JPH07250011A - Non-contact communication equipment and data carrier used therefor - Google Patents

Abstract

PURPOSE:To surely control reverberation without delaying timing even at the time of long distance communication concerning the non-contact communication equipment for intermitting a high frequency signal at a fixed duty ratio and for transmitting signals corresponding to the presence/absence of its reverberation. CONSTITUTION:A counter 50 counts the number of pulses in a carrier from a signal, which carrier is intermitted, to be transmitted from a write/read control unit. When the count-up output of the counter 50 is set at the number of pulses at a time point to stop oscillation, the count-up output can be provided at that stop time point. Therefore, by generating a shant pulse based on this output, echo can be controlled without delaying timing.

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 read / write head 2 is provided with an oscillation circuit 15 and a transmission coil L1 connected to the oscillation circuit 15 as shown in the figure. 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 the reception control circuit 1
Given to 3. 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 voltage control circuit 32 and a full-wave rectification circuit 33 are connected to both ends of the resonance circuit 31. The voltage control circuit 32 limits the voltage level across the voltage control circuit 32 to a predetermined value or less. The full-wave rectifying circuit 33 full-wave rectifies the obtained signal and supplies it to each part of the data carrier as a power supply Vcc through the power supply circuit 34.

A DEM extraction circuit 35 is connected to one end of the resonance circuit 31. The DEM extraction circuit 35 converts the carrier of the transmission signal into a square wave by half-wave rectifying and shaping the carrier of the transmission signal with the frequency of the carrier as the passing frequency, and the output thereof is given to the demodulation circuit 36. Further, the integration comparator circuit 37 is connected to one end of the resonance circuit 31. The integration comparator circuit 37 performs envelope detection of the signal obtained in the resonance circuit 31 and discriminates the power supply with a divided threshold value to extract the clock signal CKA and output its output to the demodulation circuit 36. . When the data carrier receives a signal, the demodulation circuit 36 counts the number of carrier pulses extracted by the DEM extraction circuit 35 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 38, necessary data is written in the memory 39, and the data is read from the memory 39. The output of the integration comparator circuit 37 is the falling pulse generation circuit 4
It is also given to 0. The falling pulse generation circuit 40 generates a short pulse at every falling of the pulse of the output CKA of the integration comparator circuit 37, and its output is given to the shunt pulse generation circuit 41. The NRZ signal read from the memory control unit 38 is converted into, for example, a serial bi-phase code by the conversion circuit 42 and input to the shunt pulse generation circuit 41. The shunt pulse generation circuit 41 generates a shunt pulse by the logical product of these, and is input to the shunt circuit 43. The shunt circuit 43 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)-
(F) shows the waveform of each part of a to f 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 output by the integration comparator circuit 37 from FIG. 6 (c), (d).
Are integrated and converted into a clock signal CKA. Then, from the data carrier 3 to the read / write head 2
When the signal is transmitted to the side, a shunt pulse is generated by the read signal from the memory 39, for example, as shown in FIG. 6 (e), which controls the reverberation. Therefore, when this signal is received by the receiving side of the read / write head, the signal is received as shown in FIG. 6 (f), and since the level differs depending on the presence or absence of reverberation, the signal from the data carrier can be received.

[0008]

However, in such a conventional non-contact communication device, when the data carrier is separated from the read / write head, the level of the resonance waveform shown in FIG. 6 (b) is lowered. The integrating comparator circuit 37 integrates and discriminates this waveform, but the threshold value is also set by the resistance ratio, so that the level decreases. On the other hand, when the transmission of the resonance waveform is stopped, the rate of decrease of the level does not change. Therefore, as shown in FIG. 6D, the falling timing of the clock CKA for discriminating the integrated waveform is from the time when the transmission waveform of the read / write head 2 is stopped. It will be significantly delayed. In the case of long-distance communication, this delay time Δt becomes large, and since the shunt pulse is generated at the time of this fall, the shunt pulse generation timing is also delayed. If the delay time becomes long, the timing is delayed even when the reverberation is stopped, so that there is a drawback that the read / write head cannot discriminate the signal depending on the presence or absence of the reverberation.

The present invention has been made in view of such conventional problems, and can normally perform communication even when the falling point of the clock signal CKA in the data carrier is delayed in the case of long-distance communication. This is a technical issue.

[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 includes a transmission control circuit that generates a transmission signal having a constant duty ratio when receiving data, and a first coil provided on a surface facing the data carrier, An oscillator 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 waveform-shaping a signal obtained in the second coil. A reception control circuit for reading data by the data carrier, wherein the data carrier has a resonance circuit including a third coil provided facing the write / read control unit; The demodulation circuit that demodulates the signal based on the envelope signal of the resonance signal received by the oscillation circuit, and the carrier pulse of the transmission signal that is obtained from the resonance circuit are counted, and near the oscillation stop time at the predetermined duty ratio during data reception. A counter that outputs a count output at a predetermined value of a carrier pulse, a memory, a memory control unit that controls the memory based on a signal obtained from a demodulation circuit, and an oscillator circuit that outputs a count output having a predetermined value from the counter. Reverberation control means for controlling the reverberation of the resonance circuit while the oscillation signal stops,
It is characterized by having.

According to a third 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 a transmission signal obtained by the resonance circuit. A memory control that counts the carrier pulses and outputs a count output at a predetermined value of the carrier pulse near the oscillation stop time at a predetermined duty ratio during data reception, a memory, and a memory that controls the 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 signal of the oscillation circuit is stopped based on the count output of the predetermined value output from the counter.

[0012]

According to the non-contact communication device and the data carrier of claims 1 and 3 of the present invention having such characteristics, the writing / reading control unit outputs the intermittent transmission signal at a constant duty ratio when receiving the data. is doing. When the data carrier receives this signal, the number of carrier pulses of the transmission signal is counted by the counter, and when it reaches a predetermined value, a count-up signal is output. The data carrier outputs to the reverberation control means when transmitting data to the write / read control unit side. The reverberation control means generates a shunt signal by the logical product of the transmission data and the count-up signal, and controls the reverberation generated in the resonance circuit. In this way, 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. Therefore, even when the signal level obtained in the resonance circuit decreases. The timing of shunt pulse generation can be ensured, and data communication can be 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 will be 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 voltage control circuit 3 as in the conventional example.
2, the full-wave rectification circuit 33, the power supply circuit 34, and the DEM extraction circuit 35 are connected. Further, an integration comparator circuit 37 is connected to the resonance circuit 31, CKA is extracted, and a demodulation circuit 36 demodulates the received signal. Now, in this embodiment, the output of the DEM extraction circuit 35 is input to the counter 50. The counter 50 overflows with a duty ratio when transmitting a signal from the read / write head 2 to the data carrier 30, for example, a count value corresponding to the number of carrier pulses at the time when the transmission is almost finished at a duty of 50%, and generates a CNTOUT output. It is a counter that does. For example, in the case of the present embodiment, the CNTOUT output is output to the shunt pulse generation circuit 41 when the 13 pulses of the DEM signal are counted. The configurations of the memory control unit 38, the memory 39, and the conversion circuit 42 are the same, and the output of the conversion circuit 42 is given to the shunt pulse generation circuit 41. The shunt pulse generation circuit 41 is the CN of the counter 50.
A shunt signal is output by a logical product of the TOUT output and the output of the conversion circuit 42. The output is given to the shunt circuit 43. The shunt circuit 43 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 41 and the shunt circuit 43 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. 3A to 3I are shown in FIG.
It is a wave form diagram which shows the wave form of each part of a to i of FIG. Figure 3
(A) is a duty ratio of 50% that is oscillated from the oscillation circuit of the read / write head and transmitted to the data carrier 30 side via the transmission coil L1, that is, oscillated with the same time width,
The transmission waveform which repeats stop is shown. When the data carrier 30 is in a position where it can communicate with the read / write head 1, when this signal is received, the resonance waveform shown in FIG. 3B is obtained. FIG. 3C shows the DEM output of the DEM extraction circuit 35, and this carrier pulse is counted by the counter 50. The count value of the counter 50 is "1.
3 ”, the CNTOUT signal is output from the counter 50 as shown in FIG. Further, as in the case of the conventional example described above, the DC waveform of the integration is integrated by the integration comparator circuit 37, and the DC resonance waveform is discriminated by the threshold value corresponding to the voltage level at that time, and as shown in FIG. The signal CKA is output. In this case, like the conventional example, when the data carrier is separated from the read / write head, the fall of CKA is delayed as compared with the fall of the transmission waveform. However, in this embodiment, the counter 50
When the count value of the DEM signal, for example, 13 is counted, the CNTOUT signal is output, thereby forming a shunt pulse. Therefore, as shown in FIG.
A shunt pulse will be output before the fall of KA. Here, the signal read from the memory 39 is converted into, for example, a bi-phase code by the conversion circuit 42. When the converted signal is shown in FIG. 3H, a shunt pulse is output to the shunt circuit 43 during the H level. Therefore, the reverberation stops while the shunt pulse is output, as shown in FIG. Then, the level of the signal received by the receiving coil L2 of the read / write head 2 also changes depending on the presence / absence of the shunt pulse as shown in FIG. Here, since the shunt pulse is generated by counting the number of carrier pulses, its timing does not delay like the clock signal CKA even when the level of the resonance signal decreases, and the shunt pulse is generated at a predetermined timing. Can be generated. Therefore, data communication can be performed even at a long distance, which is not possible with the conventional non-contact communication device.

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 35 rectifies the waveform by half-wave rectification 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, the resonance waveform of the data carrier is identified to form the clock signal. On the other hand, the number of pulses of the received signal is counted and a shunt pulse for controlling reverberation is output with a predetermined count value. Therefore, even if the level of the resonance waveform is lowered by long-distance communication, the time of the shunt pulse can be accurately defined, so that the effect of long-distance data communication can be obtained.

[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 17,36 Demodulation circuit 35 DEM extraction circuit 37 Integral comparator circuit 38 Memory control Part 39 Memory 41 Shunt pulse generation circuit 42 Conversion circuit 43 Shunt circuit 50 Counter

Claims (3)

[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. Is a transmission control circuit for generating a transmission signal having a constant duty ratio when receiving data, and a first coil provided on a surface facing the data carrier. A reception control circuit that includes an oscillation circuit that intermittently oscillates on the basis of a second coil, and a second coil that is provided on a surface that faces the data carrier, and that reads the data by shaping the waveform of the signal obtained in the second coil. And 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, a carrier pulse of a transmission signal obtained from the resonance circuit, and a data reception time A counter that outputs a count output at a predetermined value of a carrier pulse near the oscillation stop time at a predetermined duty ratio of, a memory, a memory control unit that controls the memory based on a signal obtained from the demodulation circuit, and an output from the counter. And a reverberation control unit that controls reverberation of the resonance circuit while the oscillation of the oscillation circuit is stopped based on the counted output of the predetermined value. 2. The non-contact communication device according to claim 1, wherein the data carrier is attached to an article to be identified and holds the data in the memory. 3. 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 counting carrier pulses of a transmission signal obtained from the resonance circuit. A counter that outputs a count output at a predetermined value of a carrier pulse near an oscillation stop time at a predetermined duty ratio at the time of receiving data, 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.