JP3371792B2 - Card reader device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a card reader device for transmitting / receiving digital data to / from a contactless IC card by electromagnetic waves.

[0002]

2. Description of the Related Art FIG. 5 shows the structure of a conventional non-contact IC card reader / writer 14. In FIG. 5, in response to an instruction from the host computer 12, the controller 3 sends the transmission data to the modulator 51. The modulator 51 modulates the transmission data by a predetermined modulation method and sends it to the transmission amplifier 5. The transmission amplifier 5 amplifies the power of the signal and transmits the transmission electromagnetic wave from the transmission antenna 6 to the non-contact IC card as an electromagnetic wave. Further, the reception electromagnetic wave from the non-contact IC is received by the reception antenna 8, amplified by the reception amplifier 9, demodulated into reception data by the demodulator 52, sent to the controller 3, and transmitted to the host computer 12.

Further, as shown in FIG. 6, there are the following three methods as typical data modulation methods. The first is ASK modulation (Amplitude Shift Ke) that associates "1" and "0" of data with two kinds of amplitudes.
2), the second is FSK modulation (FrequencyS) that makes data "1" and "0" correspond to two types of frequencies.
(Hift Keying). Third is the data "
PSK modulation (Phase Shift Ke) that corresponds to 1 "and" 0 "with or without phase change of two types of radio waves
ying).

In the conventional non-contact IC card reader / writer, only one type of modulation system is supported in correspondence with the non-contact IC card modulation system as described above. For example, FSK
A reader / writer for a non-contact IC card that transmits and receives by a modulation method is disclosed in Japanese Patent Laid-Open No. 5-210768. This prior art can send and receive data by FSK modulation, but cannot send and receive data by other modulation methods.

[0005]

However, the above-mentioned conventional example is generally compatible with only one type of modulation method. The reason for this is that the circuit is different for each modulation system, and if it is attempted to support various modulation systems, the circuit becomes large and the cost also becomes high. However, the demodulation method may differ depending on the type of the non-contact IC card, and there is a problem that one non-contact IC card reader / writer cannot transmit / receive data. Moreover, since the analog system is usually used for the modulator and demodulator of the reader / writer for the non-contact IC card, the circuit tends to be complicated.

The present invention solves the above-mentioned problems of the prior art, and it is possible to transmit electromagnetic waves corresponding to respective non-contact IC cards having different demodulation methods, and the modulator and demodulator are simple and inexpensive. Non-contact I that does not become too high
An object is to provide a reader / writer device for C card.

[0007]

To achieve this object, a first means of the present invention is to provide a reference signal source for generating a reference signal having a constant frequency and a reference signal generated by the reference signal source. A frequency divider, an antenna for transmitting and receiving electromagnetic waves to and from the non-contact IC card, a modulator for performing PSK modulation or FSK modulation on transmission data and transmitting the data to the antenna, and any of the PSK modulation and the FSK modulation. A PSK / FSK switch for switching between performing and not performing, and a PSK demodulator for PSK demodulating data received from the antenna, wherein the modulator of the first means is a reference signal divided by the frequency divider.
Signal and transmission data are subjected to exclusive OR operation to perform PSK modulation
The PSK modulator is a PSK modulator.

[0008]

[0009]

The second means of the present invention is a constant frequency
A reference signal source for generating a number of reference signals, said reference signal source
Frequency divider that divides the generated reference signal and non-contact IC
The antenna that sends and receives electromagnetic waves to and from the
By performing PSK modulation or FSK modulation on the
To the transmitter, the PSK modulation and the FSK modulation.
PSK / FSK switching to switch which key to perform
PSK demodulation of the data received from the receiver and the antenna
The PSK demodulator of the first means is a PSK demodulator for performing PSK demodulation by performing an exclusive OR operation on the currently received data and the data received one bit before.

[0011]

With the above construction, the first means of the present invention has the effect that the corresponding electromagnetic waves can be transmitted to non-contact IC cards having different demodulation methods for PSK demodulation and FSK demodulation. .

Further, the second means of the present invention has an effect that the PSK modulator is simple and does not increase the cost.

Furthermore, the third means of the present invention has the effect that the FSK modulator is simple and does not increase the cost.

Furthermore, the fourth means of the present invention has the effect that the PSK demodulator is simple and does not increase the cost.

An embodiment of the present invention will be described below. 1
Is a reference signal source for generating a reference signal having a constant frequency, 2 is a frequency divider for dividing the reference signal generated by the reference signal source,
Reference numeral 6 is a transmission antenna for transmitting electromagnetic waves to the non-contact IC card, and 3 is a controller for transmitting a select signal S4 to the PSK / FSK switching 4 for switching between PSK modulation and FSK modulation and receiving received data. And 7 is PS
At the time of K modulation, the exclusive OR operation is performed with the transmission data S7 from the controller 3 and the clock signal reference signal S2 of 4254 Hz which is the result of dividing the reference signal S1 from the reference signal source 1 by the frequency divider 2 to obtain PSK. The first exclusive OR calculator 4 for producing and outputting the transmission data outputs either the reference signal S2 or the reference signal S3 or the PSK transmission data S8 according to the select signal S4 from the controller 3 to the transmission signal S5.
The data selector 5 outputs the transmission signal S5 to the transmission amplifier 5 and outputs the electromagnetic wave to the transmission antenna 6, and the transmission antenna 6 transmits the electromagnetic wave to the non-contact IC card 13. In addition, the data selector 4 and the frequency divider 2,
The first exclusive OR calculator 7 and the second exclusive OR calculator 11 constitute a modulator for performing PSK modulation or FSK modulation. 8 is a non-contact IC card 13
A receiving antenna for receiving the received electromagnetic wave S9 from the receiver, 9 is a receiver amplifier for amplifying the received electromagnetic wave S9 to obtain PSK received data S10, and 10 shifts the PSK received data in accordance with the reference signal S11 and holds 1-bit previous data. The shift register 11 includes a second exclusive OR calculator that performs exclusive OR operation on PSK received data and 1-bit previous data to create received data. The non-contact IC card reader / writer 14 FSK-modulates or PSK-modulates the transmission data in accordance with the upper-layer communication data S14 received from the higher-level computer 12, and transmits the transmission electromagnetic wave S6 to the non-contact IC card 13, thereby transmitting the non-contact IC card. The received electromagnetic wave S9 received from the PSK is demodulated, and the host computer 1
2 is configured to send to.

For example, in the data selector 4, the select signal S4 has 2 bits (B0 and B1) as shown in FIG. 2, and the transmission signal S5 is either PSK or FSK according to a command from the controller 3 or a switch from the host computer 12. B1 showing the difference (PSK when B1 is 0, FS when 1)
K) is designated, and in the case of PSK (B1 = 0), the PSK transmission data of S8 is selected in S5, and in the case of FSK (B1
= 1), the bit of the FSK transmission data is set to B0.
Enter FSK (B1 = 1) and send bit is 1
If S2 is selected, S2 is selected, and if the transmission bit is 0, S5 is selected S3.

FIG. 2 is a waveform diagram for explaining that the non-contact IC card reader / writer 14 PSK-modulates the transmission data S7. In FIG. 2, the reference signal S
2 is generated from the reference signal S1 by the frequency divider 2. For example, if the transmission frequency is 125 KHz, the reference signal 1 is created at 125 KHz, and the frequency of the transmission data S7 is generally 1/16 or 1/8 or 1 / the transmission frequency.
Set to 4. Fig. 2 shows the case of 1/4 and the transmission data is 3
It becomes 1.25 KHz (31.25 Kbps). When the transmission data S7 changes as shown in FIG. 2, the first exclusive OR calculator 7 executes an exclusive logical operation (Exclusive Or) of the transmission data S7 and the reference signal 1,
It becomes like the PSK transmission data S8-9. Further, at this time, the controller 3 causes the data selector 4 to send the PSK transmission data S8.
The selector signal S4 is sent so as to select -9, and the data selector 4 outputs the PSK transmission data signal S8-9 as the transmission signal S5-9. This transmission signal S5 is power-amplified by the transmission amplifier 5, and is transmitted from the transmission antenna 6 to P as shown in FIG.
It is output as a SK-modulated transmission electromagnetic wave.

Next, FIG. 3 shows a waveform diagram for explaining that the non-contact IC card reader / writer 14 performs FSK modulation. In FIG. 3, reference signal 1S2 and reference signal S
3 is generated from the reference signal S1 by the frequency divider 2. In FIG. 3, the reference frequency is 125 KHz, the reference signal S2 is used, and the normal reference signal S3 is 110 KHz to 120 KHz.
It was set to 5 KHz. The controller 3 transmits a transmission signal (“0” or “1”) desired to be FSK modulated as the select signal 4, and the data selector 4 transmits the reference signal S2 when the selector signal is 1 and the reference signal 2 when the selector signal is 0. Output as signal S5. In FIG. 3, this is the reference signal 2 when the select signal is "0" and the reference signal 1 when it is "1" like the FSK transmission data. This transmission signal S5 is power-amplified by the transmission amplifier 5 and is transmitted from the transmission antenna 6 to F as shown in FIG.
It is output as a SK-modulated transmission electromagnetic wave. That is, the data selector 4 also serves as a PSK / FSK switch and a frequency switch for FSK modulation.

Next, a waveform diagram for explaining that the non-contact IC card reader / writer 14 performs PSK demodulation is shown in FIG. FIG. 4 shows an example in which the received electromagnetic wave is 62.5 KHz and the data is 1/4 and 15.625 KHz (Kbps). When the reception electromagnetic wave S9 enters the reception antenna 8, is amplified by the reception amplifier 9, and is binarized (digitized), PSK
It becomes like the waveform of the reception data S10. This PSK reception data S10 is held by the shift register 10 for one bit of data. Normally, the PSK received data is shifted eight times in one cycle and holds the data. Therefore, the shift register 10 requires 32 bits, which is eight times as many as four pulses.
1) requires 500 KHz, which is 8 times 62.5 KHz. The shift register uses PSK received data for 4 cycles (received data is 1 bit) old data for 1 bit before data S
Output as 12. In the figure, the right side is old in time, so PS
It is 1 that the waveform of K reception data S10 is shifted to the right by 4 cycles.
It becomes the pre-bit data S12. This PSK reception data S
12 and the 1-bit previous data S12 by the second exclusive OR calculator 11 to perform an exclusive OR operation (ExclusiveO).
r), it becomes the reception data S13. That is, P is calculated by calculating whether there is a change in the data one bit before.
It is SK modulated. Here, the shift register 10 and the second
Together with the exclusive OR calculator 11 of FIG. The controller 3 receives the reception data S13 and sends it to the host computer 12 as host communication data S14. In the present embodiment, the transmitting antenna and the receiving antenna have different configurations, but when transmitting and receiving do not occur simultaneously, it is possible to switch and use one antenna.

[0020]

[0021]

According to the present invention, the modulator of the first means is configured as a PSK modulator for performing PSK modulation by performing an exclusive OR operation on the reference signal and the transmission data divided by the divider. Thus, the PSK modulator has an excellent effect that it is simple and does not increase the cost.

[0022]

Further, according to the present invention, the demodulator is configured as a PSK demodulator that performs an exclusive OR operation on the currently received data and the data received one bit before to perform PSK demodulation. The PSK demodulator has an excellent effect that it is simple and does not increase the cost.

[Brief description of drawings]

FIG. 1 is a block diagram of a reader / writer device for a non-contact IC card according to an embodiment of the present invention.

FIG. 2 is an explanatory view of a modulation method of PSK modulation and FSK modulation.

FIG. 3 is a waveform chart for explaining that the non-contact IC card reader / writer PSK-modulates transmission data in the same embodiment.

FIG. 4 is a waveform diagram for explaining that the reader / writer for the non-contact IC card performs FSK modulation in the same embodiment.

FIG. 5 is a waveform diagram for explaining that the reader / writer for the non-contact IC card performs PSK demodulation in the same embodiment.

FIG. 6 is a block diagram of a conventional non-contact IC card reader / writer device.

FIG. 7 is a waveform diagram for explaining a modulation method of a non-contact IC card.

[Explanation of symbols]

1 Reference signal source 2 frequency divider 6 transmitting antenna 8 receiving antenna 14 Reader / writer for non-contact IC card

Continuation of the front page (56) Reference JP-A-8-241383 (JP, A) JP-A-5-210768 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G06K 17 / 00 G06K 19/07-19/077

Claims (2)

(57) [Claims] 1. A reference signal source for generating a reference signal of a constant frequency, a frequency divider for dividing the reference signal generated by the reference source, an antenna for transmitting and receiving electromagnetic waves to and from a non-contact IC card, and a transmitter. A modulator that modulates data by the first modulation method or the second modulation method and transmits to the antenna, and switches between the first modulation method and the second modulation method. A switch,
A demodulator for demodulating the data received from the antenna is provided , and the reference signal and the transmission data divided by the divider are provided .
A card reader device which performs an exclusive OR operation and modulates by the first modulation method . 2. A reference for generating a reference signal having a constant frequency.
A signal source and a component for dividing the reference signal generated by the reference source.
An antenna that sends and receives electromagnetic waves to and from a frequency-contactless IC card
Modulates the tena and the transmission data by the first modulation method
Alternatively, the antenna is modulated by a second modulation method.
For transmitting to the first, the first modulation method and the second
A switching device that switches which of the modulation methods is used,
A demodulator for demodulating the data received from the antenna
Provided by the currently received data and the shift register.
Exclusive OR operation with the data received one bit before
And demodulate the signal modulated by the first modulation method.
Card reader device.