JP6334252B2 - Wireless communication device - Google Patents

Description

  The present invention relates to a wireless communication apparatus capable of performing a wireless communication call satisfactorily when the wireless communication apparatus is attached to a user's belt using a belt clip of the wireless communication apparatus.

  For example, in Patent Document 1, in order to provide a radiotelephone device that can detect the approach of the human body and appropriately match the impedance between the transmission circuit and the antenna, the human body detection unit detects the approach of the human body. The communication control unit controls the variable impedance matching unit based on the detection result of the human body detection unit to match the impedance between the wireless transmission / reception unit and the antenna. Therefore, transmission power is transmitted from the wireless transmission / reception unit to the antenna without being attenuated, and is efficiently radiated from the antenna as radio waves.

  Further, in Patent Document 2, a belt is used as a means for recognizing whether a portable device is carried by a person so that the portable device recognizes whether the portable device is being carried without the user of the portable device being particularly conscious. It is disclosed to provide a switch for recognizing that a belt is sandwiched between hooks.

JP 2000-286924 A JP 2000-133958 A

  Recently, portable wireless devices are often used in restaurants and hotels for transmitting service orders and the like. In that case, the user of the portable wireless device needs to release his / her hand to work. For this purpose, the portable wireless device is attached to the user's belt using the belt clip of the portable wireless device, and the wireless communication is performed using the portable wireless device. There was a problem that could not be done.

  For example, the switch of Patent Document 2 is provided in the apparatus of Patent Document 1, and it is detected using the switch that the belt is sandwiched between the belt hooks, and the impedance between the wireless transmission / reception unit and the antenna is matched. It is also possible. However, the impedance matching circuit of Patent Document 1 has a problem that the circuit configuration becomes complicated and the manufacturing cost increases. Further, when the switch of Patent Document 2 is used, there is a problem that a non-contact structure cannot be formed on the belt, and a drip-proof or waterproof structure cannot be formed.

  The object of the present invention is to solve the above-mentioned problems, have a simple circuit configuration as compared with the conventional example, and can have a non-contact structure and a drip-proof or waterproof structure with respect to the belt. An object of the present invention is to provide a wireless communication apparatus that can perform a wireless communication call favorably when the wireless communication apparatus is attached.

A wireless communication device according to the present invention performs wireless communication using an antenna, and supports the wireless communication device by sandwiching it between a belt of a user with a belt clip.
An extension inductor connected in series to the antenna and connected to a radio transceiver circuit;
Switch means connected in parallel with the extension inductor;
An infrared light emitting element and an infrared light receiving element, and when the belt clip is not sandwiched, the infrared light from the infrared light emitting element is reflected by the belt clip and received by the infrared light receiving element; Detecting means for detecting the presence or absence of the belt by not receiving the infrared light from the infrared light emitting element to the infrared light receiving element,
Control means for turning on the switch means when it is detected that the belt is present.

  In the wireless communication device, the control means modulates the infrared carrier wave according to a predetermined signal code, and demodulates the modulated infrared light to determine whether to detect the signal code. The presence or absence of infrared detection is performed.

In the wireless communication apparatus, the switch means is a diode.
When the control means detects that the belt is present, the control means turns on the switch means by causing a conduction current to flow through the diode.

Furthermore, in the wireless communication device, the switch means is a transistor,
When the control means detects that the belt is present, the control means turns on the switch means by applying a predetermined conduction voltage to the gate of the transistor.

  Therefore, according to the wireless communication apparatus of the present invention, the circuit configuration is simpler than that of the conventional example, and the contactless structure and the drip-proof or waterproof structure can be provided for the belt. When the wireless communication device is attached, a wireless communication call can be satisfactorily performed.

It is a block diagram which shows the structure of the portable radio | wireless machine which concerns on one Embodiment of this invention. (A) It is a front view which shows the front of the portable radio | wireless machine of FIG. 1, (b) is a side view when the belt 32 is not pinched | interposed into the belt clip 30 of the portable radio | wireless machine of FIG. 1, (c) is a figure. It is a side view when the belt 32 is pinched | interposed into the belt clip 30 of 1 portable radio | wireless machine. It is a block diagram which shows the structure of the portable wireless apparatus which concerns on a modification. It is a graph which shows the frequency characteristic of reflection coefficient S11 (dB) which shows an impedance matching state when a user has a portable radio | wireless machine. It is a graph which shows the frequency characteristic of reflection coefficient S11 (dB) in the state where the portable radio | wireless machine contact | adhered to the user and the impedance matching state shifted | deviated. It is a graph which shows the frequency characteristic of reflection coefficient S11 (dB) which shows the prior art for solving the problem demonstrated using FIG.4 and FIG.5.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In addition, in each following embodiment, the same code | symbol is attached | subjected about the same component.

  FIG. 1 is a block diagram showing a configuration of a portable wireless device according to an embodiment of the present invention. In FIG. 1, a portable wireless device according to this embodiment includes an antenna 1 that is an external antenna such as a whip antenna, an extension inductor 2 that is a built-in antenna, a switch 3, a coupling capacitor 4, and a wireless transmission circuit 11. Infrared light emission for detecting the presence or absence of the belt 32 when supporting the portable wireless device by sandwiching the belt clip 30 of the portable wireless device between the wireless receiver circuit 12, the connection terminals T1 and T2, and the belt 32 of the user. A detection circuit including an infrared LED (Light Emitting Diode) 21 as an element and an infrared reception module 22 including an infrared light receiving element, and an MPU (Micro-Processing Unit) 10 as a control means for controlling these circuits are provided.

  The portable wireless device according to the present embodiment is connected in series to the antenna 1 in a portable wireless device that performs wireless communication using the antenna 1 and supports the portable wireless device by being sandwiched between the belt 32 of the user and the belt 32 of the user. And includes an extension inductor 2 connected to the radio transmission / reception circuits 11 and 12, a switch 3 connected in parallel with the extension inductor 2, an infrared LED 21 and an infrared reception module 22, and a belt 32 is sandwiched between the belt clip 30. When there is not, the infrared ray from the infrared LED 21 is reflected by the belt clip 30 and received by the infrared receiving module 22, while the belt 32 is sandwiched between the belt clip 30 and the infrared ray from the infrared LED 21 is By not receiving light in the infrared receiving module 22, the above A detection circuit for detecting the presence or absence of belt 32, when it detects that there is the belt 32, characterized in that it comprises a MPU10 to turn on the switch 3.

  In FIG. 1, a radio signal received by an antenna 1 is input to a radio reception circuit 12 via an extension inductor 2 or a switch 3 and a coupling capacitor 4. The radio reception circuit 12 performs reception processing such as high frequency amplification, frequency conversion, demodulation, and low frequency amplification on an input radio signal, and transmits a low frequency signal such as a call voice signal to the speaker via the connection terminal T2. 6 (may be an earphone). On the other hand, the call voice input from the microphone 5 is converted into a low-frequency signal and then input to the wireless transmission circuit 11 via the connection terminal T1. The wireless transmission circuit 11 performs transmission processing such as low-frequency amplification, modulation, frequency conversion, and power amplification on the input low-frequency signal, and connects the wireless signal to the coupling capacitor 4 and the extension inductor 2 or the switch 3. Through the antenna 1 and radiate. The MPU 10 controls operations of the wireless transmission circuit 11 and the wireless reception circuit 12.

  The MPU 10 emits infrared light by passing a driving current through the infrared LED 21. In the belt clip 30 when there is no belt, the MPU 10 is reflected inside the belt clip 30 and received by the infrared receiving module 22, and then converted into an electric signal. Is output. Here, the MPU 10 can reduce the influence of external noise such as sunlight by modulating the carrier signal of the driving current for the infrared LED 21 according to a signal code such as a predetermined bit code (unique code or PN code code). it can.

  2 (a) is a front view showing the front of the portable radio shown in FIG. 1, and FIG. 2 (b) is a side view when the belt 32 is not sandwiched between the belt clip 30 of the portable radio shown in FIG. 2 (c) is a side view when the belt 32 is sandwiched between the belt clip 30 of the portable radio shown in FIG.

  In the present embodiment, it is determined whether or not the belt 32 is sandwiched between the belt clips 30 based on whether or not infrared rays are reflected. An infrared carrier wave is generally used. For example, a 38 KHz carrier wave is preferably used. As described above, in order to reduce the influence of external noise such as sunlight, the infrared carrier wave is modulated with a signal code such as a predetermined bit pattern (for example, a unique code or a PN code).

  In FIG. 2A, a display unit 13 such as a liquid crystal display and an operation unit 14 including knobs for channel selection, volume adjustment, function selection, and the like are provided on the front surface of the portable wireless device.

(1) When the belt 32 is not provided (FIG. 2B)
The infrared LED 21 is caused to emit light using the infrared driving current modulated by the signal pattern generated by the MPU 30. Infrared light modulated by the signal pattern emitted from the infrared LED 21 is reflected inside the belt clip 30 and input to the infrared receiving module 22. An electric signal output from the infrared receiving module 22 is input to the MPU 10. The MPU 10 determines whether or not it matches the signal pattern generated by itself. If the signal patterns match, it is determined that the infrared reflected light is returning, and it is determined that the belt 32 is not sandwiched.

(2) With belt 32 (FIG. 2 (c))
The infrared LED 21 is caused to emit light using the infrared driving current modulated by the signal pattern generated by the MPU 10. At this time, the belt 32 sandwiched between the belt clips 30 blocks the infrared LED 21 and the infrared receiving module 22, and the infrared reflected light does not return to the infrared receiving module 22. Since the MPU 10 does not receive a modulated electric signal, it is determined that the belt 32 is sandwiched.

  The antenna matching circuit is switched as described below by the above belt detection means. Hereinafter, impedance matching of the portable wireless device will be described.

  FIG. 4 is a graph showing the frequency characteristic of the reflection coefficient S11 (dB) indicating the impedance matching state when the user holds the portable wireless device. FIG. 5 is a graph showing the frequency characteristic of the reflection coefficient S11 (dB) in a state where the portable wireless device is in close contact with the user and the impedance matching state is shifted. Further, FIG. 6 is a graph showing the frequency characteristic of the reflection coefficient S11 (dB) showing the prior art for solving the problems described with reference to FIGS. These reflection coefficients S11 can be measured, for example, by connecting a network analyzer to the antenna terminal of the portable wireless device.

  First, the technical background of the antenna matching circuit will be described below.

  The portable radio uses an antenna 1 that matches the target frequency to be transmitted and received. In many cases, it is matched on the assumption that the radio main body is used in hand. When a portable wireless device is used for business purposes, it is required to be hands-free, and a speaker microphone or an earphone microphone is used. In that case, the portable wireless device is used with the belt clip 30 hanging around the waist. The portable wireless device comes into close contact with the human body, the dielectric constant of the antenna 1 changes, the resonance frequency shifts to a lower side than the target frequency, and transmission / reception performance deteriorates. This is because the human body tissue has a relatively high dielectric constant.

  In the state where the portable wireless device is held and matched, as shown in FIG. 4, the antenna length is adjusted so that the resonance frequency when held in the hand is best at a predetermined target frequency fc to minimize reflection. Next, in a state where the portable wireless device is in close contact with the human body and the alignment is shifted, as shown in FIG. 5, when the portable wireless device is in close contact with the human body, the dielectric constant of the antenna 1 changes and the resonance frequency shifts to a lower side. That is, the best matching point of the antenna 1 is shifted from the target frequency fc to a lower frequency fL as indicated by the arrow 101. At this time, reflection at the target frequency fc increases, the substantial transmission power decreases, and the received radio signal level also decreases, affecting transmission / reception performance.

  As a compromise in the prior art, when a portable wireless device is commercialized, it is assumed that the portable radio device is supported by the belt clip 30 and is in close contact with the human body. The compromise is found so as to be the center of the change width (102 in FIG. 6) of the resonance frequency with respect to the resonance frequency fH. Assuming that the portable wireless device is in close contact with the human body and the resonance frequency shifts to the lower side, the antenna length is set shorter in advance. For this reason, the transmission / reception performance is inevitably lowered rather than the best matching state.

  On the other hand, in this embodiment, when the belt 32 is attached to the belt clip 30 and the portable wireless device is in close contact with the human body, the antenna length is set to be short in advance in anticipation that the resonance frequency shifts to the lower side. That is, as a measure for improving the above-described performance degradation, the state where the belt 32 is attached to the belt clip 30 is detected, and the impedance matching circuit of the antenna is automatically switched to correct the resonance point. Here, the belt clip 30 attached to the portable wireless device is used to detect that it is sandwiched between the belts 32 as described above, preferably using modulated infrared rays. When infrared rays are not detected, it is determined that the belt 32 is sandwiched and the antenna matching circuit is electrically controlled.

  Here, when the belt 32 is not sandwiched, infrared rays are detected, the switch 3 is left off, and the total antenna length of the antenna 1 and the extension inductor 2 is used.

  On the other hand, when the portable wireless device is attached to the belt 32 and in close contact with the human body, infrared rays are not detected and the switch 3 is turned on. Here, the extension inductor 2 is short-circuited, and the total length of the antenna is shortened. Although the portable radio device is in close contact with the human body and the resonance frequency of the antenna is shifted to a lower one, impedance matching can be achieved in the best state by shortening the antenna length.

  According to the portable wireless device according to the present embodiment configured as described above, when the belt 32 is not sandwiched between the belt clips 30, the infrared rays from the infrared LEDs 21 are reflected by the belt clips 30 and received by the infrared reception module 22. On the other hand, when the belt 32 is sandwiched between the belt clips 30, the infrared receiving module 22 does not receive the infrared rays from the infrared LED 21, thereby detecting the presence of the belt 32 and the presence of the belt 32. Sometimes switch 3 is turned on. As a result, when the portable radio is supported by the belt 32 via the belt clip 30 and the user makes a call using the portable radio, the antenna length is shortened because the portable radio is close to the human body that is the user. Thus, the impedance matching between the antenna 1 and the wireless transmission / reception circuits 11 and 12 can be adjusted to set the best impedance matching state. As a result, the user can make a wireless communication call satisfactorily when the portable wireless device is attached using the belt clip 30 of the portable wireless device.

  FIG. 3 is a block diagram illustrating a configuration of a portable wireless device according to a modification. In FIG. 3, a diode D is provided instead of the switch 3. A DC cut capacitor C2 is connected in series to the extension inductor 2, and the diode D is connected in parallel to the series circuit of the switch 3 and the capacitor C2. Further, R1 and R2 are resistors having a high resistance value with respect to the high frequency, and the capacitor C1 constitutes a blocking filter that blocks the high frequency signal from being input to the MPU 10. Here, when the extension inductor 2 is short-circuited, the MPU 10 supplies a predetermined on-current Ion to the diode D to turn on the diode D. Here, the on-current Ion flows from the MPU 10 to the ground terminal via the resistor R1, the diode D, and the resistor R2. On the other hand, when the on-current Ion does not flow through the diode D, the diode D is turned off. In addition, although the diode D is used in the modification of FIG. 3, the present invention is not limited to this, and instead of the switch 3, a MOS transistor is connected and switching between applying an on-voltage to the gate is performed. It may be switched whether or not the extension inductor 2 is short-circuited.

  In the above embodiment, the portable wireless device has been described. However, the present invention is not limited to this, and can be applied to a wireless communication device such as a wireless device including at least the belt clip 30 and a mobile phone.

  As described in detail above, according to the wireless communication device of the present invention, the circuit configuration is simpler than that of the conventional example, and the contactless structure with respect to the belt and the drip-proof or waterproof structure are provided. Thus, when the wireless communication device is attached using a belt clip, a wireless communication call can be performed satisfactorily.

1 ... External antenna,
2. Extension inductor,
3 ... switch,
4 ... Coupling capacitor,
5 ... Microphone,
6 ... Speaker,
10 ... MPU,
11 ... wireless transmission circuit,
12: Wireless receiver circuit,
21 ... Infrared LED,
22: Infrared receiving module,
30 ... belt clip,
32 ... Belt,
D ... Diode,
R1, R2 ... resistance,
C1, C2 ... capacitors,
T1, T2 ... connection terminals.

Claims (4)

In a wireless communication device that performs wireless communication using an antenna and supports the wireless communication device by sandwiching it between a user's belt with a belt clip,
An extension inductor connected in series to the antenna and connected to a radio transceiver circuit;
Switch means connected in parallel with the extension inductor;
An infrared light emitting element and an infrared light receiving element, and when the belt clip is not sandwiched, the infrared light from the infrared light emitting element is reflected by the belt clip and received by the infrared light receiving element; Detecting means for detecting the presence or absence of the belt by not receiving the infrared light from the infrared light emitting element to the infrared light receiving element,
And a control means for turning on the switch means when it is detected that the belt is present.   The control means modulates the infrared carrier wave according to a predetermined signal code, demodulates the modulated infrared ray, and determines whether to detect the signal code, thereby determining whether or not the modulated infrared ray is detected. The wireless communication device according to claim 1, wherein the wireless communication device is performed. The switch means is a diode;
3. The wireless communication apparatus according to claim 1, wherein the control means turns on the switch means by flowing a conduction current through the diode when detecting that the belt is present. The switch means is a transistor;
3. The wireless communication apparatus according to claim 1, wherein the control means turns on the switch means by applying a predetermined conduction voltage to the gate of the transistor when detecting that the belt is present. .

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