) = 121.2678125 KHz, one peak. Is set to have.
[0043]
Further, the tuning characteristic is adjusted so as to draw a gentle curve as compared with the first to third embodiments, and is set so as to correspond to both 125 KHz and 117 KHz. The tuning circuits 17 and 18 of the interrogator adjust the adjustment capacitor C3 so that the other peak is a sideband that is ASK modulated by the modulation circuit 36 of the responder and matches the frequency (62.5 KHz) of the received signal. Is done. Thereby, as viewed from the interrogator 10, it is possible to easily configure a system adapted to both transmission (FSK modulation) and reception (ASK modulation).
[0044]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a data carrier system and a data carrier interrogator that can obtain a high degree of coupling while performing FSK communication without requiring special switching.
Furthermore, according to the present invention, it is possible to provide a data carrier system and a data carrier interrogator that can obtain a high transmission output without requiring special switching when performing FSK communication.
Further, according to the present invention, as viewed from the interrogator, a system adapted to both transmission (FSK modulation) and reception (ASK modulation) can be easily configured.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a data carrier system according to a first embodiment of this invention.
FIG. 2 is a waveform diagram for explaining a tuning circuit adjustment method in the data carrier system of the first embodiment;
FIG. 3 is a block diagram illustrating a configuration of a data carrier system according to a second embodiment.
FIG. 4 is a block diagram illustrating a configuration of a data carrier system according to a third embodiment.
FIG. 5 is a circuit diagram illustrating a modification of the tuning circuit.
FIG. 6 is a waveform chart for explaining the operation of the data carrier system of the fourth embodiment.
FIG. 7 is a waveform diagram for explaining the operation of the data carrier system of the fourth embodiment;
FIG. 8 is a waveform diagram for explaining the operation of the data carrier system of the fourth embodiment;
FIG. 9 is a waveform diagram for explaining a tuning waveform of a system having different transmission frequency and reception frequency.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Interrogator 11 Oscillator 12 Divider 14 Divider 16 Output amplifier 17 First tuning circuit 18 Second tuning circuit 30 Transceiver 31 Transceiver coil 32 Tuning capacitor 33 Rectifier circuit 34 Demodulator circuit 35 Internal processing circuit 36 Credit modulation circuit

Claims (12)

A transmission station having a transmission coil and a transmission circuit connected thereto, transmitting a signal at two different frequencies, a reception coil receiving a magnetic field transmitted from the transmission station, and received by the reception coil In a data carrier system having a data carrier with a rectifier circuit for extracting power from a signal,
A data carrier system, wherein a plurality of reactance elements are connected in combination between the transmission coil and the transmission circuit, and a two-wave tuning circuit is tuned to both of the two different frequencies. A transmission station having a transmission coil and a transmission circuit connected thereto, transmitting a signal at two different frequencies, a reception coil receiving a magnetic field transmitted from the transmission station, and received by the reception coil In a data carrier system having a data carrier with a rectifier circuit that extracts power from a signal,
A first tuning circuit formed by connecting a first tuning capacitor to the transmission coil and tuned to one of the two different frequencies;
A second tuning circuit formed by connecting a second tuning capacitor to the tuning coil and tuned to one of the two different frequencies;
A reactance element that couples the first tuning circuit and the second tuning circuit is provided, and the tuning circuit coupled by the reactance element is tuned to the other of the two different frequencies. A data carrier system characterized by that. The data carrier system according to claim 2,
The first tuning circuit is a parallel resonant circuit including a first transmission coil and a first tuning capacitor,
The second tuning circuit is a parallel resonant circuit composed of a second tuning coil and a second tuning capacitor, and the first and second tuning circuits are both higher ones of the two different frequencies. Tuned to the frequency
A data carrier comprising a circuit in which an adjustment capacitor is connected in series to a second tuning circuit, connected in parallel to the first tuning circuit, and tuned to a lower one of the two different frequencies system. The data carrier system according to claim 2,
The first tuning circuit is a parallel resonant circuit including a first transmission coil and a first tuning capacitor,
The second tuning circuit is a parallel resonant circuit composed of a second tuning coil and a second tuning capacitor;
The first and second tuning circuits are both tuned to the lower of the two different frequencies,
A data carrier system characterized in that a circuit in which an adjustment coil is connected in series to a second tuning circuit is connected in parallel to the first tuning circuit and is tuned to the higher of the two different frequencies. The data carrier system according to claim 2,
The first tuning circuit is a series column resonance circuit composed of a first transmission coil and a second tuning capacitor;
The second tuning circuit is a series resonant circuit composed of a second tuning coil and a first tuning capacitor;
The first and second tuning circuits are both tuned to the higher one of the two different frequencies,
A data carrier system characterized in that a circuit in which an adjustment coil is connected in parallel to a second tuning circuit is connected in series to the first tuning circuit and is tuned to the lower of the two different frequencies. . The data carrier system according to claim 2,
The first tuning circuit is a series resonant circuit composed of a first transmission coil and a second tuning capacitor;
The second tuning circuit is a series resonant circuit composed of a second tuning coil and a first tuning capacitor;
The first and second tuning circuits are both tuned to the lower of the two different frequencies,
A data carrier system characterized in that a circuit in which an adjustment capacitor is connected in parallel to a second tuning circuit is connected in series to the first tuning circuit and is tuned to the higher one of the two different frequencies . The data carrier system according to claim 2,
The first tuning circuit is a parallel resonant circuit composed of a first transmission coil and a second tuning capacitor;
The second tuning circuit is a series resonant circuit composed of a second tuning coil and a first tuning capacitor;
The first and second tuning circuits are both tuned to the higher one of the two different frequencies,
The two different frequencies are obtained by interrupting and connecting a circuit in which an adjustment coil is connected in parallel to the second tuning circuit between the first transmission coil of the first tuning circuit and the first tuning capacitor. A data carrier system characterized by being tuned to a lower frequency. The data carrier system according to claim 2,
The first tuning circuit is a parallel resonant circuit composed of the first transmission coil and a second tuning capacitor;
The second tuning circuit is a series resonant circuit composed of a second tuning coil and a first tuning capacitor;
The first and second tuning circuits are both tuned to the lower of the two different frequencies,
A circuit in which an adjustment capacitor is connected in parallel to the second tuning circuit is connected between the first transmission coil of the first tuning circuit and the second tuning capacitor so as to have the two different frequencies. A data carrier system that is tuned to a higher frequency. The data carrier system according to claim 2,
The first tuning circuit is a series resonant circuit including a transmission coil and a first tuning capacitor;
The second tuning circuit is a parallel resonant circuit composed of a tuning coil and a second tuning capacitor;
The first and second tuning circuits are both tuned to the lower of the two different frequencies,
By connecting a circuit in which an adjustment coil is connected in series to the second tuning circuit in parallel to the transmission coil of the first tuning circuit or the first tuning capacitor, the lower of the two different frequencies is selected. A data carrier system that is also tuned to frequency. The data carrier system according to claim 2,
The first tuning circuit is a series resonant circuit including a transmission coil and a first tuning capacitor;
The second tuning circuit is a parallel resonant circuit composed of a tuning coil and a second tuning capacitor;
The first and second tuning circuits are both tuned to the higher one of the two different frequencies,
By connecting a circuit in which an adjustment capacitor is connected in series to the second tuning circuit in parallel to the transmission coil of the first tuning circuit or the first tuning capacitor, the lower of the two different frequencies A data carrier system that is also tuned to the frequency of. In an interrogator for a data carrier system that includes a transmission coil and a transmission circuit connected to the transmission coil and transmits signals at two different frequencies,
An interrogator for a data carrier system, wherein a plurality of reactance elements are connected in combination between the transmission coil and the transmission circuit, and a two-wave tuning circuit for tuning to both of the two different frequencies is connected. In an interrogator for a data carrier system that includes a transmission coil and a transmission circuit connected to the transmission coil and transmits signals at two different frequencies,
A first tuning circuit formed by connecting a first tuning capacitor to the transmission coil and tuned to one of the two different frequencies;
A second tuning circuit formed by connecting a second tuning capacitor to the tuning coil and tuned to one of the two different frequencies;
And a reactance element that couples the first and second tuning circuits, and the tuning circuit coupled by the reactance element is tuned to the other of the two different frequencies. Interrogator for carrier system.

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