JP2004350140A - Data detecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data detecting apparatus which dispenses with a bisector for bisecting a transmission carrier and a response signal from an identification target, and consequently has simple constitution and is made low-cost accordingly. <P>SOLUTION: A transmitting part 11 of a data detecting apparatus 40 outputs the transmission carrier after modulating its amplitude with an inquiry signal, and transmits it to a non-contact ID tag 30 via a directional coupler 12, a circulator 13 and an antenna 14. A directional coupler 12 extracts a part of the transmission carrier and inputs it to one terminal of a transmission line 41. Besides, the circulator 13 extracts the response signal which is outputted from the non-contact ID tag 30 and received by the antenna 14 and inputs it to the other terminal of the transmission line 41. Mixers 16a, 17a of receiving systems 16, 17 are connected at the interval of about λg/8 to the transmission line 41. The mixers 16a, 17a applies demodulation processing to signal inputted from the directional coupler 12 and the circulator 13 via the transmission line 41. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a data detection device that detects a response signal transmitted from a contactless ID tag to an inquiry signal.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a system has been put to practical use in which a non-contact ID tag (response device) is attached to a product, an article, or the like, and non-contact reading of unique identification data preset on the ID tag is performed by a data detection device. Further, in addition to the ID tag, a system for reading data stored in an IC card or the like in a non-contact manner by a data detection device has been put to practical use (for example, see Patent Document 1).
[0003]
FIG. 4 shows a conventional configuration example of a data detection system using a non-contact ID tag.
In FIG. 4, reference numeral 10 denotes a data detection device, which includes a transmission unit 11. The transmitting unit 11 amplitude-modulates a transmission carrier (not shown), which is an output of an oscillator, with an inquiry signal from the control circuit 22 and a clock, and amplifies and outputs the result with a transmission amplifier. The transmission signal output from the transmission unit 11 is transmitted to the antenna 14 via the directional coupler 12 and the circulator 13, and transmitted from the antenna 14 to the non-contact ID tag 30.
[0004]
A part of the transmission carrier wave input from the transmission unit 11 to the directional coupler 12 is extracted by the directional coupler 12 and input to the first two-way splitter 15 to be split into two. The transmission carrier wave split into two by the first splitter 15 is input to the mixer 16a of the first receiving system 16 and the mixer 17a of the second receiving system 17.
[0005]
The non-contact ID tag 30 includes, for example, an antenna 31, a modem 32, a controller 33, and a memory 34. The memory 34 stores unique ID data in advance. The non-contact ID tag 30 receives the transmission carrier wave transmitted from the data detection device 10 with the antenna 31, detects and smoothes this carrier wave with the modem 32, converts the carrier wave into a DC voltage, and sends the DC voltage to the controller 33 and the memory 34. Supply as Further, the modem 32 extracts a clock and an inquiry signal from the received carrier wave and inputs the clock and the inquiry signal to the controller 33. The controller 33 reads the content stored in the memory 34 in response to the inquiry signal from the data detection device 10 and outputs the read content to the modem 32 as a response signal. The modulator / demodulator 32 modulates the amplitude of the transmission carrier from the data detection device 10 according to the response signal from the controller 33, and re-radiates the carrier to the data detection device 10 as a return wave.
[0006]
The data detection device 10 receives the return wave from the non-contact ID tag 30 with the antenna 14, inputs the return wave from the circulator 13 to the second splitter 18, and splits it into two. One of the received waves split into two by the splitter 18 is directly input to the mixer 16 a of the first receiving system 16, and the other of the received waves is phase-shifted by 90 ° by the phase shifter 19, and Is input to the mixer 17a.
[0007]
The first receiving system 16 and the second receiving system 17 are split into two by two splitters 15 and 18 and convert a received wave input directly or via a phase shifter 19 and a carrier wave from the transmitting unit 11 into a mixer 16a. , 17a to extract a baseband component (demodulated output), and further output through low-pass filters 16b, 17b and reception amplifiers 16c, 17c. Then, the output signals of the receiving amplifiers 16c and 17c, that is, the output signals of the first receiving system 16 and the second receiving system 17 are added and combined by the combining amplifier 20.
[0008]
The demodulated response signal output from the synthesizing amplifier 20 is converted into digital data by a level converter 21 and sent to a control circuit 22. The control circuit 22 further sends a host device such as a personal computer (not shown). Sent to
[0009]
The reason why the first receiving system 16 and the second receiving system 17 are provided in the demodulation system is that, in the case of one receiving system, the transmission carrier and the non- This is because the phase difference of the signal from the contact ID tag 30 changes and a part that cannot be received occurs. One of the received waves split into two by the second splitter 18 is phase-shifted by 90 ° by the phase shifter 19 and the outputs of the receiving systems 16 and 17 are combined to stably extract the response signal. Points that cannot be received can be avoided.
[0010]
[Patent Document 1]
JP-A-11-220424
[Problems to be solved by the invention]
In the above-described conventional data detection device 10, when the response signal from the identification target such as the non-contact ID tag 30 is configured to avoid a point that cannot be received, the two divider 15 that distributes a part of the transmission carrier wave is provided. The two dividers 18 for distributing the response signal from the non-contact ID tag 30 and the phase shifter 19 are required, resulting in a problem that the configuration becomes complicated and the cost increases.
[0012]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and does not require a distributor and a phase shifter for distributing a response signal from a transmission carrier and an identification target, thereby simplifying the configuration and reducing the cost. It is an object to provide a data detection device.
[0013]
[Means for Solving the Problems]
The data detection device according to the present invention is a transmission unit that outputs a transmission signal obtained by modulating a transmission carrier with an inquiry signal, and transmits the transmission signal output from the transmission unit to the identification target and transmits the transmission signal from the identification target. An antenna that receives a response signal of the above, a directional coupler that extracts a part of a transmission carrier output from the transmitting unit, a circulator that extracts a response signal from the identification target via the antenna, and the direction A transmission path in which a transmission carrier extracted by a sex coupler and a response signal from the identification object extracted by the circulator are input to both ends; and a plurality of reception systems connected to the transmission path at regular intervals. And characterized in that:
[0014]
By providing a transmission path in which both ends are connected to the directional coupler and the circulator as described above, the carrier wave from the transmission unit and the return wave from the identification object can be distributed and supplied to a plurality of reception systems, respectively. , The distributor can be omitted. Also, by setting the interval between the connection points of the receiving system in the transmission path to a value such as λg / 8, λg / 16, etc., the phases of the carrier wave from the transmission unit and the return wave from the object to be identified can be set to desired values. The delay can be delayed, and the same operation as that provided with the phase shifter can be performed.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an example of a configuration in a case where the present invention is applied to a data detection system using a non-contact ID tag. The same parts as those in the conventional example shown in FIG. Omitted.
[0016]
As shown in FIG. 1, the transmission unit 11 of the data detection device 40 amplitude-modulates, for example, a 2.45 GHz transmission carrier with an inquiry signal from the control circuit 22 and a clock, amplifies the transmission carrier with a transmission amplifier, and outputs the amplified signal. The transmission signal output from the transmission unit 11 is transmitted to the antenna 14 via the directional coupler 12 and the circulator 13, and transmitted from the antenna 14 to the non-contact ID tag 30.
[0017]
The directional coupler 12 extracts a part of the transmission carrier output from the transmission unit 11 and inputs it to one end of the transmission path 41.
[0018]
The circulator 13 extracts a response signal from the non-contact ID tag 30 received by the antenna 14 and inputs the response signal to the other end of the transmission path 41. The transmission line 41 is constituted by, for example, a microstrip line having an impedance of 50Ω and has a length of at least λg / 8 or more. The mixer 16a and the mixer 17a of the second receiving system 17 are connected. Here, λg is the wavelength of the transmission carrier and the response signal transmitted by the transmission path 41.
[0019]
Other configurations, that is, the configurations of the receiving systems 16 and 17 and the non-contact ID tag 30 as the identification target are the same as those of the conventional one shown in FIG. 4 described above, and thus detailed description is omitted.
[0020]
Next, a specific configuration example of the transmission path 41, the mixer 16a of the first receiving system 16, and the mixer 17a of the second receiving system 17 will be described with reference to FIGS. FIG. 2 shows a configuration example in which the transmission line 41 and the mixers 16a and 17a are arranged on a substrate, and FIG. 3 shows a circuit configuration example.
[0021]
In FIG. 2, reference numeral 51 denotes a circuit board on which a transmission line 41 is formed by a microstrip line. The circuit board 51 is provided with the directional coupler 12 at one end of the transmission path 41 and the circulator 13 at the other end. Further, the circuit board 51 is provided with a mixer 16a of the first receiving system 16 and a mixer 17a of the second receiving system 17 along the transmission line 41, and the input terminals t1 thereof are connected to DC blocking capacitors 52 and 53, respectively. Is connected to the transmission line 41 via the. In this case, the interval between the connection points of the capacitors 52 and 53 on the transmission line 41 is set to about λg / 8.
[0022]
Each of the mixers 16a and 17a has three terminals t1 to t3, where t1 is an input terminal, t2 is an output terminal, and t3 is a ground terminal. The output terminals t2 of the mixers 16a and 17a are connected to the low-pass filters 16b and 17b shown in FIG. 1 via circuit patterns 54 and 55, respectively, and the ground terminal t3 is connected to a ground pattern 56.
[0023]
As shown in FIG. 3, the mixers 16a and 17a each include a pair of detection diodes D1 and D2. For example, the anode of the diode D1 and the cathode of the diode D2 are collectively connected to form an input terminal t1. Is connected to the capacitor 52 or 53. Further, the cathode side of the diode D1 becomes an output terminal t2, and a detection output is taken out from this output terminal t2 and connected to the mixer 16a or the mixer 17a. The anode side of the diode D2 serves as the ground terminal t3, and is connected to the ground pattern 56 and grounded as described above.
[0024]
In the above configuration, the transmitting unit 11 amplitude-modulates the transmission carrier with the inquiry signal and the clock from the control circuit 22, amplifies the carrier with the transmission amplifier, and outputs the amplified signal. The transmission signal output from the transmission unit 11 is transmitted to the antenna 14 via the directional coupler 12 and the circulator 13, and transmitted from the antenna 14 to the non-contact ID tag 30.
[0025]
A part of the transmission carrier wave input from the transmission unit 11 to the directional coupler 12 is extracted by the directional coupler 12 and input to the mixer 16 a of the first reception system 16 via the transmission line 41. At the same time, the signal is further delayed by the transmission length of λg / 8, that is, the phase is delayed by 45 ° and input to the mixer 17a of the second receiving system 17.
[0026]
The return wave from the non-contact ID tag 30 is received by the antenna 14 and input from the circulator 13 to the mixer 17a of the second receiving system 17 via the transmission line 41, and further has a transmission length of λg / 8. Is input to the mixer 16a of the first receiving system 16 with a phase delay of 45 °.
[0027]
The mixer 16a of the first reception system 16 converts the carrier wave transmitted from the transmission unit 11 via the directional coupler 12 and the return wave from the non-contact ID tag 30 whose phase is delayed by 45 ° in the transmission path 41. Mixing and diode detection are performed, and output to the receiving amplifier 16c via the low-pass filter 16b.
[0028]
Further, the mixer 17a of the second receiving system 17 transmits the carrier transmitted from the transmitting unit 11 via the directional coupler 12 and the transmission path 41 with a phase delayed by 45 ° via the antenna 14 and the circulator 13. The signal is mixed with the return wave from the non-contact ID tag 30 for diode detection, and is output to the receiving amplifier 17c via the low-pass filter 17b.
[0029]
By providing the transmission path 41 having both ends connected to the directional coupler 12 and the circulator 13 as described above, the carrier wave from the transmission unit 11 and the return wave from the non-contact ID tag 30 can be respectively transmitted to the first reception system. It can be distributed and supplied to the 16 mixers 16a and the mixer 17a of the second receiving system 17. By setting the distance between the connection points of the mixers 16a and 17a in the transmission path 41 to λg / 8, the phases of the carrier wave from the transmission unit 11 and the return wave from the non-contact ID tag 30 are each delayed by 45 °. Thus, an operation equivalent to that provided with a 90 ° phase shifter can be performed.
[0030]
As a result, if the non-contact ID tag 30 is located within the responsive range with respect to the data detection device 40, regardless of the position of the non-contact ID tag 30, the first reception system 16 and the second reception system The response signal of the non-contact ID tag 30 can always be detected from at least one of the seventeen.
[0031]
By providing the transmission line 41 having a length of λg / 8 or more as described above, it is possible to perform the same operation as the conventional two-way divider and 90 ° phase shifter, simplify the circuit configuration, and reduce the cost. Reduction can be achieved.
[0032]
In the above-described embodiment, the case where two receiving systems, that is, the first receiving system 16 and the second receiving system 17 are provided has been described. However, even when more receiving systems, for example, four receiving systems are provided. This can be implemented in the same manner as in the above embodiment. When four receiving systems are provided, the mixers of each receiving system are connected to the transmission line 41 at intervals of about λg / 16, so that response signals from the non-contact ID tag 30 can be received more smoothly. be able to.
[0033]
Further, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements in an implementation stage without departing from the scope of the invention.
[0034]
【The invention's effect】
According to the present invention as described in detail above, a transmission signal formed by modulating a transmission carrier with an inquiry signal is transmitted to the identification target, and a data detection device that receives a response signal returned from the identification target, By connecting both ends of the transmission path to a directional coupler for extracting a part of the transmission carrier and a circulator for extracting a response signal from the identification object, and connecting a plurality of reception systems at predetermined intervals to the transmission path , The phases of the carrier wave from the transmission unit and the return wave from the identification target can be delayed and mixed. As a result, it is possible to perform the same operation as that provided with the conventional distributor and phase shifter, thereby simplifying the configuration and reducing the cost.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a data detection system according to an embodiment of the present invention.
FIG. 2 is a view showing a specific configuration example of a main part in the embodiment.
FIG. 3 is a diagram showing a circuit configuration of a mixer part in the embodiment.
FIG. 4 is a block diagram showing a configuration of a conventional data detection system.
[Explanation of symbols]
Reference Signs List 11 transmitting unit 12 directional coupler 13 circulator 14 antenna 16 first receiving system 16a mixer 16b low-pass filter 16c receiving amplifier 17 second receiving system 17a mixer 17b low-pass filter 17c Receiving amplifier 20 Synthetic amplifier 21 Level converter 22 Control circuit 30 ID tag 31 Antenna 32 Modulator / demodulator 33 Controller 34 Memory 40 Data detector 41 Transmission line 51 Circuit boards 52 and 53 Capacitors 54, 55 Circuit pattern 56 Earth pattern

Claims (3)

A transmission unit that outputs a transmission signal formed by modulating a transmission carrier with an inquiry signal, and an antenna that transmits a transmission signal output from the transmission unit to the identification target and receives a response signal from the identification target, A directional coupler that extracts a part of the transmission carrier output from the transmission unit, a circulator that extracts a response signal from the identification target via the antenna, and a transmission carrier that is extracted by the directional coupler And a transmission path through which a response signal from the identification object extracted by the circulator is input to both ends, and a plurality of reception systems connected to the transmission path at regular intervals. Data detection device. 2. The data detecting device according to claim 1, wherein two systems are provided as the receiving system, and each receiving system is connected to the transmission line at an interval of about λg / 8. 2. The data detecting device according to claim 1, wherein four receiving systems are provided, and each receiving system is connected to the transmission line at an interval of about λg / 16.

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