JPH05297131A - Moving body distinguishing device - Google Patents

Abstract

PURPOSE:To make a transponder of light and small construction, suppress the cost therefor, and lessen its power consumption by incorporating the spread modulation/demodulation system in communications of the transponder with an inquirer. CONSTITUTION:The carrier wave generated by a carrier wave transmitter 11 of an inquirer Q is subjected to spread spectrum modulation by a spread modulator 12 with spread codes prepared by a spread code generator 13, and wide band signals are released from an antenna 16. A transponder A having received signal performs modulation for signal received by a symbol modulator 17 with the data stored in a memory 18 and re-radiates the modulated signals from the antenna 16. The inquirer Q having received the re-radiated wide band signal with the antenna 16 performs spread demodulation using a spread demodulator 15 by the same spread code series as used at modulating and turns the spread spectrum wide-band signals into narrow band. The data held by the transponder A can be read by demodulating these signals with a code demodulator 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reads the identification number of a transponder from a interrogator using a non-contact communication means such as radio waves from a transponder attached to a moving body, or transmits data to the transponder. The present invention relates to a moving body identification device for writing, and is used, for example, for automation of a production line.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram of a conventional moving body identifying apparatus. In the figure, Q is an interrogator and A is a responder. In this conventional example, when reading the data held by the transponder A, first, a radio wave for reading is radiated from the carrier wave oscillator 21 of the interrogator Q through the antenna 24.
The transponder A which receives this radio wave by the antenna 24 modulates this radio wave by the code modulator 25 with the data stored in the memory 26, and radiates it again by the antenna 24. The interrogator Q receives the radio wave re-radiated by the responder A by the antenna 24, detects the signal by the mixer 23, and demodulates it by the code demodulator 22 to read the data of the responder A. ..

However, in a moving body identifying apparatus used for automation of a production line, it is often the case that a plurality of interrogators Q and responders A are installed near each other and used, and in such a state, it is intended to communicate. There was a problem that normal communication could not be performed due to the interference of radio waves radiated from other interrogators other than the interrogator present.

Therefore, conventionally, as shown in FIG. 3, a non-contact type moving body identification apparatus using a spread code modulation / demodulation method for communication has been proposed (see Japanese Patent Laid-Open No. 3-181235).
In this conventional example, first, the carrier wave oscillated by the carrier wave oscillator 38 of the responder A is modulated by the code modulator 37 by the data stored in the memory 36, and then the signal is spread by the spread code generator 33. Spread spectrum modulation is performed by the spread modulator 35 using the spread code generated in the above step, and the spectrum is radiated from the antenna 34. The interrogator Q receives the signal radiated from the responder A by the antenna 34, demodulates it using the spread code generator 33 and the spread demodulator 32, and further, the spread demodulated signal is code demodulator 31. The data of the transponder A is read by demodulation.

[0005]

In the conventional example shown in FIG. 2, noise from other equipment and electric field strength of the radio wave radiated by the interrogator Q installed near the radio wave re-radiated from the responder A. In some cases, there is a problem that normal communication cannot be performed.

Further, in the conventional example shown in FIG. 3, when the noise radiated from another device is received by the interrogator Q, the noise is diffused by the spread demodulator 32 and the influence on the communication is reduced. However, since the spreading code generator 33 that generates the same code sequence is used for the signals radiated from other transponders A in the vicinity, the influence cannot be reduced, and transmission due to interference is not possible. You cannot prevent mistakes. Further, in this conventional example, the carrier oscillator 3
8. Since the spread code generator 33 and the spread modulator 35 are provided in the responder A, there is a problem that the responder A becomes large and the battery life is shortened due to an increase in current consumption.

The present invention has been made in view of the above points, and an object of the present invention is to provide a transponder attached to a moving body and an interrogator for communicating with the transponder in a non-contact manner. In the mobile identification device consisting of, by using the spread modulation / demodulation method for communication between the interrogator and the responder, it is possible to reduce the influence of interference waves from other interrogators in the vicinity and noise from other devices, and By arranging the circuit required for modulation / demodulation on the interrogator side, it is possible to reduce the size and weight of the transponder, reduce the cost, and reduce the power consumption.

[0008]

According to the present invention, in order to solve the above-mentioned problems, as shown in FIG. 1, a transponder A attached to a moving body and a non-contact with the transponder A are provided. In the mobile unit identification device including the interrogator Q that communicates with the interrogator Q, the interrogator Q has a spread code modulation unit in the interrogation signal transmission unit and the interrogator Q has the spread code demodulation unit in the response signal reception unit. It is characterized by.

[0009]

In the mobile unit identifying apparatus of the present invention, the interrogation signal transmitting section of the interrogator is provided with the spread code modulation means, and the response signal receiving section of the interrogator is provided with the spread code demodulation means.
Even if noise from other devices is received by the interrogator,
The received noise is spread over a wide frequency band by the spreading demodulator 15, so that it does not affect the operation of the code demodulator 14 in the subsequent stage. Further, since the spreading code used is different for the interference wave from another interrogator installed nearby, the band of the interference wave is not spread even if it passes through the spread demodulator 15 of the receiving section. Code demodulator 1 in the latter stage
4 does not affect the operation.

[0010]

1 is a block circuit diagram of an embodiment of a moving body identifying apparatus of the present invention. In this device, first, a carrier wave is generated from a carrier wave oscillator 11 of an interrogator Q, the carrier wave is spread-spectrum modulated by a spread modulator 12 using a spread code generated by a spread code generator 13, and a wideband signal is generated. Is radiated by the antenna 16. As the spreading code, a pseudo noise sequence (PN sequence) such as M sequence or Gordo sequence is used (see Japanese Patent Laid-Open No. 3-181235). Responder A, which has received the spread spectrum signal, modulates the received signal using the data in memory 18 using code modulator 17. Then, the modulated signal is radiated again by the antenna 16. The interrogator Q, which has received the wideband signal re-radiated from the transponder A by the antenna 16, performs spread demodulation using the spread demodulator 15 with the same spread code sequence as at the time of modulation, and narrows the spread spectrum wideband signal into a narrow band. Turn into. Further, by demodulating this signal by the code demodulator 14, the data held by the responder A can be read.

In the discriminating apparatus of the present invention, when noise from another device is received by the interrogator Q, the received noise is dispersed into a wide band signal by the spread demodulator 15, so that the code at the subsequent stage is encoded. The effect on the demodulator 14 is significantly reduced. Further, regarding the influence of the interrogation signal from another interrogator Q installed near, by using different spreading codes, the signals from the other interrogators Q have a wide band even after passing through the spreading demodulator 15. Since it remains dispersed in the signal, it is not affected as in the case of noise.

Further, in the identification device of the present invention, the responder A
Since there is no spreading code generator or spreading modulator on the side of, the current consumption is small, the size and weight can be reduced, and the life of the built-in battery can be extended. Moreover, since the number of the responders A is generally larger than the number of the interrogators Q installed, the cost of the entire system can be reduced.

[0013]

According to the present invention, in a mobile unit identification device comprising a transponder attached to a mobile unit and an interrogator that communicates with the transponder in a non-contact manner, the interrogator transmits the interrogation signal to the interrogation signal transmission unit. Since the code modulation means is provided and the response signal receiving section of the interrogator is provided with the spread code demodulation means,
Even if noise from other devices is received by the interrogator,
The received noise is spread and demodulated and spread over a wide frequency band, and for the interference waves from other interrogators installed nearby, the spreading code used is different, The band of the interference wave remains diffused even after the spread demodulation, and there is an effect that the original reception operation is not affected. Further, in the present invention, since the spread modulation means and the spread demodulation means are both provided on the side of the interrogator, it is possible to reduce the size and weight of the transponder and further reduce the current consumption, so that the built-in battery has a long life. There is an effect that can be achieved.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an embodiment of a moving object identifying apparatus of the present invention.

FIG. 2 is a block circuit diagram of a conventional mobile body identification device.

FIG. 3 is a block circuit diagram of a mobile body identification device using a conventional spread modulation / demodulation method.

[Explanation of symbols]

 Q Interrogator A Responder 11 Carrier oscillator 12 Spreading modulator 13 Spreading code generator 14 Code demodulator 15 Spreading demodulator 16 Antenna 17 Code modulator 18 Memory

Claims (1)

[Claims] 1. A mobile body identifying device comprising a transponder attached to a mobile body and an interrogator for communicating with the transponder in a non-contact manner, wherein a spread code modulation means is provided in an interrogation signal transmitter of the interrogator. At the same time, a mobile body identification device characterized in that a spread code demodulating means is provided in a response signal receiving section of the interrogator.