JP2010068169A - Receiver, antenna, and relay cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure sufficient characteristics even when connecting an external antenna through the connector of an earphone or the like. <P>SOLUTION: Terminals (3, 6) other than an antenna input terminal (1) and a ground terminal (10) are provided with a reactance adjustment circuit 30 for adjusting reactance between the antenna input terminal (1) and the ground terminal (10). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a receiving device, an antenna, and a relay cable, and can be applied to, for example, a mobile phone capable of receiving digital television broadcasts. The present invention connects an external antenna via an earphone connector or the like by providing a reactance adjustment circuit for adjusting a reactance between the antenna input terminal and the ground terminal at a terminal different from the antenna input terminal and the ground terminal. Even in such a case, sufficient characteristics can be ensured.

  2. Description of the Related Art Conventionally, mobile phones that can receive television broadcasts or the like receive broadcast waves using a built-in antenna or a built-in rod antenna. Here, the built-in antenna has a configuration in which a wiring pattern or the like of a cellular phone functions as an antenna. The built-in antenna has the advantage that the design of the mobile phone is not impaired. However, the built-in antenna has disadvantages such as inferior sensitivity to the rod antenna and easily affected by internal noise.

  The built-in rod antenna is a rod antenna that is incorporated in a mobile phone so as to be extendable or foldable. The rod antenna has an advantage that sensitivity and the like are superior to those of the built-in antenna. However, the rod antenna has a drawback in that the design of the mobile phone is damaged and the antenna protrudes. In particular, in the case of the built-in type, there is a drawback that the mechanical structure becomes complicated.

Therefore, in recent years, an external antenna such as an earphone antenna or an external rod antenna that is connected to a mobile phone only when a broadcast wave is received using a connector for connecting the earphone is provided. Here, the earphone antenna uses an earphone cable as an antenna as disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-104591. The external antenna can prevent the deterioration of sensitivity and the influence of internal noise without impairing the design of the mobile phone.
Japanese Patent Laid-Open No. 2007-104591

  However, a connector for connecting an earphone of a cellular phone is a connector intended for signal transmission below an audible frequency band. Therefore, when an external antenna is connected and used, there is a problem that high frequency loss increases and sufficient characteristics cannot be secured.

  As a method for solving this problem, a method of connecting an external antenna via a high frequency connector is conceivable. However, this method has problems such as an increase in the number of connectors in the mobile phone, making it difficult to downsize the mobile phone.

  The present invention has been made in consideration of the above points, and intends to propose a receiving device, an antenna, and a relay cable that can ensure sufficient characteristics even when an external antenna is connected via an earphone connector or the like. To do.

  In order to solve the above-mentioned problems, the invention of claim 1 is applied to a receiving device, has a connector for connecting an external device, and receives a desired broadcast wave by a built-in tuner, and via the connector. And an external antenna for connecting a portion functioning as an antenna to the antenna input terminal of the tuner via the antenna input terminal of the connector. The main unit grounds the ground terminal of the connector. The external antenna is provided with a reactance adjustment circuit for adjusting a reactance between the antenna input terminal and the ground terminal between the ground terminal and the terminal different from the antenna input terminal and the ground terminal.

  The invention according to claim 4 is applied to an antenna and is connected to a main unit having a tuner via a connector, and a portion functioning as an antenna is connected to an antenna input end of the tuner via an antenna input terminal of the connector. Connecting. A reactance adjustment circuit for adjusting a reactance between the antenna input terminal and the ground terminal is provided between the ground terminal and the terminal different from the antenna ground terminal and the antenna input terminal.

  Further, the invention of claim 5 is applied to a relay cable, one end is connected to a main unit having a tuner via a connector, an external antenna is connected to the other end, and the antenna input terminal of the connector An external antenna is connected to the antenna input terminal of the tuner. A reactance adjustment circuit for adjusting a reactance between the antenna input terminal and the ground terminal is provided between the ground terminal and the terminal different from the ground terminal of the connector and the antenna input terminal.

  The invention of claim 6 is applied to a relay cable, one end of which is connected to a main unit having a tuner via a connector, transmits a signal and / or power of the main unit, and passes through an antenna input terminal of the connector. Then, the part functioning as an antenna is connected to the antenna input terminal of the tuner. A reactance adjustment circuit for adjusting a reactance between the antenna input terminal and the ground terminal is provided between the ground terminal and the terminal different from the ground terminal of the connector and the antenna input terminal.

  According to the configuration of the first, fourth, fifth, or sixth aspect, the reactance adjustment circuit can variously adjust the reactance of the antenna input terminal due to the parasitic capacitance and the parasitic inductance. Therefore, deterioration of characteristics due to parasitic capacitance and parasitic inductance can be prevented.

  According to the present invention, even when an external antenna is connected via an earphone connector or the like, sufficient characteristics can be ensured.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. The description will be given in the following order.

1. 1. First embodiment 2. Second embodiment 3. Third embodiment 4. Fourth embodiment Modification <First Embodiment>
[Configuration of the embodiment]
FIG. 2 is a perspective view showing a receiving system according to the first embodiment of the present invention. In this receiving system 1, a mobile phone 2 as a main device is a mobile phone having a function of receiving a broadcast wave and a function of reproducing music content recorded on a recording medium, and is provided with a jack 3 for connecting an earphone to the side. . In the receiving system 1, an external rod antenna 4 is connected to the jack 3 of the mobile phone 2.

  Here, as shown in FIG. 3, the external rod antenna 4 has an antenna element portion 5 that is a rod-shaped conductor that functions as an antenna, and a plug 6 is disposed at one end of the antenna element portion 5. The external rod antenna 4 is connected to the mobile phone 2 by connecting the plug 6 to the jack 3 of the mobile phone 2. The external rod antenna 4 is set so that the length of the antenna element unit 5 is approximately ¼ wavelength in the approximate center frequency of the reception frequency band of the mobile phone 2.

  As a result, as shown in FIG. 4 and FIG. 5, the reception system 1 causes the external rod antenna 4 to function as a quarter-wave monopole antenna in the reception frequency band of the tuner 8 provided in the mobile phone 2. A desired broadcast wave is received by a tuner 8 built in the telephone 2.

  Here, FIG. 6 is a perspective view showing a part of the jack 3 of the mobile phone 2 in detail. The jack 3 is a 10-pin small and flat multi-pole connector, and terminals 9A to 9J are continuously arranged in the longitudinal direction, and these terminals 9A to 9J are closely arranged. In the jack 3, the terminals 9A to 9J protrude and bend to the back side, and the ends of the bent terminals 9A to 9J are soldered to the corresponding wiring patterns 11A, 11B, 11C,. 10 is implemented. Here, the wiring board 10 is provided with a high-frequency cutoff circuit by chip inductors 12A, 12B, 12C,. Here, the high-frequency cutoff circuit prevents the high-frequency signal induced by the earphone cable or the like from entering the mobile phone 2 and radiating the internal noise of the mobile phone 2 to the outside.

  FIG. 7 is an exploded perspective view showing in detail the portion of the plug 6 of the external rod antenna 4. The plug 6 has a portion 6A to be inserted into the jack 3 having a rectangular cross section, and terminals corresponding to the terminals 9A to 9J of the jack 3 are arranged inside the portion 6A. The plug 6 is formed such that the back side of the part 6A is wide, and the back side of each terminal protrudes from the wide part. The plug 6 is connected to the wiring pattern of the wiring board 15 by inserting a portion protruding from the back side of each terminal into a through hole of the wiring board 15 and soldering. In addition, a predetermined wiring pattern of the wiring board 15 is connected to the antenna element portion 5 through the conductive wire L. The plug 6 is provided on the wiring board 15 as necessary with a high-frequency cutoff circuit using chip inductors 16A and 16B. The plug 6 is molded with resin together with the conductor L and the antenna element portion 5 on the back side where the wiring board 15 is arranged.

  FIG. 8 is a diagram illustrating an example in which the earphone 20 is connected to each terminal of the jack 3 and the plug 6. In the following, each terminal of the jack 3 and the plug 6 is indicated by numerals 1 to 10. In the mobile phone 2, the fourth and fifth terminals 4 and 5 of the jack 3 and the plug 6 are assigned to the hot side of the right channel audio signal SAR and the left channel audio signal SAL, and the tenth terminal 10 is assigned to the ground. It is done. Thus, the cellular phone 2 internally grounds the tenth terminal 10 of the jack 3, and the right channel audio signal SAR and the left channel audio signal SAL are connected to the fourth and fifth terminals of the jack 3 via the amplifier circuits 21R and 21L. Are output to terminals 4 and 5. High-frequency cutoff circuits 23R and 23L using chip inductors are disposed between the amplifier circuit 21R and the fourth terminal 4 and between the amplifier circuit 21L and the fifth terminal 5, respectively.

  In the earphone 20, the fourth and fifth terminals 4 and 5 of the plug 6 are connected to the hot side of the right and left channel speakers 22R and 22L, and the cold side of these speakers 22R and 22L is the tenth of the plug 6. Connected to terminal 10.

  The third and sixth terminals 3 and 6 of the jack 3 and the plug 6 are assigned for detecting the connection of an external device to the jack 3. In the mobile phone 2, the third terminal 3 of the jack 3 is input to the detection circuit 26 via the high-frequency cutoff circuit 24, and the sixth terminal 6 of the jack 3 is connected to the detection circuit 27 via the high-frequency cutoff circuit 25. Entered. The cellular phone 2 detects the connection of an external device such as the earphone 20 by detecting the DC potential of the corresponding terminals 3 and 6 by the detection circuits 26 and 27. Further, in response to a user operation, processing such as switching of the output of the audio signals SAL and SAR is executed between the built-in speaker and the jack 3. The first terminal 1 is assigned to the antenna input terminal and is connected to the antenna input terminal of the tuner 8 via the capacitor 28.

  In the earphone 20, the third and sixth terminals 3 and 6 of the plug 6 are connected to the tenth terminal on the wiring board 10 (FIG. 6). In addition, the first terminal 1 of the plug 6 is connected to only the wiring pattern on the wiring substrate 10 together with the remaining terminals 2 and 7 to 9 and is set to an empty terminal that is not connected to any part.

  FIG. 1 is a connection diagram showing the connection of the external rod antenna 4 in comparison with FIG. In the external rod antenna 4, the antenna element unit 5 is connected to the antenna input terminal 1 of the plug 6, and the third and sixth terminals 3 and 6 are connected to the tenth terminal 10 via the reactance adjustment circuit 30. . The remaining terminals 2 and 7 to 9 are set as empty terminals. Here, the reactance adjustment circuit 30 is a circuit that adjusts the impedance between the antenna input terminal 1 and the ground terminal 10. In the receiving system 1, as shown in FIG. 9 in comparison with FIG. 1, an inductor 31 made of ferrite beads is applied to the reactance adjustment circuit 30, and the third and sixth terminals 3 and 6, the tenth terminal 10, Is short-circuited in a direct current manner. Further, in the receiving frequency band of the tuner 8, the third and sixth terminals 3 and 6 and the tenth terminal 10 are short-circuited by the impedance of the inductor 31. The inductor 31 is selected to have an impedance of about 1 [kΩ] in the UHF band.

[Operation of the embodiment]
In the above configuration, in the reception system 1, when enjoying music content with the earphone 20, the plug 6 of the earphone 20 is connected to the jack 3 (FIGS. 2 and 8), so that the connection detection terminal 3, 6 is detected by the mobile phone 2, and connection of an external device is detected by the mobile phone 2. Further, when the user instructs the output of the audio signals SAL and SAR to the earphone 20 by detecting this connection, the audio signals SAL and SAR are output to the terminals 4 and 5 of the jack 3. Thereby, in the reception system 1, the audio signal is reproduced from the speakers 22L and 22R of the earphone 20 and provided to the user.

  On the other hand, when a broadcast wave is received by an external antenna, the external rod antenna 4 is connected to the jack 3 to which the earphone 20 is connected instead of the earphone 20 (FIGS. 2 to 5). As a result, in the receiving system 1, the high frequency signal induced in the antenna element portion 5 of the external rod antenna 4 is provided in the mobile phone 2 via the antenna input terminal 1 of the plug 6 and the antenna input terminal 1 of the jack 3 in this order. The signal is input to the antenna input terminal of the tuner 8. As a result, the receiving system 1 can receive broadcast waves with sufficient reception sensitivity without being affected by internal noise, and can prevent the design of the mobile phone 2 from being deteriorated.

  However, since the jack 3 and the plug 6 are originally small and flat connectors for the purpose of transmitting audio signals (FIGS. 6 and 7), the frequency band of broadcast waves that is much higher than the audible frequency. Therefore, it is not possible to secure sufficient characteristics for transmission of broadcast waves. As a result, it is difficult to secure sufficient characteristics if the external rod antenna 4 is connected without taking any measures.

  That is, as shown in FIG. 10 in comparison with FIG. 1, there are parasitic capacitances C1, C2, C3, etc. between the terminals of the jack 3 and the plug 6, and the parasitic inductances L1, L2, L3, etc. exist. These parasitic capacitances C1, C2, C3 and parasitic inductances L1, L2, L3 have a configuration in which a plurality of terminals are arranged in close contact with each other so that the jack 3 and the plug 6 are configured for signal transmission below the audible frequency band. Therefore, it cannot be ignored in the frequency band of broadcast waves. As a result, in the receiving system 1, a decrease in gain, variation in characteristic impedance, etc. cannot be ignored in the frequency band of the broadcast wave, and the antenna characteristics deteriorate.

  When creating wiring patterns that are wide and short in consideration of high-frequency characteristics, the parasitic capacitance and parasitic inductance are reduced. Conversely, when wiring patterns are created narrow and long for high-density mounting. , Parasitic capacitance and parasitic inductance increase. Accordingly, the antenna characteristics deteriorate as the wiring pattern is densely formed and the component mounting density in the mobile phone increases.

  Specifically, FIG. 11 is a diagram illustrating the antenna gain when the terminals 3, 6, and 10 are directly short-circuited without providing the impedance adjustment circuit 30. 12 and 13 are charts showing the characteristics of FIG. 11 in detail. 11 to 13, as shown in FIG. 14 in comparison with FIG. 1, the terminals 3 and 6 of the jack 3 are opened on the mobile phone 2 side, and the rod antenna 45 having a length of 120 [mm] This is an example in which the mobile phone 2 is connected to an evaluation board having a ground size of 85 × 45 [mm].

  According to FIGS. 11 to 13, as indicated by an arrow A, it can be seen that the antenna gain is lowered on the high frequency side of the UHF band. FIGS. 15 and 16 are diagrams showing the standing wave ratio in comparison with FIGS. 11 to 13. In FIG. 15, the broadcast wave band in the UHF band is indicated by a broken line. FIG. 16 shows the characteristics of S11. According to FIG. 15, it can be seen that resonance frequencies are generated at two locations in the UHF band. From the antenna length, the resonance frequency on the 500 [MHz] side of these two resonance frequencies is due to the antenna element unit 5, and the resonance frequency on the frequency 800 [MHz] side is due to parasitic capacitance and parasitic inductance. It is.

  On the other hand, FIGS. 17 to 19 show a case in which the terminals 3 and 6 of the jack 3 are short-circuited on the mobile phone 2 side and are connected to the terminal 10 with a capacitance of 2 [pF] in comparison with FIGS. It is a figure which shows the characteristic. In this case, it can be seen that the frequency band in which the antenna gain indicated by the arrow A decreases is reduced by the amount of increase in the capacity. 20 and 21 are diagrams showing the standing wave ratios in the examples of FIGS. 17 to 19 in comparison with FIGS. 15 and 16.

  22 to 24, in contrast to FIGS. 11 to 13, when the terminals 3 and 6 of the jack 3 are short-circuited on the mobile phone 2 side and connected to the terminal 10 with a capacity of 4 [pF]. It is a figure which shows the characteristic. In this case, it can be seen that the frequency band in which the antenna gain indicated by the arrow A decreases is further reduced by the increase in capacity. 25 and 26 are diagrams showing the standing wave ratios in the examples of FIGS. 22 to 24 in comparison with FIGS. 15 and 16.

  As a result, it can be seen that the antenna gain varies due to the parasitic capacitance and parasitic inductance of the jack 3 and plug 6. That is, in this case, an impedance circuit for deteriorating antenna characteristics is provided at the antenna input terminal of the plug 6 when viewed from the external rod antenna 4 side due to the parasitic capacitance and parasitic inductance of the jack 3 and the plug 6. In the reception system 1, the antenna characteristics are deteriorated by the impedance circuit.

  Therefore, in this embodiment, in the plug 6, a reactance adjustment circuit is provided between the ground terminal 10 and a desired terminal, and this reactance adjustment circuit prevents deterioration of the antenna characteristics due to parasitic capacitance and parasitic inductance. More specifically, an inductor is applied to the reactance adjustment circuit. Further, since the inductor has a direct current resistance of approximately 0, a reactance adjustment circuit is arranged between the terminals 3 and 6 that are grounded to the ground and the ground terminal 10 in the plug 6.

  27 to 31 show a case where the terminals 3 and 6 of the jack 3 are opened on the mobile phone 2 side and this reactance adjustment circuit 30 is provided by comparison with FIGS. 11 to 13, 15 and 16. FIG. The reactance adjustment circuit 30 is an inductor made of ferrite beads. According to FIGS. 27 to 29, by providing the reactance adjustment circuit 30 in comparison with FIGS. 11 to 13, the decrease in the antenna gain on the high frequency side of the UHF band is improved, and the fluctuation of the antenna gain in the UHF band. It can be seen that is decreasing. Further, according to FIGS. 30 and 31, it can be seen that the frequency characteristic of the standing wave ratio is a single peak characteristic, and there is no resonance point due to parasitic capacitance and parasitic inductance in the UHF band.

  On the other hand, FIGS. 32 to 36 and FIGS. 37 to 41 short-circuit the terminals 3 and 6 of the jack 3 on the mobile phone 2 side by comparing with FIGS. 17 to 21 and FIGS. 22 to 26, respectively. It is a figure which shows the case where the reactance adjustment circuit 30 is provided when connecting with the terminal 10 by the capacity | capacitance of 2 [pF] and 4 [pF]. According to FIGS. 32 to 34 and FIGS. 37 to 39, in comparison with FIGS. 17 to 19 and FIGS. 22 to 24, respectively, in this case as well, by providing the reactance adjustment circuit 30, local in the UHF band can be obtained. It can be seen that the reduction of the antenna gain is improved and the fluctuation of the antenna gain in the UHF band can be reduced.

  Accordingly, in this embodiment, sufficient characteristics can be ensured even when an external antenna is connected via the connector of the earphone.

[Effect of the embodiment]
According to the above configuration, by providing the reactance adjustment circuit that adjusts the reactance between the antenna input terminal and the ground terminal between the terminal different from the antenna input terminal and the ground terminal and the ground terminal, the connector of the earphone Even when an external antenna is connected through the like, sufficient characteristics can be secured.

  In addition, by using the terminal for disposing the reactance adjustment circuit as an external device detection terminal, it is possible to effectively use the external device detection terminal to ensure sufficient characteristics.

<Second Embodiment>
FIG. 42 is a perspective view showing a receiving system according to the second embodiment of the present invention. In this receiving system 41, a relay cable 42 is connected to the mobile phone 2, and the mobile phone 2 is connected to the external antenna 43 via the relay cable 42. In this receiving system 41, the same components as those in the receiving system 1 are indicated by the corresponding reference numerals, and redundant description is omitted.

  Here, as shown in FIG. 43, the relay cable 42 has the plug 6 disposed at one end of the coaxial cable 44, and the core wire of the coaxial cable 44 and the antenna input terminal 1 and the ground terminal 10 (see FIG. 1) of the plug 6. Each of the covered wires is connected. A high frequency coaxial connector 45 is provided at the other end of the coaxial cable 44, and a coaxial cable 47 extending from the external antenna 43 is connected to the high frequency coaxial connector 45.

  In the relay cable 42, the connection detection terminals 3 and 6 of the plug 6 are short-circuited in the same manner as the external rod antenna 4 of the first embodiment, and an inductor is used between the terminals 3 and 6 and the ground terminal 10. A reactance adjustment circuit 30 is provided. As a result, the relay cable 42 reduces transmission loss of broadcast waves received by the external antenna 43.

  FIG. 44 is a characteristic curve diagram showing transmission loss when terminals 3 and 6 of jack 3 are set to open on the mobile phone 2 side. Symbol L1 is a characteristic when the reactance adjustment circuit 30 using an inductor is not arranged, and symbol L2 is a characteristic when the reactance adjustment circuit 30 using an inductor is arranged.

  45 to 48, in comparison with FIG. 44, the terminals 3 and 6 of the jack 3 are short-circuited on the mobile phone 2 side, and the capacitors 2 [pF], 4 [pF], 10 [pF], 1000 It is a characteristic curve figure at the time of connecting to a ground terminal by the capacity | capacitance of [pF]. 44 to 48, it is understood that when the reactance adjustment circuit 30 is not disposed, the transmission loss is locally degraded, and the locally degraded frequency is gradually lowered due to an increase in parasitic capacitance. It can also be seen that the local degradation of the transmission loss can be prevented by the arrangement of the reactance adjustment circuit 30.

  According to this embodiment, it is possible to prevent deterioration of transmission loss in a relay cable that relays an external antenna.

<Third Embodiment>
FIG. 49 is a perspective view showing a receiving system according to the third embodiment of the present invention. The receiving system 51 connects an earphone 53 to the mobile phone 2 via a relay cable 52 and receives a broadcast wave by an earphone antenna configured by the relay cable 52.

  Here, in the earphone 53, cables extending from the right channel speaker 54R and the left channel speaker 54L are combined into one cable, and a three-pin plug 55 is connected to one end of the cable.

  As shown in detail in FIG. 50, the relay cable 52 has a plug 6 disposed at one end of the multi-core coaxial cable 56 and a jack 57 for connecting the plug 55 of the earphone 53 to the other end. Here, the multicore coaxial cable 56 is a cable in which a plurality of core wire cables LL, LR, and LG are covered with a covered wire SS as shown in FIG. In this embodiment, the number of core cables is set to three, and audio signals are transmitted using the three core cables LL, LR, and LG. Therefore, in the relay cable 52, the three core wire cables LL, LR, and LG on the side of the mobile phone 2 are connected to the fifth, fourth, and fourth plugs 6 via the high-frequency cutoff circuits 61, 62, and 63 using chip inductors, respectively. 3 terminals 5, 4 and 3. The ends of the core wire cables LL, LR, LG on the earphone 53 side are connected to corresponding terminals 57L, 57R, 57G of the jack 57, respectively.

  In the relay cable 52, the end of the covered wire SS on the earphone 53 side is an open end that is not connected to any part, and the end of the covered wire SS on the mobile phone 2 is connected to the antenna input terminal 1 of the plug 6. Thereby, the receiving system 51 receives a desired broadcast wave by the high frequency signal induced on the covered wire SS of the relay cable 52.

  In the relay cable 52, the third and sixth terminals 3 and 6 of the plug 6 are short-circuited, and these terminals 3 and 6 are connected to the ground terminal 10 via the reactance adjustment circuit 30. Accordingly, in this embodiment, the reactance adjustment circuit 30 prevents the gain deterioration of the earphone antenna due to the covered wire SS.

  52 to 54 are diagrams showing the characteristics of the antenna according to this embodiment. 52 to 54, it can be seen that a local decrease in antenna gain is prevented. 55 to 57 are diagrams showing characteristics when only the relay cable is connected for comparison with FIGS. 52 to 54.

  According to this embodiment, an effect similar to that of the first embodiment can be obtained in the earphone antenna.

<Fourth embodiment>
FIG. 58 is a perspective view showing a reception system according to the fourth embodiment of the present invention in comparison with FIG. This receiving system 71 connects an earphone 53 to a mobile phone 73 via a relay cable 72 and receives a broadcast wave by an earphone antenna constituted by the relay cable 72.

  Here, in the mobile phone 73, the antenna input terminal 1 of the jack 3 is grounded by a high-frequency cutoff circuit 74 using a chip inductor, and is connected to the antenna input terminal of the tuner 76 via a capacitor 75. The tuner 76 is a tuner capable of receiving digital television broadcasts and FM broadcasts. The cellular phone 73 is configured in the same manner as the cellular phone 2 of the first embodiment except that the configurations regarding the antenna input terminal 1 and the tuner 76 are different.

  In the relay cable 72, the plug 6 side end of the core wire cable LG assigned to the ground is connected to the covered wire SS and connected to the antenna input terminal 1. The relay cable 72 is configured the same as the relay cable 52 of the third embodiment except that the configuration of the end of the core cable LG at the plug 6 side is different.

  Thus, in this reception system 71, when receiving digital television broadcasting, the covered wire SS functions as a monopole antenna, and a high frequency signal induced in the covered wire SS is input to the tuner 76. On the other hand, when receiving FM broadcasting, the cable of the earphone 53 and the relay cable 72 function as a monopole antenna, and a high frequency signal induced in the cable of the earphone 53 and the relay cable 72 is input to the tuner 76. Is done. Thus, the relay cable 72 forms a two-frequency antenna together with the earphone.

In this embodiment, even when the broadcast wave of two frequency bands is received by the earphone antenna, the same effect as that of the third embodiment can be obtained.
<Modification>
In the above-described embodiment, the case where the reactance adjustment circuit is configured by an inductor has been described. However, the present invention is not limited thereto, and may be configured by a capacitor, a resistor, or the like, and the inductor, the capacitor, and the resistor are combined. You may comprise by a circuit. In the case where the reactance adjustment circuit is constituted by a resistor, the inductance component of the resistor functions to improve the antenna characteristics.

  In the third and fourth embodiments, the case where the earphone is detachably connected to the relay cable via the plug and jack has been described. However, the present invention is not limited to this, and the plug and jack are omitted. Thus, the present invention can be widely applied to the case where the earphone is connected to the relay cable by so-called built-in.

  In the third and fourth embodiments described above, the case where the relay cable is configured by the multi-core coaxial cable has been described. However, the present invention is not limited to this, and the case where the relay cable is configured by a parallel line or the like. Can also be widely applied.

  In the third and fourth embodiments described above, the case where the audio signal is transmitted by the relay cable has been described. However, the present invention is not limited to this, and the analog signal other than the audio signal, various digital signals, and power are transmitted. The present invention can be widely applied to transmission.

  In the above-described embodiment, the case where the present invention is applied to a mobile phone has been described. However, the present invention is not limited thereto, and the reception function such as when the present invention is applied to a portable music player having a reception function. It can be widely applied to various portable devices having

  The present invention can be applied to a mobile phone capable of receiving, for example, digital television broadcasting.

It is a connection diagram which shows the connection of the external rod antenna which concerns on the 1st Embodiment of this invention. 1 is a perspective view showing a receiving system according to a first embodiment of the present invention. It is a top view which shows the external rod antenna of FIG. It is a block diagram with which it uses for description of the receiving system of FIG. FIG. 3 is a connection diagram for explaining the receiving system of FIG. 2. It is a perspective view which shows the site | part of the jack of the mobile telephone of FIG. 2 in detail. FIG. 3 is an exploded perspective view showing details of a plug portion of the external rod antenna of FIG. 2. FIG. 3 is a connection diagram illustrating an example in which earphones are connected to the jack and plug terminals in the reception system of FIG. 2. It is a connection diagram which shows a reactance adjustment circuit in detail. It is a connection diagram for explanation of parasitic capacitance and parasitic inductance. It is a characteristic curve figure which shows the antenna gain at the time of short-circuiting terminal 3, 6, 10 directly, without providing a reactance adjustment circuit. 12 is a chart showing the characteristics of vertical polarization in the characteristic curve diagram of FIG. 11. 12 is a chart showing horizontal polarization characteristics in the characteristic curve diagram of FIG. 11. It is a connection diagram with which it uses for description of the measurement conditions of the characteristic of FIGS. It is a characteristic curve figure which shows the standing wave ratio by the measurement conditions of the characteristic curve figure of FIG. It is a Smith chart which shows the characteristic of FIG. It is a characteristic curve figure which shows the characteristic at the time of connecting between terminals by the capacity | capacitance of 2 [pF]. FIG. 18 is a chart showing vertical polarization characteristics in the characteristic curve diagram of FIG. 17. FIG. It is a graph which shows the characteristic of the horizontal polarization in the characteristic curve figure of FIG. It is a characteristic curve figure which shows the standing wave ratio by the measurement conditions of the characteristic curve figure of FIG. It is a Smith chart which shows the characteristic of FIG. It is a characteristic curve figure which shows the characteristic at the time of connecting between terminals by the capacity | capacitance of 4 [pF]. It is a graph which shows the characteristic of the vertical polarization in the characteristic curve figure of FIG. It is a chart which shows the characteristic of horizontal polarization in the characteristic curve figure of FIG. It is a characteristic curve figure which shows the standing wave ratio by the measurement conditions of the characteristic curve figure of FIG. It is a Smith chart which shows the characteristic of FIG. FIG. 12 is a characteristic curve diagram illustrating a case where a reactance adjustment circuit is provided in comparison with FIG. 11. 28 is a chart showing the characteristics of vertical polarization in the characteristic curve diagram of FIG. It is a chart which shows the characteristic of the horizontal polarization in the characteristic curve figure of FIG. It is a characteristic curve figure which shows the standing wave ratio by the measurement conditions of the characteristic curve figure of FIG. It is a Smith chart which shows the characteristic of FIG. FIG. 18 is a characteristic curve diagram illustrating a case where a reactance adjustment circuit is provided in comparison with FIG. 17. FIG. 33 is a chart showing vertical polarization characteristics in the characteristic curve diagram of FIG. 32. It is a graph which shows the characteristic of the horizontal polarization in the characteristic curve figure of FIG. It is a characteristic curve figure which shows the standing wave ratio by the measurement conditions of the characteristic curve figure of FIG. It is a Smith chart which shows the characteristic of FIG. It is a characteristic curve figure which shows the case where a reactance adjustment circuit is provided by contrast with FIG. It is a graph which shows the characteristic of the vertical polarization in the characteristic curve figure of FIG. FIG. 38 is a chart showing horizontal polarization characteristics in the characteristic curve diagram of FIG. 37. It is a characteristic curve figure which shows the standing wave ratio by the measurement conditions of the characteristic curve figure of FIG. It is a Smith chart which shows the characteristic of FIG. It is a perspective view which shows the receiving system which concerns on the 2nd Embodiment of this invention. FIG. 43 is a plan view showing a relay cable in the reception system of FIG. 42. It is a characteristic curve figure which shows the transmission loss when the terminals 3 and 6 of the jack 3 are opened on the mobile phone side. FIG. 6 is a characteristic curve diagram showing transmission loss when terminals 3 and 6 of the jack 3 are grounded with a capacitance of 2 [pF] on the mobile phone side. FIG. 6 is a characteristic curve diagram showing transmission loss when the terminals 3 and 6 of the jack 3 are grounded with a capacitance of 4 [pF] on the mobile phone side. It is a characteristic curve figure which shows the transmission loss when the terminals 3 and 6 of the jack 3 are grounded with a capacitance of 10 [pF] on the mobile phone side. It is a characteristic curve figure which shows the transmission loss when the terminals 3 and 6 of the jack 3 are grounded with a capacity of 1000 [pF] on the mobile phone side. It is a perspective view which shows the receiving system which concerns on the 3rd Embodiment of this invention. FIG. 50 is a plan view showing a relay cable in the reception system of FIG. 49. It is a connection diagram of the receiving system of FIG. FIG. 50 is a characteristic curve diagram showing antenna gain in the reception system of FIG. 49. 53 is a chart showing vertical polarization characteristics in the characteristic curve diagram of FIG. 52. 53 is a chart showing horizontal polarization characteristics in the characteristic curve diagram of FIG. 52. It is a characteristic curve figure which shows the antenna gain at the time of connecting only a relay cable. It is a graph which shows the characteristic of the vertical polarization in the characteristic curve figure of FIG. It is a graph which shows the characteristic of the horizontal polarization in the characteristic curve figure of FIG. It is a connection diagram which shows the receiving system which concerns on the 4th Embodiment of this invention.

Explanation of symbols

1, 41, 51, 71 ... receiving system, 2 ... mobile phone, 3 ... jack, 4 ... external rod antenna, 5 ... antenna element, 6 ... plug, 8, 76 ... tuner, 20 53 …… Earphone, 30 …… Impedance adjustment circuit, 42, 52, 72 …… Relay cable, 43 …… External antenna, 56 …… Multi-core coaxial cable

Claims (6)

A main unit having a connector for connecting an external device and receiving a desired broadcast wave by a built-in tuner;
An external antenna that is connected to the main body device via the connector, and that connects a portion that functions as an antenna to the antenna input end of the tuner via the antenna input terminal of the connector;
The main unit is
Ground the ground terminal of the connector,
The external antenna is
A receiving device provided with a reactance adjustment circuit for adjusting a reactance between the antenna input terminal and the ground terminal between the ground terminal and the terminal different from the antenna input terminal and the ground terminal. The main unit is
Determine the potential of the external device detection terminal of the connector, detect the connection of the external device to the connector,
The receiving device according to claim 1, wherein a terminal on which the reactance adjustment circuit is disposed is the external device detection terminal. The main unit is
Transmit signals and / or power through the connector's transmission terminals,
The external antenna is
The receiving device according to claim 1, further comprising a cable connected to the transmission terminal and transmitting the signal and / or power. Connected to the main unit having a tuner via a connector, and connected to the antenna input end of the tuner via the antenna input terminal of the connector, a part that functions as an antenna,
A reactance adjustment circuit for adjusting a reactance between the antenna input terminal and the ground terminal is provided between the ground terminal and the terminal different from the ground terminal of the connector and the antenna input terminal. One end is connected to the main unit having a tuner via the connector, an external antenna is connected to the other end, the external antenna is connected to the antenna input end of the tuner via the antenna input terminal of the connector,
A relay cable provided with a reactance adjustment circuit for adjusting a reactance between the antenna input terminal and the ground terminal between the ground terminal and the terminal different from the ground terminal of the connector and the antenna input terminal. One end is connected to the main unit having a tuner via a connector, and transmits a signal and / or power of the main unit,
Via the antenna input terminal of the connector, connect a portion that functions as an antenna to the antenna input end of the tuner,
A relay cable provided with a reactance adjustment circuit for adjusting a reactance between the antenna input terminal and the ground terminal between the ground terminal and the terminal different from the ground terminal of the connector and the antenna input terminal.

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