JP2003244014A - Mobile terminal - Google Patents

Abstract

(57) [Summary] A portable terminal having an IC card function is provided. A mobile terminal includes a mobile communication unit having a function of a mobile communication terminal and an IC card communication unit having a function of an IC card, and the IC card communication unit communicates with a reader / writer for an IC card. It has a receiving unit and a transmitting unit for communicating by wireless communication in between. The transmitting unit of the IC card communication unit transmits an amplitude modulation (ASK) transmission signal that generates a function equivalent to load modulation in order to activate the load switch detection unit of the IC card reader / writer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile terminal such as a cellular communication terminal, and more particularly to a multifunctional mobile terminal.

[0002]

2. Description of the Related Art In recent years, mobile phones, PHS (Personal Ha
ndyphone System), PDA (Personal Digital Ass)
Information communication terminal devices such as an instance) have spread, and these communication terminal devices have various functions as well as a call function. Such additional functions include a data communication function for communicating information via an information communication network such as the Internet, a position detection function using GPS (Global Positioning System), and the like.

On the other hand, IC cards for conducting electronic transactions are widely used. An IC card is a plastic card with an IC (Integrated Circuit) embedded in it. It has a larger storage capacity than a magnetic card and is used as a cash card, credit card, debit card, electronic money, etc. with an authentication function. be able to.

There are contact type and non-contact type IC cards.
Since neither has a built-in battery, power is obtained from the outside. In the contact type, the terminals exposed on the edge of the card are brought into contact with the terminals of the IC card reader / writer to communicate power and signals. The non-contact type IC card has an antenna coil built therein, and communicates power and a signal by electromagnetic coupling with the antenna coil of the IC card reader / writer. This utilizes the principle of a transformer, and
The coil of the card reader / writer and the coil of the IC card correspond to the primary coil and the secondary coil of the transformer.

In the transmission from the IC card reader / writer to the non-contact type IC card, that is, in the downstream communication, an induced current is induced in the IC card coil by changing the carrier magnetic field generated by the IC card reader / writer coil. To generate. Data can be obtained by detecting the change in the induced current.

In transmission from a non-contact type IC card to an IC card reader / writer, that is, in upstream communication, the load of the coil of the IC card is changed to change the current flowing in the coil of the IC card reader / writer. . This is referred to as load switch (load switch) or load modulation (load modulation). At this time, the magnetic field generated by the coil of the IC card reader / writer is kept constant.

In the communication between the non-contact type IC card and the IC card reader / writer, the carrier of the same frequency is used in the downlink communication and the uplink communication. Carrier modulation methods include direct modulation using only carriers and methods using carriers and subcarriers. The modulation method is
Amplitude Shift Keying (ASK) is used. ASK100% modulation and ASK10 for amplitude modulation
There is% modulation. In the case of ASK 100% modulation, the amplitude magnitude is zero during the off period of the modulation signal, and 100% during the on period. In the case of ASK 10% modulation, the amplitude magnitude is 90 when the modulation signal is off.
%, And the magnitude of the amplitude is 100% during the ON period.

With ASK 100% modulation, there are no carriers in the off period. Therefore, a method using carriers and subcarriers is used so that the period in which no carrier exists is shortened. On the other hand, with ASK 10% modulation, 90% amplitude is obtained even in the off period, so 90% power is guaranteed. Therefore, a direct modulation scheme with data rate is also used.

[0009]

The contact type IC card is
At the time of use, it has to be brought into contact with the IC card reader / writer, and the operation is not easy. Non-contact type IC card is I
It is not necessary to contact the reader / writer for C card, but I
The C-card reader / writer must be brought close to a predetermined distance, which limits its intended use.

It is an object of the present invention to expand the usage of IC cards so that they can be used in various fields and applications.

An object of the present invention is to provide not only a telephone function but also a cash card function, a credit card function, a debit card function, and the like as functions of a mobile terminal.

[0012]

According to the present invention, a portable terminal has a mobile communication section having the function of a mobile communication terminal and an IC card communication section having the function of an IC card. Has a receiving unit and a transmitting unit for communicating by wireless communication with the IC card reader / writer. The transmission unit of the IC card communication unit transmits a transmission signal that is a waveform that generates a function equivalent to load modulation. The transmission carrier of the transmission signal has a phase that decreases or increases the amplitude of the reception carrier of the amplitude modulation type reception signal received from the IC card reader / writer when the load switch is turned on in the IC card reader / writer. Have. The transmission carrier of the transmission signal is
When the load switch is turned on in the IC card reader / writer, it has an opposite phase with respect to the reception carrier of the amplitude modulation type reception signal received from the IC card reader / writer.

Therefore, according to the present invention, the portable terminal is an IC
Since it is possible to communicate with the IC card reader / writer like a card, the function of the IC card can be provided.

According to the present invention, the receiving section has a reception amplification circuit with an automatic gain control function. The reception amplification circuit has a function of stopping the automatic gain control operation while the transmission section is transmitting a transmission signal and maintaining the state immediately before the stop.

According to the present invention, the IC card communication section has a logical clock generation section for generating a logical operation clock from a received signal and a transmission clock generation section for generating a transmission clock, and the transmission is performed. The clock generation unit has a function of stopping the operation when the logic operation clock is not generated and maintaining the state immediately before the stop. The transmission clock generation unit includes a phase comparator that uses the logical operation clock as a reference frequency, a charge pump, and a voltage controlled oscillator, and when the logical operation clock is not generated, the phase comparator and the charge pump. Of the voltage-controlled oscillator is maintained and the state immediately before the voltage-controlled oscillator is stopped is maintained.

According to the present invention, the function of the transmission clock generation unit for maintaining the state immediately before the stop is activated while the transmission signal is generated by the transmission unit.

According to the present invention, the IC card communication section has a pause detection circuit for detecting a pause period corresponding to OFF in the binary value of the amplitude of the received signal of the amplitude modulation system, and the transmission clock is generated. In the pause period output from the pause detection circuit, the section operates to maintain the state immediately before the stop.

According to the present invention, the IC card communication unit has a damping signal generation circuit for generating a damping signal for damping the vibration of the transmission signal after the end. The function of the transmission clock generation unit to maintain the state immediately before the stop for a predetermined period after the damping signal is generated by the damping signal generation circuit operates.

Therefore, it is possible to stably read the data from the received signal from the IC card reader / writer.

According to the present invention, the transmission section has a transmission amplification circuit for generating a transmission signal, and the transmission amplification circuit inputs the reception radio wave intensity signal representing the amplitude of the reception signal from the reception section, It has an automatic gain control function for controlling the magnitude of the amplitude of the transmission signal based on the received radio field intensity signal.

Therefore, the strength of the transmission signal can be set to an optimum value, stable upstream communication can be performed, and power consumption can be prevented.

According to the present invention, the IC card communication unit includes a receiving antenna coil for receiving a reception signal from the IC card reader / writer and a transmission antenna coil for transmitting a transmission signal to the IC card reader / writer. And. The reception antenna coil and the transmission antenna coil are arranged such that, of the magnetic fluxes generated by the transmission antenna coil, the magnetic fluxes passing through the reception antenna coil in mutually opposite directions cancel each other out.

Therefore, the reception signal received by the reception antenna coil does not include noise caused by the signal transmitted by the transmission antenna coil.

According to the present invention, the IC card communication unit is connected to the transmission / reception antenna coil for transmitting / receiving signals to / from the IC card reader / writer, the transmission unit connected to the transmission / reception antenna coil, and the transmission / reception antenna coil. And a receiver having a variable input attenuator.

Therefore, there is an advantage that the received data can be obtained even if the strength of the received signal is small.

According to the present invention, the IC card communication section is powered by a battery. Therefore, the desired amplification effect can be obtained in the amplifier, and the communication range of the IC card communication unit can be increased.

According to the present invention, the IC card reader / writer has the antenna coil of the IC card reader / writer, the detection circuit for detecting the amplitude of the received signal from the antenna coil, and the amplification of the output of the detection circuit. Reception amplification circuit, a waveform shaping circuit for shaping the signal waveform output from the reception amplification circuit, a demodulation circuit for demodulating the output of the waveform shaping circuit into a data signal, and a data signal from the demodulation circuit And a drive circuit for generating an antenna drive signal from the transmission signal from the modulation circuit and a modulation circuit for modulating transmission data into a transmission carrier signal. It has an automatic gain control function for controlling the strength of the received signal to an appropriate value.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the present invention will be described with reference to FIG. The mobile terminal 1 of this example includes an IC card communication unit 2, a mobile communication unit 3, and a mobile terminal control unit 4. The IC card communication unit 2 includes a normal non-contact type IC card reader / writer 5
It is configured so as to be able to communicate with, and provides a function equivalent to a normal IC card. The mobile communication unit 3 has the same function as a normal mobile terminal, and may be any mobile terminal device having a call function, a data communication processing function, and an information processing function, such as a mobile phone, a PHS (personal handy phone system), a PDA. (Personal Digital Assistant), car phone, etc.

Communication between the IC card communication unit 2 and the non-contact type IC card reader / writer 5 will be described. As described above, the IC card reader / writer 5 communicates power and signals with the non-contact type IC card by electromagnetic coupling. In downlink communication, a carrier magnetic field is generated in the coil of the IC card reader / writer 5. In upstream communication, load modulation (load modulation) is applied to the antenna coil of the IC card in order to operate the load switch (load switch) detection unit of the IC card reader / writer 5.

On the other hand, in this example, instead of electromagnetic coupling, a radio signal is used for communication between the IC card communication section 2 and the non-contact type IC card reader / writer 5. In downlink communication, the IC card communication unit 2 receives a radio signal transmitted from the antenna coil of the IC card reader / writer 5. In upstream communication, the IC card communication unit 2 transmits a wireless signal to activate the load switch (load switch) detection unit of the IC card reader / writer 5. With this radio signal, the load switch detection unit of the IC card reader / writer 5 performs load modulation (load modulation).
The same operation is performed when a signal is received.

Communication between the IC card reader / writer 5 and the IC card communication unit 2 may be based on ISO14443, for example. ISO14443 defines a communication protocol between a non-contact type IC card and an IC card reader / writer.

Transmission from the IC card reader / writer 5 to the IC card communication unit 2, that is, downlink communication will be described with reference to FIG. For downlink communication, a direct modulation method that does not use subcarriers is used. FIG. 8A shows an example of data received by the IC card communication unit 2 from the IC card reader / writer 5, and FIG. 8B shows an example of a modulation signal for this received data. As shown, start frame, 1,
0, stop frame, are modulated signals C, A,
It is modulated into B and C. Each modulated signal A, B, C is generated by a combination of ON and OFF as shown. Figure 8
C is an enlarged view of the modulation signal C. As shown, the ON portion of the received modulated signal is composed of the 13.56 MHz received carrier signal. The received modulated signal is 13.56
It is generated by a combination of ON with the reception carrier of MHz present and OFF without the reception carrier. As shown in FIG. 8D, the period in which the received carrier signal does not exist, that is, the OFF portion of the received modulated signal is referred to as a pause period here. The pause period will be described later. here,
The case where 100% ASK modulation is used has been described, but 10
% ASK modulation may be used. In the case of 10% ASK modulation, the amplitude is 90% even in the off part of the received modulation signal.
Since there is a reception carrier of, the power is always supplied and the clock for logical operation can be generated.

Transmission from the IC card communication unit 2 to the IC card reader / writer 5, that is, upstream communication will be described with reference to FIG. A method using subcarriers is used for upstream communication. FIG. 9A shows the IC from the IC card communication unit 2.
An example of data transmitted to the card reader / writer 5 is shown below.
FIG. 9B shows an example of a coded waveform for this transmission data. In this example, a Manchester code having no DC component is used. FIG. 9C shows a modulation waveform with respect to a coded waveform. The transmission modulation signal is generated by a combination of a period in which subcarriers exist and a period in which subcarriers do not exist as illustrated. The transmission modulation signal is on during the period when the subcarrier does not exist. The subcarrier frequency is 847.5 KHz, which is 1/16 of the carrier frequency. Figure 9D
[Fig. 4] is an enlarged view of a transmission modulation signal. As shown in the figure, the portion where the transmission modulation signal is on, that is, the portion where the subcarrier is on and the portion where the subcarrier does not exist are 13.56 MH
z transmit carrier. FIG. 9E shows 13.56
It is an enlarged view of a transmission carrier of MHz. The damping signal of FIG. 9F will be described later.

In the case of transmission from the IC card communication unit 2 to the IC card reader / writer 5, that is, in the case of upstream communication, the transmission signal generated by the IC card communication unit 2 is sent to the load switch detection unit of the IC card reader / writer. On the other hand, the operation equivalent to the load modulation signal is activated. The transmission carrier is transmitted in a state of being phase-shifted so as to cancel the reception carrier when the load switch corresponds to ON. Preferably, the transmission carrier is
When the load switch corresponds to the ON state, the phase is shifted by 180 degrees from the phase of the reception carrier, and transmission is performed. As a result, the load switch detection unit of the IC card reader / writer performs the same operation as when the load modulation signal is received.

A configuration example of the IC card communication unit 2 will be described with reference to FIG. The IC card communication unit 2 is a receiving antenna 1 for receiving a signal from the IC card reader / writer 5.
1 and a transmission antenna 21 for transmitting a signal to the IC card reader / writer 5, a reception circuit 10, a transmission circuit 20, a logical clock generation circuit 31, a pause signal generation circuit 32, an AGC signal generation circuit 33, and a transmission clock generation circuit 35. And a signal processing circuit 40.

Although the IC card communication unit 2 further has a memory not shown, the memory of the mobile communication unit 3 may be used instead of this memory. The power supply voltage Vdd used for the IC card communication unit 2 may be supplied from the power supply unit of the mobile communication unit 3, but preferably the power supply battery included in the IC card communication unit 2 itself is used. By using the power supply battery provided in the IC card communication unit 2, the amplification circuit of the IC card communication unit 2 can provide a desired amplification function, so that the communication distance of the IC card communication unit 2 is increased. You can

The reception circuit 10 is a reception amplification circuit 1 with an automatic gain control function for amplifying a reception signal from the reception antenna 11.
2, a detection circuit 13 for detecting the envelope of the amplitude of the output of the reception amplification circuit, a waveform shaping circuit 14 for shaping the signal output from the detection circuit into a rectangular wave, and the output of the waveform shaping circuit as a data signal. And a demodulation circuit 15 for demodulation. The transmission circuit 20 has a modulation circuit 23 for modulating transmission data into a transmission carrier signal and a transmission amplification circuit 22 with an automatic gain control function for amplifying the transmission signal from the modulation circuit 23.

According to this example, the reception amplification circuit 12 has an automatic gain control (AGC) function and the AGC signal generation circuit 33.
The amplification gain is automatically adjusted by the AGC signal generated by. Therefore, the amplitude of the reception signal output from the reception amplification circuit 12 is always held at a constant value or range regardless of the strength of the reception signal.

According to this example, the reception amplification circuit 12 has a freeze function of stopping the amplification variable function and maintaining the immediately previous state. The freeze function operates during transmission, that is, while the transmission signal is being generated by the transmission circuit 20.
During transmission, the transmission signal output from the transmission antenna 21 is also received by the reception antenna 11. Therefore,
When the reception amplification circuit 12 is operating, the reception amplification circuit 12
Causes a malfunction. In this example, malfunction is prevented by stopping the operation of the reception amplification circuit 12 during transmission.

The logical clock generating circuit 31 receives the received signal output from the receiving amplifier circuit 12, divides the frequency of the received carrier signal, and generates a logical operation clock. The logical operation clock output from the logical clock generation circuit 31 is used for logical operation, data demodulation, and the like.

The pause signal generation circuit 32 is the reception amplification circuit 1
The received signal output from 2 is input and the pause period is detected. A pause signal indicating a pause period is supplied to the transmission clock generation circuit 35. As described with reference to FIG. 8D, the pause period is when the modulation waveform is off while the reception signal is being received. When the modulation waveform is off, there is no received carrier in 100% ASK modulation. In the 10% ASK modulation, there is a reception carrier with an amplitude of 90% even when the modulation waveform is off. The pause signal is also supplied to the logic clock generation circuit 31. During the pause period, the unstable clock signal output from the logic clock generation circuit 31 is masked and stabilized.

The transmission clock generation circuit 35 generates a clock for generating the transmission carrier of the transmission signal. The transmission clock generation circuit of this example will be described in detail later,
It includes a PLL (phase locked loop) circuit. The phase comparison circuit of the PLL circuit uses the clock from the logical clock generation circuit 31 as the reference frequency. If the phase comparator operates when the logic clock generation circuit 31 is not generating a clock, an error signal is generated and the PLL circuit does not generate a correct oscillation frequency. Therefore, when no clock is output from the logical clock generation circuit 31,
A freeze function is provided for stopping the operation of the phase comparator and maintaining the state immediately before the stop. The freeze function of the transmission clock generation circuit 35 of this example operates in the following three cases. (1) When a transmission signal is generated (2) When a pause signal exists, that is, a pause period (3) Damping period

First, when the transmission signal is being generated,
The logical clock generation circuit 31 does not generate a clock. Uplink communication and downlink communication are alternately performed in a time division manner. Therefore, no reception signal is received during the transmission period. Further, during transmission, as described above, the reception amplification circuit 12 does not operate due to the freeze function. Therefore, during the transmission period, since there is no reception carrier, the logical clock generation circuit 31 does not generate a clock.

Next, even during reception, during the pause period, as described above, there is no reception carrier. Therefore, the logical clock generation circuit 31 does not generate a clock. With 10% ASK modulation, even during the pause period, 90
There are% carrier amplitudes received.

Therefore, in the case of 10% ASK modulation, the operation of the transmission clock generation circuit 35 may be continued without being frozen even during the pause period.

Next, the damping signal and the damping period will be described with reference to FIG. FIG. 10A is an enlarged view of the transmission carrier waveform, and FIG. 10B shows a damping signal whose phase is delayed by 90 degrees from the end of the transmission carrier waveform, and correspond to FIGS. 9D and 9E. FIG. 10C shows a transmission signal transmitted from the transmission antenna 21. As shown by the broken line, even if the transmission carrier signal ends, in reality, the transmission signal does not immediately become zero, but an attenuated waveform remains. The operation of the reception amplification circuit 12 cannot be started while the decay waveform remains.

A damping signal is used to cancel the attenuation component of the transmitted signal. The damping signal is generated at the zero cross point of the transmission signal as shown in the figure. This zero-cross point has a phase delay of 90 degrees from the end of the transmission carrier signal. The damping period is a period from the generation of the damping signal to the elimination of the attenuated portion and the complete absence of the transmission carrier signal, which is determined by experiment. The reception amplification circuit 12 does not operate during the damping period. Therefore, since there is no reception carrier, the operation of the transmission clock generation circuit 35 is frozen.

Next, the automatic gain control function of the transmission amplifier circuit 22 will be described. The transmission amplification circuit 22 is configured to automatically adjust the amplification gain so that the intensity of the transmission signal from the transmission antenna 21 has an optimum value or range. The optimum value of the strength of the transmission signal is determined by the distance between the IC card communication unit 2 and the IC card reader / writer 5. That is, if the distance between the two is large, the strength of the transmission signal is large, and if the distance between the two is small, the strength of the transmission signal may be small.

The AGC signal generation circuit 33 generates an AGC signal from the output of the reception amplification circuit 12 and feeds it back to the reception amplification circuit 12. The reception amplification circuit 12 is
Automatic gain control is performed by the AGC signal, and further IC
A signal indicating the distance between the card communication unit 2 and the IC card reader / writer 5 is generated and supplied to the transmission amplification circuit 22. The transmission amplification circuit 22 adjusts the strength or amplitude of the transmission signal based on the distance signal supplied from the reception amplification circuit 12.

An example of the reception amplification circuit 12 will be described with reference to FIG. The reception amplification circuit 12 of this example includes a reception antenna 11
The operational amplifier circuit 121 that differentially amplifies the received signals LA and LB obtained by the above, the variable attenuator 122 for automatic gain control, and the AGC signal supplied from the AGC signal generation circuit 33.
A / D conversion of signals to digital signals AGCAD1 and AGC
And an AD conversion circuit 123 for obtaining AD0. The variable attenuator 122 includes a MOS transistor, and its gate is supplied with the AGC signal. The AGC signal adjusts the overall gain including the amplifier 121. I
When the distance between the C card communication unit 2 and the receiving antenna 11 is short, a deep bias is applied to the MOS transistor and the ON state becomes strong. On the contrary, when the distance is long, the bias becomes shallow and the off state occurs. This function makes the amplifier 1
Excessive input to 21 is suppressed and normal amplification is possible.

Output signal AGCAD of the AD conversion circuit 123
As described above, 1 and AGCAD0 indicate the distance between the IC card communication unit 2 and the IC card reader / writer 5, and are supplied to the transmission amplification circuit 22.

Referring to FIG. 4, transmission clock generation circuit 3
Example 5 will be described. The transmission circuit 35 of this example includes the PLL circuit as described above. This PLL circuit includes a phase comparator 35.
1, a charge pump 352, and a voltage controlled oscillator 353. The transmission clock generation circuit 35 of this example has a freeze function. An OR circuit 354 for supplying a pause signal, a damping signal or a transmission signal is provided on the input side of the phase comparator 351 and the charge pump 352. When any of the transmission signal, the pause signal, and the damping signal is present, the phase comparator 351 and the charge pump 352 stop their operations and maintain the immediately preceding state. The charge pump 352 is a current drive type and provides a hold function. The suspension period of the comparison operation by the phase comparator 351 is until the time when the normal generation of the reception clock is started, but it is determined by an experiment.

The transmission clock generation circuit 35 further includes 1
A 1/2 frequency divider 355 is provided. As described with reference to FIG. 9, the damping signal has a phase delay of 90 degrees from the transmission carrier. The output SCK of the 1/2 frequency divider 355 is
Used to generate a damping signal.

Referring to FIG. 5, logical clock generation circuit 3
1. Pause signal generation circuit 32 and AGC signal generation circuit 3
Example 3 will be described. Logical clock generation circuit 31 of this example
Generates a clock signal from the differential output from the reception amplification circuit 12 by a zero cross comparator. The pause signal generation circuit 32 of this example detects the differential output from the reception amplification circuit 12 by an offset comparator 321 and generates a wide pulse by the one-shot circuit 322, and uses this wide pulse and a clock signal to pause. Generate a signal. The AGC signal generation circuit 33 includes a MOS transistor and is obtained by sampling and holding the envelope-detected waveform with the carrier signal detected by the comparator with offset.

Referring to FIGS. 6 and 7, the transmission amplifier circuit 22
An example will be described. As shown in FIG. 6, the transmission circuit 2 of this example
Reference numeral 2 includes an operational amplifier circuit 221 with an automatic gain control function which inputs the output signal SCK of the 1/2 frequency divider 355 and the transmission antenna drive signal DRV, and a damping circuit 222 which inputs the damping signal DUMP. FIG. 7 shows a configuration example of the operational amplifier circuit 221 with an automatic gain control function. As shown,
The operational amplification circuit 221 inputs the power supply voltage Vdd, the output signal AGC-CNT signal from the AGC signal generation circuit 33 and the transmission antenna drive signal SDRV, and automatically sets the amplification gain so that the amplitude becomes a predetermined value or range. Has the function of adjusting.

The transmitting antenna drive signal DRVOUT output from the two operational amplifier circuits 221 is the transmitting antenna 21.
Is supplied to. The antenna drive system is a differential series resonance system.

The damping circuit 222 is composed of two MOS transistors and is configured so that a damping signal is supplied to its gate. The output of the damping circuit 222 is connected to the transmission antenna 21. At the end of the transmission signal, the damping circuit 22 performs the damping operation, whereby the damping oscillation of the transmission signal is erased and the operation of the reception amplifier 12 is started quickly.

The structures of the receiving antenna 11 and the transmitting antenna 21 will be described with reference to FIG. The receiving antenna and the transmitting antenna of this example include coils 11A and 21A, and shields 11C and 21C are provided so that magnetic fields generated by the coils do not interfere with each other. A reception lead wire 11B and a transmission lead wire 21B are connected to both ends of the reception antenna coil 11A and the transmission antenna coil 21A. The coils 11A and 21A of both antennas 11 and 21 may have the same diameter.

The two antennas 11 and 21 consist of the coil 11
The magnetic fields generated by A and 21A are arranged so as not to interfere with each other. That is, the two coils 11A,
21A are arranged at an appropriate distance. As illustrated, the magnetic flux generated by the coil 21A of the transmitting antenna 21 penetrates the coil 11A of the receiving antenna 11. However, the coil 21A of the transmitting antenna 21
Among the magnetic fluxes generated by, the vectors of the magnetic flux generated inside the coil and the magnetic flux generated outside the coil are directed in opposite directions. Therefore, the distance between the two antennas 11 and 21 may be set so that the magnetic fluxes passing through the coil 11A of the receiving antenna 11 in opposite directions cancel each other.

An example of the IC card reader / writer 5 will be described with reference to FIG. The IC card reader / writer 5 of this example includes an antenna coil 51 and a detection circuit 52 for detecting an amplitude envelope of a signal received from the antenna coil 51.
A reception amplification circuit 53 with an automatic gain control function, a waveform shaping circuit 54 for shaping the signal output from the reception amplification circuit into a rectangular wave, a demodulation circuit 55 for demodulating the output of the waveform shaping circuit into a data signal, and a signal. It has a processing circuit 56, a modulation circuit 61 for modulating transmission data into a transmission carrier signal, and a drive circuit 62 for generating an antenna drive signal from the transmission signal from the modulation circuit 61.

The IC card reader / writer 5 of this example may have the same structure as the conventional IC card reader / writer except that the reception amplification circuit 53 has an automatic gain control (AGC) function.

The example of the portable terminal of this example has been described above.
It will be appreciated by those skilled in the art that the present invention is not limited to the above examples unless it exceeds the scope of the invention as claimed.

[0063]

According to the present invention, since the portable terminal has the IC card function capable of communicating with the IC card reader / writer, it is possible to use the IC card without the IC card.
There is an effect that you can receive the same service as the C card.

According to the present invention, it is possible to communicate with the IC card reader / writer by bringing the mobile terminal close to the IC card reader / writer by a predetermined distance. It is easy to use and has a wider range of use than IC cards.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a mobile terminal according to the present invention.

FIG. 2 is an explanatory diagram illustrating an example of a configuration of an IC card communication unit of the mobile terminal according to the present invention.

FIG. 3 is a diagram showing an example of a reception amplifier circuit of an IC card communication unit of the present invention.

FIG. 4 is a diagram showing an example of a transmission clock generation circuit of the IC card communication unit of the present invention.

FIG. 5 is a diagram showing an example of a logical clock generation circuit, a pause signal generation circuit, and an AGC signal generation circuit of the IC card communication unit of the present invention.

FIG. 6 is a diagram showing an example of a transmission amplifier circuit and a damping circuit of an IC card communication unit according to the present invention.

FIG. 7 is a diagram showing a part of a transmission amplifier circuit of an IC card communication unit according to the present invention.

FIG. 8 is a diagram showing an example of generation of a communication signal from the IC card reader / writer to the IC card communication unit according to the present invention.

FIG. 9 is a diagram showing an example of generation of a communication signal from an IC card communication unit according to the present invention to an IC card reader / writer.

FIG. 10 is an explanatory diagram illustrating an example of a damping signal.

FIG. 11 is an explanatory diagram illustrating an example of an antenna of an IC card communication unit according to the present invention.

FIG. 12 is an explanatory diagram illustrating an example of an IC card reader / writer according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Receiving part, 11 ... Receiving antenna, 12 ... Receiving amplifier, 13 ... Detection circuit, 14 ... Waveform shaping circuit, 1
5 ... Demodulation circuit, 21 ... Transmission antenna, 22 ... Transmission amplification circuit, 23 ... Modulation circuit, 31 ... Logical clock generation circuit, 32 ... Pause signal generation circuit, 33 ... AGC signal generation circuit, 35 ... Transmission clock generation circuit, 40 …
Signal processing circuit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04M 1/00 H04M 1/21 Z 5K027 1/02 1/725 5K067 1/21 H04B 7/26 R 1 / 725 109H H04Q 7/38 G06K 19/00 H N (72) Inventor Ryozo Yoshino 3-5-18 Kitazawa Kitazawa, Setagaya-ku, Tokyo Takayama Building Co., Ltd. Takayamauchi Co., Ltd. Nihon Telegraph and Telephone Telephone Co., Ltd. (72) Inventor Toshinori Dobashi Tosho Nobuhashi Otemachi, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Inventor Shigeru Date Chiyoda 2-3-1, Otemachi, Ward Nihon Telegraph and Telephone Corporation F term (reference) 5B035 BB09 CA12 CA22 CA23 5B058 CA15 CA17 KA40 5K011 DA11 EA03 JA01 5K012 AA01 AB03 AB12 AC06 AC0 8 AC10 BA02 5K023 AA07 MM00 MM25 5K027 AA11 BB01 HH26 MM03 5K067 AA34 BB04 BB21 EE02 EE12 EE35 KK01 KK17

Claims (18)

[Claims] 1. A mobile communication unit having a function of a mobile communication terminal and an IC card communication unit having a function of an IC card, wherein the IC card communication unit is connected to an IC card reader / writer. A mobile terminal configured to have a receiving unit and a transmitting unit for communicating by wireless communication. 2. The mobile terminal according to claim 1, wherein the transmission section of the IC card communication section transmits a transmission signal that is a waveform that generates a function equivalent to load modulation. 3. The portable terminal according to claim 2, wherein the transmission carrier of the transmission signal is an amplitude modulation type reception received from the IC card reader / writer when the load switch is turned on in the IC card reader / writer. A mobile terminal having a phase that reduces or increases the amplitude of a reception carrier of a signal. 4. The portable terminal according to claim 2, wherein the transmission carrier of the transmission signal is an amplitude modulation type reception received from the IC card reader / writer when the load switch is turned on in the IC card reader / writer. A mobile terminal having an opposite phase to a signal receiving carrier. 5. The mobile terminal according to claim 1, wherein the receiving section has a reception amplification circuit with an automatic gain control function. 6. The mobile terminal according to claim 5, wherein the reception amplification circuit has a function of stopping the automatic gain control operation while the transmission unit is transmitting a transmission signal, and maintaining the state immediately before the stop. A mobile terminal characterized by having. 7. The mobile terminal according to claim 1, wherein the IC card communication unit includes a logical clock generation unit that generates a logical operation clock from a received signal and a transmission clock generation unit that generates a transmission clock. The mobile terminal has a function of stopping the operation when the logical operation clock is not generated and maintaining the state immediately before the stop. 8. The mobile terminal according to claim 7, wherein the transmission clock generation unit includes a phase comparator using the logic operation clock as a reference frequency, a charge pump, and a voltage controlled oscillator, and the logic operation clock. Is generated, the operation of the phase comparator and the charge pump is stopped, and the voltage controlled oscillator has a function of maintaining the state immediately before the stop. 9. The mobile terminal according to claim 7, wherein the transmission clock generation unit has a function of maintaining the state immediately before the stop while the transmission signal is generated by the transmission unit. Mobile terminal. 10. The mobile terminal according to claim 7, wherein the IC card communication unit has a pause detection circuit for detecting a pause period corresponding to OFF among binary values of amplitude of a received signal of an amplitude modulation system. The mobile terminal is characterized in that the function of maintaining the state immediately before the stop is activated in the pause period output from the pause detection circuit in the transmission clock generator. 11. The mobile terminal according to claim 7, wherein the IC card communication unit has a damping signal generation circuit for generating a damping signal that attenuates the vibration of the transmission signal after the end of the transmission signal. . 12. The mobile terminal according to claim 11, wherein
The mobile terminal, wherein the function of maintaining the state immediately before the stop is activated in the transmission clock generation unit for a predetermined period after the damping signal is generated by the damping signal generation circuit. 13. The portable terminal according to claim 1, wherein the transmission section has a transmission amplification circuit for generating a transmission signal, and the transmission amplification circuit receives the radio wave intensity representing the amplitude of the reception signal from the reception section. A portable terminal having an automatic gain control function of inputting a signal and controlling the magnitude of the amplitude of a transmission signal based on the received radio field intensity signal. 14. The portable terminal according to claim 1, wherein the IC card communication unit includes a reception antenna coil for receiving a reception signal from an IC card reader / writer, and I.
A mobile terminal, comprising: a transmission antenna coil for transmitting a transmission signal to a C-card reader / writer. 15. The mobile terminal according to claim 14,
The receiving antenna coil and the transmitting antenna coil are among the magnetic flux generated by the transmitting antenna coil.
A mobile terminal, wherein the mobile terminals are arranged so that magnetic fluxes passing through the receiving antenna coil in mutually opposite directions cancel each other out. 16. The portable terminal according to claim 1, wherein the IC card communication unit includes a transmitting / receiving antenna coil for transmitting / receiving a signal to / from an IC card reader / writer, a transmitting unit connected to the transmitting / receiving antenna coil, and A mobile terminal, comprising: a receiver having a variable input attenuator connected to a transmitting / receiving antenna coil. 17. The mobile terminal according to claim 1, wherein the IC card communication unit uses a battery as a power source. 18. An antenna coil of the IC card reader / writer according to claim 1, a detection circuit for detecting the amplitude of a reception signal from the antenna coil, and a reception amplification circuit for amplifying the output of the detection circuit. A waveform shaping circuit for shaping the signal waveform output from the reception amplification circuit, a demodulation circuit for demodulating the output of the waveform shaping circuit into a data signal, and a signal processing for processing the data signal from the demodulation circuit A reception circuit, a modulation circuit for modulating transmission data into a transmission carrier signal, and a drive circuit for generating an antenna drive signal from the transmission signal from the modulation circuit. A reader / writer for an IC card, which has an automatic gain control function for controlling an appropriate value.