JP2885012B2 - Mobile object identification system and its modulation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly uses an electromagnetic wave of UHF, microwave band or the like to write data to a transponder attached to a mobile body by using a reflected wave thereof, and to transmit data from the transponder. The present invention relates to a mobile object identification system that performs identification of a mobile object, data communication, and the like by reading, and a modulation method thereof.

[0002]

2. Description of the Related Art Recently, a system has been put to practical use, in which a mobile body is identified by performing modulation at the time of reflection using mainly radio waves in a microwave band. Further, there are attempts to selectively perform communication by applying spread spectrum to the electromagnetic waves at that time.

[0003] For example, a configuration described in Japanese Patent Application Laid-Open No. 2-8770 is known. Hereinafter, a conventional moving object identification system using reflected waves in the microwave band will be briefly described with reference to FIG.

In FIG. 5, an interrogator 1 continuously emits, from a transmitting antenna 52, an interrogating signal X obtained by modulating an oscillation signal of an oscillator 50 by a modulator 51 with arbitrary transmission data. In the communication area of this interrogation signal X, the transponder 8
Is received, the transponder 8 detects the presence of the interrogation signal X received by the receiving antenna 53, and transmits the interrogation signal X to the spectrum according to the identification code held in the identification code memory 54 of the transponder 8 itself. Spread spectrum modulation is performed by the spread modulator 55 and re-emitted from the transmission antenna 56. The interrogator 1 has a memory table 57 which stores all the identification codes of the transponders 8 which need to be identified, and selects any one of these identification codes. , The response signal Y received by the receiving antenna 58 is demodulated by the spread spectrum demodulator
Get.

[0005]

However, in the configuration described above, the means (spread spectrum modulator 55) for performing spread modulation on the transponder 8, which requires particularly small size and low power consumption, is used.
In addition, the interrogator 1 needs to synchronize the interrogator 1 and the transponder 8, and the interrogator 1 and the transponder 8 both require a large circuit scale for identifying a moving object. Had. Further, only reading of data from the transponder 8 and writing of data to the transponder 8 are not assumed.

The present invention has been made to solve the above-mentioned problems, and a relatively small-scale mobile object identification system capable of obtaining a wide communication range even when a plurality of interrogators and radio wave reflecting objects are present around a transponder. An object of the present invention is to realize a circuit configuration and to enable not only reading data from a transponder but also writing data to the transponder.

[0007]

Means for Solving the Problems To achieve the above object, a technical solution of the present invention is to provide an interrogator with a carrier spread signal obtained by spreading a carrier with a pseudo-noise sequence code, or the carrier spread signal having a further amplitude. Interrogator-side interrogation signal generating means for transmitting a shift-modulated signal, interrogator-side transmitting antenna for transmitting an output signal from the interrogator-side interrogation signal generating means, and interrogator side for receiving a reflected wave from the transponder A receiving antenna; an interrogator-side mixing means for mixing a signal from the interrogator-side receiving antenna with a signal from the interrogator-side signal generating means; and an interrogator for demodulating from an output signal of the interrogator-side mixing means. -Side data demodulation means, a transponder-side receiving antenna for receiving an interrogator-side output signal transmitted from the interrogator-side transmitting antenna, and an interrogator-side output received by the transponder-side receiving antenna Transponder-side electromagnetic wave detecting means for detecting a signal, transponder-side data storage means storing data to be modulated, and determining the output voltage of the transponder-side electromagnetic wave detecting means, and controlling the operation of the transponder. Transponder-side voltage determination means for performing, transponder-side data modulation means for modulating an interrogator-side output signal from the transponder-side receiving antenna based on data in the transponder-side data storage means, and the transponder-side data This is a mobile object identification system provided with a transponder-side transmission antenna for transmitting a response signal to the interrogator based on the modulation of the modulation means.

In addition to transmitting an electromagnetic wave from the interrogator, receiving a reflected wave from the transponder and demodulating the data, the transponder performs modulation using reflection of the electromagnetic wave. In the first case of reading the information, the interrogator-side interrogation signal generator sends out a carrier spread signal obtained by spreading the carrier with a pseudo-noise sequence code, and responds to the data stored in the responder-side data storage. In the second case, amplitude shift modulation is performed by the transponder-side detection / data modulation means, and information is sent when changing the operation mode of the transponder or writing data to the data storage means. The interrogator-side interrogation signal generating means transmits a signal obtained by further amplitude-shifting the carrier spread signal, and outputs a detection output obtained by the transponder-side detection / data modulation means. It is a modulation method of a mobile identification system using No..

[0009]

According to the present invention, even if there are a plurality of interrogators in the first place, signals from other interrogators can be demodulated in the demodulation process by using pseudo noise sequence signal generation means of different sequences. Since there is no correlation and only a correlated signal is demodulated, the operation can be performed without any mutual influence.

Secondly, the spread modulation signal generating means can be shared for transmission and reception, and the signal input from the interrogator to the interrogator via the transponder has a short propagation distance of several meters, so that the spread spectrum signal or the like is not used. The deviation of the synchronization of the spread modulation signal is reduced, and a simple configuration can be achieved because a special synchronization circuit is not required.

Third, the carrier spread signal is further amplitude-shift-modulated so that not only data can be read from the transponder but also data can be written to the transponder.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a circuit diagram in the case where the modulation method of the moving object identification system according to the first embodiment of the present invention is employed.

In FIG. 1, 1 is an interrogator, and 8 is a responder. In the interrogator 1, reference numeral 2 denotes interrogation signal generation means for generating an interrogation signal. The interrogation signal generation means 2 is an amplitude shift modulation means 4 for further amplitude-shift modulating a carrier spread signal 3 obtained by spreading a carrier with a pseudo noise sequence code. And switching means 5 for switching the output between the carrier spread signal 3 and the amplitude-shift-modulated signal. Reference numeral 6 denotes a transmitting antenna for transmitting a signal from the switching means 5 to the transponder 6 as an interrogation signal 7. Reference numeral 10 denotes a receiving antenna for receiving a reflected wave including the response signal 9 reflected by the transponder 8, and reference numeral 11 denotes a reception demodulation for frequency-converting a signal from the interrogation signal generating means 2 by a signal using local oscillation and performing data demodulation. Means 13 is a communication state determining means for transmitting a switching signal 14 to the switching means 5 using the decoding signal 12 obtained by the receiving / demodulating means 11.

On the other hand, in the transponder 8, reference numeral 17 denotes a detection / data modulating means for detecting the electromagnetic wave obtained by the transponder antenna 15 and reflecting the electromagnetic wave according to the data held in the data storage means 16 when the electromagnetic wave is reflected. Modulation
The spread modulation signal is reflected from the transponder antenna 15 as a response signal 9.

The operation of the above configuration will be described below. First, in the first case of reading information from the transponder 8, the interrogator 1 uses, for example, spread spectrum modulation or the like.
A spread-modulated signal capable of generating a plurality of pseudo-noise sequence signals is emitted by the interrogation signal generating means 2, that is, a carrier spread signal 3 obtained by spreading and modulating a carrier signal as the interrogation signal 7 from the transmission antenna 6 via the switching means 5. I do.

On the other hand, in the second case of sending information to change the operation mode of the transponder 8 or to write data in the data storage means 16, the interrogation signal generation means 2, ie, the carrier spread signal 3 is further subjected to amplitude shift modulation by means of amplitude shift modulation means 4, and the signal is transmitted from a transmission antenna 6 via a switching means 5 to an interrogation signal 7.
Fire as

That is, the switching means 5 switches between the first case of reading information from the transponder 8 and the second case of sending information to the transponder.

When the transponder 8 enters the communication area of the two interrogation signals 7 output from the interrogator 1, the transponder 8 receives the signal via the transponder antenna 15 and performs detection. Alternatively, according to the data held in the data storage unit 16, the interrogation signal 7 is converted to the detection / data modulation unit 17.
In this manner, a data-modulated spread-modulated signal is obtained by performing modulation in a form such as amplitude shift modulation by changing a reflection condition by, for example, reflection or termination, and the signal is reflected from the transponder antenna 15 as a response signal 9. I do.

Since the propagation distance assumed in the mobile object identification system is as short as several meters, the synchronization deviation of the spread modulation signal is on the order of 10 ^-8 seconds, and does not cause much problem unless the spreading rate is high. In interrogator 1,
The signal from the spread modulation signal generation means 2 can be shared for transmission and reception, and the response signal 9 received by the reception antenna 10 is frequency-converted by the reception demodulation means 11, and decoding is performed from the decoding signal 12 obtained. And, for example, in the interrogator,
Although the end of the data is known in the transponder, the end of the communication data between the interrogator and the transponder has a data format of several bits for judging the end of the communication data. The switching means 5 is switched by the switching signal 14, and the interrogation signal 7 from the interrogator 1 is determined depending on whether the communication is reading or writing of information.
To change.

In the above description, the transmitting antenna 6 and the receiving antenna 10 of the interrogator 1 have been described as being configured separately. However, the transmitting and receiving signals may be separated by using an isolator in common. Further, the transponder antenna 15 of the transponder 8 is shared, and the transponder antenna 15 is used for both reception and reflection. However, the transponder antennas 15 may be separately provided for reception and emission of reflected radio waves, respectively. .

Further, instead of the amplitude shift modulation by the detection / data modulation means 17 of the transponder 8, subcarrier amplitude shift modulation or phase shift modulation may be used.

When transmitting information to the transponder 8, instead of transmitting a signal obtained by further performing amplitude shift modulation on the carrier spread signal 3 from the interrogation signal generating means 2, the carrier signal which is not spread is subjected to amplitude shift modulation. A signal may be sent.

As is clear from the above description, according to the present embodiment, even if there are a plurality of interrogators, the interrogator having the interrogation signal generating means having the pseudo noise sequence signals of different sequences is used. The signals from other interrogators become uncorrelated during the demodulation process, and only the correlated signals are demodulated, so that they can be operated without any mutual influence.

Further, since the spread modulation signal can be shared for transmission and reception, and complicated synchronization is not required, a simple configuration can be realized.

Further, in the communication between the interrogator and the transponder, even in the state where the spread modulation is performed, not only the data of the transponder but also the data including the control data can be sent to the transponder and the data can be written. .

Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. FIG. 2 shows a second embodiment of the present invention.
FIG. 3 is a circuit diagram of a transponder in a case where the modulation method of the mobile object identification system according to the embodiment is adopted, and FIG. 3 is a time series diagram of communication between the interrogator and the transponder in that case.

FIG. 2 is different from the configuration of FIG.
In the transponder 8, instead of the detection / data modulation means 17, an electromagnetic wave detection means 20, a data modulation means 21, a voltage determination means 22 for determining the output voltage of the electromagnetic wave detection means 20,
And an operation mode switching means 23 for switching an operation mode between a detection mode and a modulation mode.

The time-series diagram of FIG. 3 shows a to f shown in FIG.
Is a schematic representation of the operation waveform signal at the portion (1). Particularly, the waveforms of the high frequency signals a and f are not always accurate.

The operation of the above configuration will be described below. In the second embodiment, the operation of the transponder 8 will be mainly described.

The transponder 8 first operates in the detection mode (d in FIG. 3).
Is low level), and the presence of the interrogator signal 15 (FIG. 3A) received by the transponder antenna 15 when the transponder 8 enters the communication area of the interrogation signal 7 is detected by electromagnetic wave detection. The detection is performed by the means 20 (FIG. 3B), the determination is performed by the voltage determination means 22 (FIG. 3C), and the modulation mode (high level of FIG. 3D) is set by the operation mode switching means 23 (FIG. 3D).
1). The data stored in the data storage means 16 (FIG. 3
In accordance with e), the interrogation signal 7 is modulated by the data modulating means 21 in a format such as amplitude shift modulation by changing a reflection condition by, for example, reflecting or terminating the data, and a data-modulated spread modulation signal ( 3 is obtained and reflected as the response signal 9. When a series of data is completed, the mode is switched to the detection mode by the operation mode switching means 23 (FIG. 3).
D2). In the interrogator 1, the response signal 9 is demodulated, the end of a series of data is judged by the communication state judging means 13 of the interrogator 1, and the spread-modulated signal is further subjected to amplitude shift modulation to store the data. The data to be written into the means 16 or the interrogation signal 7 for changing the operation mode of the transponder 8 is transmitted (between d2 and d3 in FIG. 3). This signal is detected and determined by the transponder 8 in the detection mode, and the write data is processed. The end of the communication data between the interrogator 1 and the transponder 8 has a data format of several bits for judging the end of the communication data. The mode is switched to (d3 in FIG. 3). In the transponder 8, for example, modulation is performed in a form such as amplitude shift modulation by changing a reflection condition by reflection or termination to obtain a data-modulated spread modulation signal, which is reflected as a response signal 9, and a series of data is obtained. Upon completion, the mode is switched to the detection mode (d4 in FIG. 3).

The interrogator 1 demodulates the response signal 9 and determines the end of a series of communication data. Then, the interrogator 1 returns to the state of emitting the interrogation signal 7 obtained by spreading and modulating the carrier signal (from d4 in FIG. 3). ).

In the above description, the case where communication is read, write, and read has been described, but it is apparent that the present invention is not limited to this case.

The output voltage of the electromagnetic wave detecting means 20 is judged by the voltage judging means 22 and the contents of the data storing means 16 are rewritten by writing.
Based on this data, the data from the transponder antenna 15 can be read out by modulating the signal from the transponder antenna 15 by the data modulating means 21, and the data written into the transponder from the interrogator can also be confirmed.

As is clear from the above description, according to the present embodiment, even if a plurality of interrogators exist, they can be operated without any mutual influence, and the spread modulation signal generating means is shared for transmission and reception. And a simple configuration because no complicated synchronization is required. In addition, in the communication between the interrogator and the transponder, even when the spread modulation is performed, the detection mode and the modulation mode are used. , Data can be read and written efficiently from the transponder.

Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 is a circuit diagram of a moving object identification system according to the third embodiment of the present invention.

4 differs from the circuit diagrams of FIGS. 1 and 2 in that an oscillator 40 for producing a carrier signal and a spread signal for spreading with a pseudo noise sequence code are provided on the interrogator 1 side. Means 41, a first mixer 42 for mixing the outputs of the oscillator 40 and the spread signal generating means 41, a transmitting and receiving antenna 43 sharing an antenna, an isolator 44 for separating and outputting or supplying a transmitting and receiving signal, and separation by the isolator 44 Second mixer 4 for obtaining an output obtained by mixing the received signal and the signal from interrogation signal generating means 2
5, a data demodulating means 46 for demodulating the output signal of the mixer 45, and a data decoding means 47 for decoding data from the output decoding signal 12; 13 is used as an input control signal, and the transponder 8 is connected to the data modulating means 21 and the electromagnetic wave detecting means 20 in series. Note that 49a and 49b are amplifiers.

The differences between the above-described configuration and the first and second embodiments will be described below in order.

First, the operation of the interrogator 1 different from that of the first and second embodiments differs from the operation of the configuration of the interrogation signal generating means 2 and the data demodulation after the second mixer 45 of the interrogator. This is an operation in which a means 46 and a data decoding means 47 are provided, and decoded data 48 output from the data decoding means 47 is used as an input signal of the communication state determination means 13. This is because it is better to change which stage of the received data is used as the input signal of the communication state determining means 13 depending on the modulation method of the transponder. For example, in the case of amplitude shift modulation, a signal from the data demodulation unit 46 is also possible, and in the case of subcarrier amplitude shift modulation or phase shift modulation, a signal from the data decoding unit 47 is more preferable.

Next, regarding the antenna of the interrogator 1, the output signal from the interrogation signal generating means 2 is transmitted from the transmitting / receiving antenna 43 through the amplifier 49a and the isolator 44, and the reflected wave from the transponder 8 is transmitted to the transmitting / receiving antenna 43. The signal received at (1) is supplied separately to the receiving section (demodulation / combination section) through the isolator 44 and the amplifier 49b, and the antenna is shared. When configuring the mobile object identification system, the transmitting antenna and the receiving antenna of the interrogator 1 need to have a gain of about 10 dBi.
Sharing this is significant in terms of small size and low cost.

On the other hand, with respect to the method of connecting the electromagnetic wave detecting means 20 and the data modulating means 21 with respect to the transponder 8, in the second embodiment, only one of the transponders is arranged in parallel with the transponder antenna 15 depending on the operation mode of the transponder 8. Although the description has been given assuming that the transponder is operated, when the modulation method of the transponder is the amplitude shift modulation or the subcarrier amplitude shift modulation, the electromagnetic wave detection means 20 is connected next to the data modulation means 21 as in this embodiment, When the modulation is not performed, the high-frequency signal from the transponder antenna 15 is passed through the data modulating means 21 as it is and supplied to the electromagnetic wave detecting means 20. On the other hand, when the modulation is performed, the electromagnetic wave detecting means 20 is modulated. It can be used as a load when terminating, or it can be operated in series with a load before the electromagnetic wave detection means 20 or in parallel as both. It may be in the form to be. Therefore, the operation mode switching means 23 is not always necessary.

The output voltage of the electromagnetic wave detecting means 20 is
It can also be used as the power supply voltage of the transponder 8, and the output voltage of the electromagnetic wave detection means 20 is determined by the voltage determination means 22, and the power supply of the circuit such as the data modulation means 21 of the transponder 8 is cut off. It is also possible to reduce the power consumption of the transponder 8 when it is outside the range of the communication area.

As is clear from the above description, according to the present embodiment, even if a plurality of interrogators exist, they can be operated without any influence on each other, and the antenna and the spread modulation signal generating means can transmit and receive signals. Since it can be shared and does not require complicated synchronization, it can have a simple configuration. Further, in the communication between the interrogator and the transponder, even if the spread modulation is performed, the detection mode and the modulation mode can be used. By switching the data, it is possible to efficiently read and write the data of the transponder, and to reduce the power consumption of the transponder outside the communication area.

[0043]

As described above, according to the present invention, even when a plurality of interrogators are present and an object reflecting electromagnetic waves is present, there is no influence on each other. It is also possible to efficiently write data to the device, wireless data communication with reflected electromagnetic waves is possible in a wide communication area and communication conditions, and although the spread spectrum is used, the interrogator and transponder have a simple configuration. And the transponder can be operated with low power consumption.

As described above, the present invention has a great industrial effect on expanding the communication range and conditions, simplifying the circuit, reducing the cost, and the like.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a mobile object identification system when a modulation method of a mobile object identification system according to a first embodiment of the present invention is employed.

FIG. 2 is a circuit diagram of a transponder which is a main part when a modulation method of a mobile object identification system according to a second embodiment of the present invention is employed.

FIG. 3 is a time series diagram of communication between an interrogator and a transponder in a second embodiment of the present invention.

FIG. 4 is a circuit diagram of a moving object identification system according to a third embodiment of the present invention.

FIG. 5 is a circuit diagram of a configuration of a conventional moving object identification system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Interrogator 2 Interrogation signal generation means 4 Amplitude shift modulation means 5 Switching means 6 Transmission antenna 8 Transponder 10 Receiving antenna 11 Reception demodulation means 13 Communication state judgment means 15 Transponder antenna 16 Data storage means 17 Detection / data modulation means 20 Electromagnetic wave Detecting means 21 data modulating means 22 voltage determining means 23 operation mode switching means 43 transmitting / receiving antenna 45 mixing means 46 data demodulating means

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-140685 (JP, A) JP-A-64-37128 (JP, A) JP-A-63-144280 (JP, A) JP-A-63-144280 222283 (JP, A) JP-A-63-279621 (JP, A) JP-A-1-96784 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01S 7/00-7 / 42 G01S 13/00-13/95

Claims (17)

(57) [Claims] An interrogator uses a pseudo-noise sequence code for a carrier.
The spread carrier spread signal, or the carrier spread signal
Interrogator interrogator that sends out a signal with further amplitude shift modulation
Signal generation means, and the interrogator-side interrogation signal generation means
Interrogator side transmitting antenna for transmitting output signal and responder
An interrogator-side receiving antenna for receiving reflected waves from the
Signal from interrogator side receiving antenna and generation of interrogator side signal
Interrogator-side mixing means for mixing signals from the means,
Interrogator side demodulating from the output signal of the interrogator side mixing means
Data demodulating means, and transmitting the interrogator side to the transponder.
When receiving the interrogator output signal sent from the antenna
Both for a transponder that sends a response signal to the interrogator
Antenna and transponder that stores data to be modulated
Data storage means, and an electric power obtained by the transponder antenna.
While detecting the magnetic wave, the transponder-side data storage means
Modulates based on the data and converts the signal to the transponder
With transponder-side detection and data modulation means for outputting to the antenna
A moving object identification system. 2. An interrogator-side interrogation signal generating means for transmitting, to an interrogator, a carrier spread signal obtained by spreading a carrier with a pseudo-noise sequence code or a signal obtained by further amplitude-shift modulating the carrier spread signal; An interrogator-side transmitting antenna for transmitting an output signal from the interrogator signal generating means, an interrogator-side receiving antenna for receiving a reflected wave from the transponder, a signal from the interrogator-side receiving antenna, and the interrogator-side signal generation Interrogator-side mixing means for mixing the signal from the means, and interrogator-side data demodulation means for demodulating from the output signal of the interrogator-side mixing means , to the transponder, from the interrogator-side transmission antenna to the receiving the transmission has been interrogator side output signal
Both for a transponder that sends a response signal to the interrogator
Antenna , transponder-side electromagnetic wave detection means for detecting the interrogator-side output signal received by the transponder antenna, transponder-side data storage means storing data to be modulated,
A transponder-side voltage determination unit that determines an output voltage of the transponder-side electromagnetic wave detection unit and controls an operation of the transponder;
Signal line iso modulation to the interrogator side output signal from antenna
Transponder-side data modulation for outputting to the transponder antenna
Mobile object identification system comprising: 3. The output voltage of the transponder-side electromagnetic wave detection means is determined by the transponder-side voltage determination means, and the content of the transponder-side data storage means is rewritten. response by the responder side data modulator
3. The moving object identification system according to claim 2, wherein the signal from the answering device antenna is modulated. Wherein determining the response-side voltage determining means for the output voltage of the responder side electromagnetic wave detecting means, and performing power off response-side data modulator according to claim 2 mobile identification according system. 5. The moving object identification system according to claim 2, wherein an output voltage of the transponder-side electromagnetic detection means is used as a power supply voltage of the transponder. 6. A transponder antenna for receiving and transmitting.
6. The antenna according to claim 1, wherein the antenna is a separate antenna.
The mobile communication system according to any one of the above. 7. An interrogator transmits an electromagnetic wave, receives a reflected wave from a transponder, demodulates the data, and performs a modulation using reflection of the electromagnetic wave on the transponder. In the first case of reading information,
From the interrogator-side interrogation signal generating means, a carrier spread signal is generated by spreading the carrier with a pseudo-noise sequence code, and according to the data stored in the transponder-side data storage means, the transponder-side detection / data modulation means Perform amplitude shift modulation,
Further, in the second case of changing the operation mode of the transponder or sending information when writing data to the data storage means, the interrogator-side interrogation signal generation means further increases the amplitude of the carrier spread signal. A modulation method for a mobile object identification system that transmits a shift-modulated signal and uses a detection output signal obtained by the transponder-side detection / data modulation unit. 8. The modulation method for a mobile object identification system according to claim 7, wherein subcarrier amplitude shift modulation is used instead of amplitude shift modulation by the transponder detection / data modulation means. 9. The modulation method for a moving object identification system according to claim 7 , wherein a phase shift modulation is used instead of the amplitude shift modulation by the transponder detection / data modulation means. 10. In the second case of sending information to the transponder, instead of sending out a signal obtained by further amplitude-shifting the carrier spread signal from the interrogator-side interrogation signal generating means, the interrogator-side interrogation signal generating means is provided. 8. A modulation method for a mobile object identification system according to claim 7, wherein a signal obtained by subjecting a carrier signal to amplitude shift modulation is transmitted from the control unit. 11. The modulation of the mobile object identification system according to claim 7, wherein the modulation has a data format of several bits for judging the end of the communication data from the interrogator or the end of the communication data from the transponder. method. 12. A transponder-side data modulation means and a transponder-side electromagnetic wave detection means as transponder-side detection / data modulation means, and a transponder-side voltage determination means for judging an output voltage of the transponder-side electromagnetic wave detection means. 8. The modulation of the moving object identification system according to claim 7, wherein the operation mode of the transponder is changed or data is written in the data storage means in accordance with an output signal of the transponder-side voltage determination means. method. 13. A transponder connected to a transponder-side electromagnetic wave detecting means when the transponder enters the communication area before the transponder enters the communication area of the interrogator. The mode is switched from the detection mode to the modulation mode by the output signal of the responder-side data storage means, modulation by the transponder-side data modulation means in accordance with the data of the transponder-side data storage means is started, and a series of When the end of the data, the mode is switched to the detection mode. On the other hand, when the interrogator determines the end of the series of data by the interrogator-side communication state determination unit and sends information from the interrogator, the interrogator-side electromagnetic wave detection unit. 13. The moving object identification system according to claim 12, wherein writing is performed in said transponder-side data storage means in accordance with an output signal of said transponder-side voltage determination means connected to said transponder. The modulation method of the system. 14. Control of the operation mode of the transponder or writing of data to the transponder-side data storage means in accordance with the output signal of the transponder-side voltage judgment means, and in accordance with the output signal of the transponder-side voltage judgment means. 14. The modulation method according to claim 13, wherein the mode is switched to a modulation mode when the end of the data is determined. 15. An interrogator receiving and demodulating means for receiving and demodulating a reflected signal from the transponder-side detection / data modulation means, and an interrogator using an output signal of the interrogator-side reception / demodulation means. And an interrogator-side communication state determining means for determining a communication state between the responder and a first case of reading information from the responder by an output signal of the interrogator-side communication state determining means; 8. The modulation system according to claim 7, further comprising switching means for switching between a second case of sending information to the transponder and the second case. 16. The interrogator-side communication state determining means determines the end of a series of data from the transponder as a part of data communication from the output signal of the interrogator-side receiving and demodulating means. When transmitting information, an output signal for switching a signal obtained by further amplitude-shifting the carrier spread signal from the interrogator-side interrogation signal generating means from the interrogator is supplied to the switching means. 16. The modulation method of the mobile object identification system according to 15. 17. The interrogator-side communication state determining means determines the end of data communication between the interrogator and the transponder from the output signal of the interrogator-side receiving and demodulating means. 16. An output signal for switching to send a signal is supplied to a switching means.
The modulation method of the moving object identification system described in the above.