JP3350226B2 - Data transfer receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for transferring data between devices used in small portable information devices such as wireless handy terminals.

[0002]

2. Description of the Related Art Conventionally, a proximity data transfer technique used in a small portable information terminal device or the like utilizes an electromagnetic induction phenomenon generated between electromagnetic coils in a data transmitting / receiving section. This electromagnetic induction can be explained by the correlation between the electric field E and the magnetic field H given by the following equation (ie, Maxwell's electromagnetic equation).

Rot E = −μdH / dt (1) rot H = −εdE / dt (2) In (1) and (2), μ and ε are magnetic permeability and dielectric constant, respectively, and t is time.

FIG. 1 is a conceptual diagram of conventional proximity data transfer using an electromagnetic coil in a transmitting / receiving section. When an alternating current 26 containing data information is input to an electromagnetic coil 25 of a transmitting section 24, an alternating magnetic field H is generated. At the same time, an induction electric field E is also generated according to (1). That is, when the alternating current 26 is input to the electromagnetic coil 25 of the transmission unit 24, according to (1), an electromagnetic wave 27 having the magnetic field B and the induction electric field E as components is generated in the space by using the transmission unit electromagnetic coil 25 as a generation source. Radiated. When the spatially radiated electromagnetic wave 27 is detected by the electromagnetic coil 29 of the receiving unit 28, (1) and (2)
An induced current I30 and an induced magnetic field are generated in the electromagnetic coil 29 of the receiving unit 28. By detecting this induced current I30,
The data information on the transmitting side can be transferred to the receiving side. The above is the outline of the proximity data transfer technology using electromagnetic induction. Although this proximity data transfer technology is inferior in terms of transfer speed and transfer distance as compared with wireless communication technologies such as mobile phones (car phones) and radios, it is a technology that is widely used due to the simplicity of the circuit configuration. is there.

[0005]

Normally, a small portable wireless terminal device is required to have both functions of wireless communication with a base unit and data transfer between terminals. This data transfer is performed within a few centimeters or in the state of contact between terminals,
There is a need for an electromagnetic induction system using the above-described electromagnetic coil. Therefore, a small portable wireless terminal device is a relatively simple data transmission / reception device that transmits and receives radio waves of several tens of MHz to several GHz for wireless communication (hereinafter simply referred to as an RF circuit, which performs proximity data transfer by an electromagnetic induction method). A circuit section (hereinafter abbreviated as an electromagnetic induction circuit) is built in. The induction current I generated in the electromagnetic coil on the receiving side of the electromagnetic induction circuit is transferred as apparent from the equations (1) and (2). This has the property of increasing in proportion to the frequency of the signal to be transmitted, so that sufficient reception sensitivity can be obtained in the region where the frequency of the transfer signal is high, but poor sensitivity occurs at low frequencies.

That is, in a data transfer system using an ordinary electromagnetic induction coil, there is a serious drawback that only high-frequency signals can be transferred. In particular, it was not an exaggeration to say that it was almost impossible for low-frequency signals of several tens Hz or less. Due to this drawback, in a proximity data transfer system such as a small portable wireless terminal, it becomes necessary to increase the frequency of a transfer signal in order to increase the reception sensitivity, and the power consumption of this electromagnetic induction circuit is inevitably high. This is a major problem in product design.

[0007] The above-described problems are inherently inevitable in systems using electromagnetic induction. In order to avoid the above problem, there is an attempt to solve the problem by using an amorphous magnetic impedance element in a data receiving circuit. This amorphous magnetic impedance element (hereinafter, abbreviated as MI element) is a bulk or film element that has recently attracted attention as a high-sensitivity magnetic sensor element, and a magnetic field is applied while an alternating current is applied. And an element in which the impedance component of the element greatly changes (for example, Magnetics Research Institute Material No. M
AG-93-99 "Amorphous MI device FET200
MHz sensor function oscillator ”: IEEJ). As shown in FIG. 7, the electrical equivalent circuit of this MI element is made up of a real resistance component Rs and an inductance component Ls, and both or one of Rs and Ls greatly changes when a magnetic field is applied. . Further, this MI element has the following significant features.

Feature (1) The impedance change with respect to the applied magnetic field is highly sensitive and has a sensitivity of 0.1 Gauss or less. Characteristic (2) Detectable from a static magnetic field to a high-frequency magnetic field of about 10 MHz. Feature (3) It can be processed into an ultra-small shape with a length of 1 mm or less and a diameter or thickness of 100 μ or less.

Characteristic (4) The electrical parameters (Rs, Ls) and the sensitivities that can be changed according to the element forming and mounting conditions can be freely selected. That is, instead of forming the data receiving circuit with an electromagnetic coil, an attempt has been made to form a receiving circuit using this MI element.

However, in the conventional method as an ultra-small magnetic sensing element, which is originally a great advantage of the MI element, an LC oscillation circuit or a crystal oscillation circuit must be assembled in order to detect a change in an external magnetic field with a magnetic sensor. Did not. For this reason, there is a problem that it becomes a significant obstacle when trying to reduce the size and the current consumption of the device.

[0011]

Therefore, according to the present invention, a high-frequency current obtained by dividing a high-frequency output of a local oscillation circuit of a receiving unit for performing data communication using ordinary electromagnetic waves is used for driving a magnetic sensor. By generating a circumferential magnetic field in the magnetic sensor using the high-frequency current, a change in the external magnetic field sensed by the magnetic sensor is detected.

[0012]

In the data transfer receiving apparatus configured as described above, the receiving section for performing data communication using ordinary electromagnetic waves divides the high frequency output of the local oscillator provided for extracting the intermediate frequency. The high-frequency current obtained is used for driving the magnetic sensor, and a circumferential magnetic field can be generated in the magnetic sensor by the high-frequency current. Therefore, in order to generate the high-frequency current required for driving the magnetic sensor, an LC oscillation circuit or a crystal oscillation circuit is used. It is not necessary to provide a circuit, so that a data transfer receiving device in which the size of the device is reduced by the amount of these oscillation circuits and the current consumption is reduced can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram of the data transfer receiving device according to the present invention. In FIG. 2, in a receiving unit that performs data communication using electromagnetic waves, a signal obtained by amplifying a reception signal received by the antenna 1 by a high frequency amplifier circuit 2 and a high frequency generated by a local oscillation circuit 4 are mixed by a frequency mixer 3. Then, the intermediate frequency is amplified by an intermediate frequency amplifier circuit 5 and demodulated by a demodulation circuit 6 to obtain a data output.

On the other hand, in communication using an oscillating magnetic field, a high-frequency current generated by the local oscillation circuit 4 is frequency-divided by a frequency dividing circuit 7 and applied to the MI element 8 as a high-frequency current of an appropriate frequency. This high-frequency current generates a circumferential AC magnetic field in the MI element 8, and an AC voltage is generated at both ends of the MI element 8. Here, when an external magnetic field is applied in the length direction of the MI element 8, the magnetization vector of the circumferential magnetic field rotates, and the magnetic permeability in the circumferential direction decreases by the cosine in the direction of the rotation. As a result, the amplitude of the AC voltage at both ends of the MI element 2 decreases. According to this principle, the fluctuation of the external magnetic field sensed in the MI element 2 can be converted into the fluctuation of the current amplitude. The signal wave thus obtained is amplified by the amplifier circuit 9 and the demodulation circuit 10
And demodulate to obtain a data output.

[0015]

As described above, according to the present invention, in the data transfer receiving apparatus configured as described above, the high frequency output of the local oscillation circuit of the receiving section for performing data communication using ordinary electromagnetic waves is divided. The obtained high-frequency current is used for driving a magnetic sensor, and there is no need to provide an LC oscillation circuit or a crystal oscillation circuit to generate the high-frequency current required for driving the magnetic sensor. There is an effect that it is possible to obtain a data transfer receiving device with reduced power consumption.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and is a block diagram showing a configuration of a receiving section circuit of a data transfer system according to the present invention.

FIG. 2 is a conceptual diagram showing a conventional proximity data transfer using electromagnetic induction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna 2 High frequency amplifier circuit 3 Frequency mixer 4 Local oscillator circuit 5 Intermediate frequency amplifier circuit 6 Demodulator circuit 7 Divider circuit 8 MI element 9 Amplifier circuit 10 Demodulator circuit 24 Transmitter 25 Electromagnetic coil 26 AC current 27 Electromagnetic wave 28 Receiver 29 Electromagnetic coil 30 Induction current I

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshio Inakoshi 6-31-1, Kameido, Koto-ku, Tokyo Inside Seiko Electronic Industries Co., Ltd. (72) Inventor Seiji Kuwahara 6-31, Kameido, Koto-ku, Tokyo No. Seiko Electronics Co., Ltd. (72) Inventor Hitoshi Yoshida 6-31-1, Kameido, Koto-ku, Tokyo Seiko Electronics Co., Ltd. (56) References JP-A-8-30923 (JP, A) Kaihei 4-137620 (JP, U) JP-A-1-98876 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04B 5/00-5/02 G06F 13/00 351 G06F 15/02 335 G01R 33/00

Claims (1)

(57) [Claims] 1. A small-sized portable data transfer receiving device that performs data transfer between terminals by an oscillating magnetic field in addition to data transfer by normal wireless communication, a receiving unit that receives and demodulates an electromagnetic wave modulated by data, The proximity data communication method using an oscillating magnetic field has a bulk or film-shaped amorphous magnetic sensor element whose impedance value changes according to an external magnetic field, and outputs an output of a local oscillation circuit of the receiving unit to the magnetic field. A data transfer receiving device used for detecting a change in a magnetic field sensed by a sensor element.