JPH08316887A - Contactless communication equipment and data carrier used for it - Google Patents

Abstract

PURPOSE: To prevent interruption of data from being lost due to echo in the case of near distance communication in the contactless communication equipment where a high frequency signal is intermitted by 1st and 2nd duty factors and the signal is sent by the duty factors. CONSTITUTION: A counter 50 counts number of pulses of a carrier from a signal whose carrier is interrupted sent from a write/read control unit. A count-up output of the counter 50 is set to number of pulses when a signal is stopped at a 2nd duty factor. Thus, a count-up output is obtained when the signal is stopped. Then a shunt pulse is generated based on it to control the echo. Thus, data are sent surely even when data carriers are close to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a physical distribution system for managing tools and products, a non-contact communication device used for identifying a human body, and a data carrier used for the same.

[0002]

2. Description of the Related Art Conventionally, a system for identifying and managing various articles such as tools, parts and products in order to mechanize the management of tools of machine tools and the identification of parts and products in an assembly and conveyance line in a factory. Is required. Therefore, JP-A-1-151831
As shown in the item No., a memory unit (data carrier) having a memory is provided in the identification object, and necessary information is written in such a memory by data transmission from the outside, and the information is stored as necessary. There has been proposed a non-contact communication device adapted to read out.

Such a conventional non-contact communication device is shown in FIG.
As shown in FIG. 3, it is composed of a write / read control unit including an ID controller 1 and a read / write head 2 and a data carrier 3. The read / write head 2 intermittently oscillates at a constant frequency to transmit a signal to the data carrier 3 side. When receiving data, a signal with a constant duty ratio is sent to control reverberation by a resonance circuit in the data carrier. . In the read / write head 2, the signal is received by determining the presence or absence of this reverberation by the resonance circuit.

In FIG. 4, the write / read control unit is I
It has a D controller 1 and a read / write head 2. The ID controller 1 has a transmission control circuit 11, a reference clock generation circuit 12, and a reception control circuit 13. The transmission control circuit 11 has first and second duty ratios corresponding to the transmission data signal when transmitting data from the read / write head 2 side to the data carrier 3, and a constant third duty ratio when receiving data, for example, It is for generating a transmission signal of a constant frequency which is intermittent with a duty ratio of 50%. The first duty ratio is, for example, 30%, the second
The duty ratio of is, for example, 70%. The read / write head 2 includes an oscillator circuit 15 and an oscillator circuit 15 as shown in the figure.
A coil L1 for transmission connected to is provided. The coil L1 is provided on the surface facing the data carrier 3. The oscillator circuit 15 is an oscillator circuit that oscillates at a constant frequency under the control of the transmission control circuit 11. Further, the receiving circuit is provided with a resonance circuit 16 including a coil L2 and a capacitor C1. The output of the resonance circuit 16 is demodulated by the demodulation circuit 17 and given to the reception control circuit 13. Also, the receiving coil L2 is provided on the surface facing the data carrier similarly to the coil L1.

FIG. 5 is a block diagram showing the structure of a conventional data carrier 3. In the figure, the data carrier 3 has a resonance circuit 31. The resonance circuit 31 is the coil L3.
And a capacitor C2 connected in parallel with the coil L3. A full-wave rectification circuit 32 is connected to both ends of the resonance circuit 31. The full-wave rectification circuit 32 performs full-wave rectification on the obtained signal and supplies it as a power supply Vcc to each part of the data carrier via the power supply circuit 33.

A DEM extraction circuit 34 is connected to one end of the resonance circuit 31. The DEM extracting circuit 34 converts the carrier of the transmission signal into a square wave by half-wave rectifying and shaping the carrier of the transmission signal as a passing frequency, and its output is given to the demodulation circuit 35. Further, the integration comparator circuit 36 is connected to one end of the resonance circuit 31. The integration comparator circuit 36 performs envelope detection of the signal obtained in the resonance circuit 31, discriminates the power supply with a threshold value obtained by dividing the power supply, extracts the clock signal CKA, and outputs the output to the demodulation circuit 35. . When the data carrier receives a signal, the demodulation circuit 35 counts the number of carrier pulses extracted by the DEM extraction circuit 34 based on CKA, and determines either the H level or the L level depending on the duty ratio of intermittent transmission. To do. The signal thus demodulated is separated into a command and data by the memory control unit 37, necessary data is written in the memory 38, and data is read from the memory 38. The NRZ signal read from the memory control unit 37 is converted into the conversion circuit 4
It is converted into a serial bi-phase code by 0 and input to the shunt pulse generation circuit 39. The shunt pulse generation circuit 39 generates a shunt pulse by the logical product of these, and is input to the shunt circuit 41. The shunt circuit 41 has a pair of switching elements that ground both ends of the resonance circuit 31 based on a shunt pulse, and grounds both ends of the resonance circuit at the same time to stop reverberation in a short time.

Next, the waveform of each part of the read / write head and the data carrier will be described. FIG. 6 (a)-
(D) shows the waveform of each part of a to d of FIGS. FIG. 6A shows a transmission waveform transmitted from the transmission unit of the read / write head. When this signal is received by an adjacent data carrier 3, its resonant circuit 31
, The resonance waveform shown in FIG. 6B is obtained. This signal is integrated by the integration comparator circuit 36,
It is converted into a clock signal CKA as shown in (c).
When a signal is transmitted from the read / write head 2 to the data carrier 3, as shown in FIG. 6A, the duty ratio is the first duty ratio (30%) and the second duty ratio (70%). Thus, the data is appropriately switched and transmitted. The data carrier receives this signal, and the DEM extraction circuit 34 extracts and counts the pulse number of the carrier included in the signal whose CKA is at H level. The number of pulses and a predetermined threshold value, for example, 15 or less, the first duty ratio, and 18 or more, the second duty ratio are used to identify the signal sent from the read / write head.

[0008]

However, in the conventional data carrier 3, the Q of the coil of the resonance circuit 31 is set high so that communication can be reliably performed even if the data carrier 3 is located away from the read / write head 2. As a result, when the data carrier 3 is close to the read / write head 2, as shown in FIG.
There is a drawback that the resonance waveform of the data carrier shown in (b) is less deteriorated and the fall of CKA is extended.
Therefore, when the data carrier is sufficiently close to the read / write head and a signal having a duty ratio of 70% is transmitted from the read / write head 2 to the data carrier 3, transmission of the next cycle is performed before the resonance waveform falls. However, the CKA cannot be counted continuously and the communication cannot be normally performed.

The present invention has been made in view of such conventional problems, and an object thereof is to ensure that a signal can be transmitted even when a data carrier is close to a read / write head. .

[0010]

The invention of claim 1 of the present application is a contactless communication comprising a data carrier and a write / read control unit for transmitting data to the data carrier and receiving the transmitted data. In the device, the write / read control unit is provided on a surface facing a data carrier, and a transmission control circuit that generates a transmission signal having a first duty ratio and a second duty ratio higher than the duty ratio during data transmission. A second coil including a first coil, an oscillation circuit that intermittently oscillates based on a transmission signal given from a transmission control circuit, and a second coil provided on a surface facing a data carrier. And a reception control circuit for reading data by waveform-shaping the obtained signal, and the data carrier is provided facing the write / read control unit. A resonance circuit including the coil of No. 3, a demodulation circuit that demodulates a signal based on an envelope signal of a resonance signal received by the resonance circuit, and a carrier pulse of each transmission signal obtained from the resonance circuit is counted to receive data. A counter, which outputs a count output at a predetermined value of the number of carrier pulses that exceeds the oscillation stop time of the second duty ratio at the time, a memory,
A memory control unit that controls the memory based on a signal obtained from the demodulation circuit, and a reverberation control unit that controls the reverberation of the resonance circuit while the oscillation of the oscillation circuit is stopped based on the count output of a predetermined value output from the counter. And are included.

According to a second aspect of the present invention, a resonance circuit including a coil, a demodulation circuit for demodulating a signal based on an envelope signal of a resonance signal received by the resonance circuit, and respective transmission signals obtained from the resonance circuit. A counter that counts carrier pulses of a signal and outputs a count output at a predetermined value of the number of carrier pulses that exceeds the oscillation stop time of the second duty ratio at the time of data reception, a memory, and a memory based on a signal obtained from a demodulation circuit. And a reverberation control means for controlling the reverberation of the resonance circuit while the oscillation of the oscillation circuit is stopped based on the count output of a predetermined value output from the counter. Is.

[0012]

According to the non-contact communication device and the data carrier of claim 1 of the present application having such characteristics, the write / read control unit causes the transmission signal intermittently interrupted at the first and second duty ratios when transmitting data. Is being output. When the data carrier receives this signal, the counter counts the number of carrier pulses of the transmission signal and outputs a count-up signal at the end of transmission of the carrier having the second duty ratio.
The data carrier thereby produces a shunt signal,
It controls the reverberation that occurs in the resonant circuit. As described above, since the shunt signal is not formed based on the envelope signal obtained in the resonance circuit but the shunt signal is generated by counting the transmission pulses, even when the signal level obtained in the resonance circuit rises. The clock can be reliably extracted, and data communication is ensured.

[0013]

2 is a block diagram showing the overall construction of a write / read control unit according to an embodiment of the present invention. In this figure, the same parts as those of the conventional example described above are designated by the same reference numerals, and detailed description thereof is omitted. Also in this embodiment, the configuration on the write / read control unit side is the same, and the ID controller 1
Has a transmission control circuit 11, a reference clock generation circuit 12, and a reception control circuit 13. The transmission control circuit 11 has first and second duty ratios corresponding to the transmission data at the time of data transmission from the read / write head 2 side to the data carrier 30, and has a constant third duty ratio at the time of receiving the data, for example, 50. A transmission signal having a constant frequency, which is intermittent with a duty ratio of%, is generated. The read / write head 2 is provided with an oscillating circuit 15 and a transmitting coil L1 connected to the oscillating circuit 15 as shown in the drawing. Coil L
1 is provided on the surface facing the data carrier. The oscillator circuit 15 is an oscillator circuit that oscillates at a constant frequency under the control of the transmission control circuit 11. In addition, the receiving circuit has a coil L
2, a resonance circuit 16 including a capacitor C1 is provided. The output of the resonance circuit 16 is demodulated by the demodulation circuit 17 and given to the reception control circuit 13. The receiving coil L2 is also provided on the surface facing the data carrier 30, like the coil L1.

On the other hand, the data carrier 30 is used by being attached to, for example, an article to be identified, and holds data of the article. As shown in FIG. 1, the data carrier 30 includes a resonance circuit 31 and a full-wave rectification circuit 3 as in the conventional example.
2. The power supply circuit 33 and the DEM extraction circuit 34 are connected. Further, an integration comparator circuit 36 is connected to the resonance circuit 31, CKA is extracted, and a demodulation circuit 35 demodulates the received signal. Now, in this embodiment, the output of the DEM extraction circuit 34 is input to the counter 50. Counter 5
0 is the first and second duty ratios when the signal is transmitted from the read / write head 2 to the data carrier 30, for example, 3
When the duty ratio of 0% and 70% is to be transmitted, the second duty ratio 70% signal is transmitted, and the count value corresponding to the carrier pulse number at the time when the transmission is almost completed overflows, and CNTOUT Is a counter that produces the output of. For example, in the case of the present embodiment, the CNTOUT output is output to the shunt pulse generation circuit 39 when the 18 pulses of the DEM signal are counted. The configurations of the memory control unit 37, the memory 38, and the conversion circuit 40 are the same, and the output of the conversion circuit 40 is given to the shunt pulse generation circuit 39. The shunt pulse generation circuit 39
A shunt signal is output by the logical product of the CNTOUT output of the counter 50 and the output of the conversion circuit 40, and the output is given to the shunt circuit 41. The shunt circuit 41 has a pair of switching elements that ground both ends of the resonance circuit 31 based on a shunt pulse, and grounds both ends of the resonance circuit at the same time to stop reverberation in a short time. Here, the shunt pulse generation circuit 39 and the shunt circuit 41 constitute reverberation control means for controlling the reverberation of the resonance circuit 31 based on the count-up signal of the counter 50 and the signal to be transmitted.

Next, the operation of this embodiment will be described with reference to a time chart. 3 (a) to 3 (e) are shown in FIG.
It is a wave form diagram which shows the wave form of each part of a of FIG. FIG.
(A) shows a transmission waveform with a duty ratio of 30% and 70% which is oscillated from the oscillation circuit of the read / write head and transmitted to the data carrier 30 side through the transmission coil L1. The data carrier 30 is the read / write head 1.
If you receive this signal if you are in a position where you can communicate with
The resonance waveform shown in (b) is obtained. As in the conventional example, when the data carrier 30 approaches the read / write head 2, the falling edge of the DC resonance waveform is delayed compared to the falling edge of the transmission waveform. However, in this embodiment, the counter 50 is reset and starts counting each time the transmission signal rises. When the duty ratio is 30%, the count value does not reach 18, so the CNTOUT output is not output. However, when the duty ratio is 70%, the counter 50 outputs the CNTOUT output after the count value reaches 18. As a result, the shunt circuit 41 is passed through the shunt pulse generation circuit 39.
Is input to Therefore, when the signal transmitted from the read / write head has a duty ratio of 70%, reverberation disappears as shown in FIG. 3B, and this signal is added to the integral comparator circuit 36. Therefore, the DEM extraction circuit 34 outputs the DEM signal as shown in FIG. 3D, and the DEM signal shown in FIG.
The clock signal CKA is extracted as shown in (e). Therefore, the falling of 70% and the rising of the duty ratio of 30% are not coupled, and the signal can be demodulated accurately. Therefore, the conventional non-contact communication device can reliably perform data communication even at a short distance where a communication error may occur.

In the data carrier of this embodiment, the signal obtained in the resonance circuit 31 is rectified and used as the power source for each part of the data carrier. However, a battery is provided in the data carrier, and data is supplied to each part by this battery. It goes without saying that the same can be applied to carriers. Further, the DEM extraction circuit 34 performs half-wave rectification and waveform shaping to perform DEM.
Although it is a signal, full-wave rectification may be performed to shape the waveform. In this case, the count value of the counter 50 needs to be double that of the half-wave rectification.

[0017]

As described in detail above, according to the present invention, even when the Q of the resonance circuit of the data carrier is increased to enable data transmission over a long distance, the near distance can be improved. There is no risk of malfunction during distance communication, and reliable data transmission becomes possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing a structure of a data carrier according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a write / read control unit of the non-contact communication device according to the present embodiment.

FIG. 3 is a waveform diagram showing the waveform of each part of the non-contact communication device of this embodiment.

FIG. 4 is a block diagram showing an overall configuration of a conventional non-contact communication device.

FIG. 5 is a block diagram showing an example of a conventional data carrier.

FIG. 6 is a waveform diagram showing a waveform of each part of a conventional non-contact communication device.

[Explanation of symbols]

 1 ID Controller 2 Read / Write Head 3, 30 Data Carrier 11 Transmission Control Circuit 12 Reference Clock Generation Circuit 13 Reception Control Circuit 15 Oscillation Circuit 16, 31 Resonance Circuit 17, 35 Demodulation Circuit 34 DEM Extraction Circuit 36 Integral Comparator Circuit 37 Memory Control Part 38 Memory 39 Shunt pulse generation circuit 40 Conversion circuit 41 Shunt circuit 50 Counter

Claims (2)

[Claims] 1. A contactless communication device comprising: a data carrier; and a write / read control unit for transmitting data to the data carrier and receiving the transmitted data, wherein the write / read control unit. A transmission control circuit for generating a transmission signal having a first duty ratio and a second duty ratio higher than the duty ratio when transmitting data, and a first coil provided on a surface facing the data carrier, An oscillation circuit that intermittently oscillates based on a transmission signal given from a transmission control circuit, and a second coil provided on a surface facing the data carrier are included, and a signal obtained in the second coil is waveform-shaped A reception control circuit for reading data by the data carrier, wherein the data carrier is a third carrier provided facing the write / read control unit.
A resonance circuit including a coil, a demodulation circuit that demodulates a signal based on an envelope signal of a resonance signal received by the resonance circuit, and a carrier pulse of each transmission signal obtained from the resonance circuit is counted, A counter that outputs a count output at a predetermined value of the number of carrier pulses that exceeds the oscillation stop time of the second duty ratio at the time of reception, a memory, and a memory control unit that controls the memory based on a signal obtained from the demodulation circuit. A reverberation control unit that controls reverberation of the resonance circuit while oscillation of the oscillation circuit is stopped based on a count output of a predetermined value output from the counter. Communication device. 2. A resonance circuit including a coil, a demodulation circuit that demodulates a signal based on an envelope signal of a resonance signal received by the resonance circuit, and a carrier pulse of each transmission signal obtained from the resonance circuit. A counter that counts and outputs a count output with a predetermined value of the number of carrier pulses that exceeds the oscillation stop time of the second duty ratio at the time of receiving data, a memory, and the memory is controlled based on a signal obtained from the demodulation circuit. A reverberation control unit that controls reverberation of the resonance circuit while oscillation of the oscillation circuit is stopped based on a count output of a predetermined value output from the counter. And a data carrier.