JP5092942B2 - Receiver, antenna and relay cable - Google Patents

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 a television broadcast. In the present invention, when an audio signal or the like is transmitted by a core wire of a multi-core coaxial cable and an antenna is formed by a covered wire, the impedance between the core wire and the covered wire is adjusted, and the NULL point of the antenna gain is set to a wireless frequency in the vicinity frequency band. By setting the band such as the communication wave, it is possible to sufficiently suppress the wireless communication wave or the like in this nearby frequency band.

  Conventionally, mobile phones that can receive television broadcasts or the like receive broadcast waves with a built-in antenna or an external antenna. Here, the built-in antenna has an advantage that the design of the mobile phone is not impaired. However, the built-in antenna has disadvantages such as inferior sensitivity to an external antenna and being easily affected by internal noise.

In contrast, external antennas include a rod antenna, an earphone antenna, and the like. Here, the rod antenna is characterized by superior sensitivity and the like as compared with 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. On the other hand, the earphone antenna uses an earphone cable as an antenna as disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-104591. The earphone antenna can prevent the deterioration of sensitivity and the influence of internal noise without impairing the design of the mobile phone.
JP 2007-105941 A

  By the way, in a mobile phone, various types of data may be transmitted and received in a frequency band close to the broadcast wave while receiving the broadcast wave. In a conventional mobile phone, there is a problem that a radio communication wave related to data transmission / reception is received by an antenna for receiving a broadcast wave and is input to a tuner without being sufficiently attenuated.

  That is, FIG. 12 is a characteristic curve diagram showing frequency allocation in the UHF band. As the UHF band, a frequency band of 470 to 770 [MHz] is allocated to television broadcasting. Further, a frequency band of 810 [MHz] or more close to the frequency band for television broadcasting is assigned to the mobile phone. In FIG. 12, MCA is a frequency band assigned to the Multi Channel Access System.

  As a result, in this case, the mobile phone cannot normally receive the broadcast wave of the television broadcast due to the interference by the radio communication wave of the mobile phone. In the case of GSM (Global System for Mobile Communications), the tuner input may be excessive due to a large transmission power, and the tuner may be damaged.

  For this reason, a conventional mobile phone is configured so that a multi-stage filter is arranged at the input stage of the tuner and radio communication waves received by a broadcasting antenna are sufficiently suppressed. The multi-stage filter is, for example, a bandpass filter using a surface acoustic wave filter and a filter using an LC circuit configuration.

  However, this method has a problem that the configuration of the mobile phone becomes complicated. There is also a problem that the reception sensitivity of the broadcast wave is lowered due to the loss due to the multistage filter.

  Such a relationship between the radio communication wave and the broadcast wave also occurs when the two tuners receive the broadcast wave. Specifically, when a television method is received by an analog broadcast tuner and a digital broadcast tuner, a broadcast wave in one band affects reception of a broadcast wave in the other band. .

  The present invention has been made in view of the above points, and an object of the present invention is to propose a receiving apparatus, an antenna, and a relay cable that can sufficiently suppress a radio communication wave, a broadcast wave, and the like in a nearby frequency band.

In order to solve the above-mentioned problem, the invention of claim 1 is applied to a receiving device, transmits a desired signal to and from an external device, and receives a broadcast wave by a built-in tuner, Connected to the main unit, the other end is connected to the external device, transmits the signal through a core wire, the external device side end of the covered wire surrounding the core wire is an open end, and the main device side of the covered wire is A relay cable connected to the antenna input end of the tuner;
In order to suppress the adjacent frequency band adjacent to the tuner reception frequency band that affects the reception characteristics of the broadcast wave by the tuner, by setting the impedance between the core wire and the covered wire of the relay cable, The NULL point of the antenna gain due to the covered wire is set to a frequency band in the vicinity of the reception frequency band of the tuner.

The invention according to claim 8 is applied to an antenna, one end is connected to the main unit, the other end is connected to an external device, a signal between the main unit and the external device is transmitted by a core wire, and the core wire is surrounded. The external device side end of the covered wire is an open end, and the main device side of the covered wire is connected to an antenna input end of a tuner provided in the main device,
In order to suppress a nearby frequency band that is close to the reception frequency band of the tuner, which affects the deterioration of the reception characteristics of the broadcast wave by the tuner, by setting the impedance between the core wire and the covered wire, The null point of the gain of the antenna is set to a frequency band close to the reception frequency band of the tuner.

The invention of claim 9 is applied to a relay cable, one end of which is connected to the main unit via a connector, the other end is connected to the earphone via a connector, and an audio signal output from the main unit via a core wire. The external device side end of the covered wire surrounding the core wire is an open end, and the main device side of the covered wire is connected to an antenna input end of a tuner provided in the main device,
In order to suppress a nearby frequency band that is close to the reception frequency band of the tuner, which affects the deterioration of the reception characteristics of the broadcast wave by the tuner, by setting the impedance between the core wire and the covered wire, The null point of the gain of the antenna is set to a frequency band close to the reception frequency band of the tuner.

According to the configuration of claim 1, claim 8, or claim 9, if one end of the covered wire is an open end and the other end of the covered wire is connected to the antenna input end of the tuner, the covered wire functions as an antenna. Broadcast waves can be received. However, in this case, due to capacitive coupling between the coated wire and the core wire, a high-frequency signal induced in the coated wire leaks into the core wire, and as a result, the core wire side functions as an antenna stub. As a result, the antenna characteristics may deteriorate at a specific frequency determined by the electrical length of the stub. Therefore, in order to suppress a nearby frequency band that is close to the reception frequency band of the tuner, which affects the deterioration of the reception characteristics of the broadcast wave by the tuner, an antenna by the covered wire is set by setting an impedance between the core wire and the covered wire. If the null point of the gain is set to a frequency band in the vicinity of the reception frequency band of the tuner, radio communication waves in the vicinity frequency band can be sufficiently suppressed.

  According to the present invention, it is possible to sufficiently suppress a radio communication wave or the like in the near frequency band.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

(1) Configuration of Embodiment FIG. 2 is a perspective view showing a mobile phone system according to Embodiment 1 of the present invention. The mobile phone system 1 receives a television broadcast by an earphone antenna using a relay cable 2 and an earphone 3. For this reason, in the mobile phone system 1, the earphone 3 is connected to the mobile phone 4, which is the main device, via the relay cable 2.

  Here, in the earphone 3, the plug 7 is connected to one end of the cable 6, and the right channel and left channel speakers 8 </ b> R and 8 </ b> L are connected to the other end of the cable 6. In the relay cable 2, a jack 11 for connecting the plug 7 of the earphone 3 is provided at one end of the cable 10, and a plug 12 is provided at the other end of the cable 10. The mobile phone 4 is provided with a jack 13 for connecting the plug 12 on the side surface.

  Here, as shown in FIG. 1, the earphone 3 has a parallel two-wire cable extending from the right channel and left channel speakers 8R and 8L, respectively, so that the right and left channel audio signals share a common ground. Connected to a three-wire flat cable. In the earphone 3, the other end of the three-wire flat cable is connected to the terminals 7L, 7R, and 7G of the 3-pin plug 7. The earphone 3 is formed such that the cable on the left channel side is longer than the cable on the right channel side.

  The cable 10 of the relay cable 2 is a multi-core coaxial cable, and is formed by surrounding three core wire cables LL, LR, LG with a covered wire SS made of a network wire. In the relay cable 2, the three core cables LL, LR, LG are connected to the corresponding terminals 11L, 11R, 11G of the jack 11, respectively, and the core cables LL, LR, LG are respectively hot on the left channel audio signal. The hot side of the right channel audio signal is assigned to the common ground for the left channel audio signal and the right channel audio signal. The covered wire SS is not connected to the earphone 3, and the jack 11 side end is an open end.

  The cable 10 is connected to the plug 12 via the wiring board 14 disposed on the back surface of the plug 12, and the core cables LL, LR, LG and the covered wire SS are individually connected to the mobile phone 4. For this reason, the plug 12 is provided with a plurality of terminals so that the core cables LL, LR, LG and the covered wire SS can be individually connected to the mobile phone 4. More specifically, in this embodiment, the plug 12 is provided with a 10-pin terminal. In FIG. 1, the 10-pin terminals are indicated by numerals 1 to 10.

  That is, the cable 10 is connected to the core cables LL and LR to which the hot side of the left channel audio signal and the hot side of the right channel audio signal are respectively assigned via the high frequency cutoff circuits 16 and 17 provided on the wiring board 14. Twelve fourth and fifth terminals 4 and 5 are respectively connected. In addition, the cable 10 is connected to the third, sixth, and tenth terminals 3, 6, and 10 of the plug 12 through the high-frequency cutoff circuit 18 provided on the wiring board 14. The The cable 10 has a covered wire SS connected to the first terminal 1.

  Here, the high-frequency cutoff circuits 16, 17 and 18 are circuits that prevent the high-frequency signal induced in the cables 6 and 10 from entering the mobile phone 4. Therefore, the high frequency cutoff circuits 16, 17 and 18 can be applied with an inductor element or the like whose impedance is increased by increasing the frequency. The third and sixth terminals 3 and 6 are connection detection terminals for detecting the connection of the relay cable 2 by the mobile phone 4. The mobile phone 4 corresponds to the third and sixth terminals 3 and 6. The connection of the relay cable 2 is detected by determining whether or not the terminal of the jack 13 to be connected is connected to the ground.

  The relay cable 2 is set so that the length of the cable 10 is an electrical length of approximately ¼ wavelength with respect to the center frequency in the television broadcast band of the UHF band. Thus, the relay cable 2 is configured to function as a quarter-wave monopole antenna when receiving a UHF band television broadcast.

  In contrast, the earphone 3 has a length obtained by adding the length of the cable 6 to the length of the relay cable 2 and an electrical length of approximately ¼ wavelength with respect to the center frequency in the television broadcast band of the VHF band. Is set to be Accordingly, the relay cable 2 and the earphone 3 are configured to function as a quarter-wave monopole antenna when receiving a VHF band television broadcast.

  The relay cable 2 has an impedance adjustment that adjusts the impedance between the core cables LR, LL, LG of the relay cable 2 and the coated wire SS at the wiring board 14 side end of the core cable LG assigned to the coated wire SS and the ground. Connection is made via the element 20. Here, the impedance element is an element that corrects the impedance between the core cables LL, LR, LG and the covered wire SS and sets the NULL point of the antenna gain by the covered wire SS to a frequency band in the vicinity of the reception frequency of the tuner 21. . In this embodiment, an element for adjusting the reactance between the core cable and the covered wire, more specifically, a 1 [pF] chip capacitor having excellent high frequency characteristics is applied to the impedance adjusting element 20.

  The mobile phone 4 is a mobile phone having a television broadcast receiving function. In the mobile phone 4, the antenna input terminal of the tuner 21 that receives the television broadcast is connected to the first terminal 1 of the jack 13. As a result, in the mobile phone 4, the high frequency signal induced in the covered wire SS of the relay cable 2 and the high frequency signal induced in the covered wire SS and the cable 6 of the earphone 3 are input to the tuner 21. Here, the high-frequency signal induced by the cable 6 of the earphone 3 is input to the tuner 21 through the covered wire SS by the coupling of the covered wire SS and the core wire cables LR, LL, and LG. As a result, the tuner A high frequency signal induced by the cable 6 of the covered wire SS and the earphone 3 is input to 21.

  Here, since the electrical lengths of the relay cable 2 and the earphone 3 are set as described above, in this case, when the tuner 21 receives television broadcasting in the UHF band, the covered wire SS of the relay cable 2 is used. Is used as a monopole antenna to receive broadcast waves. When receiving a television broadcast in the VHF band, a broadcast wave is received using the covered wire SS of the relay cable 2 and the cable 6 of the earphone 3 as a monopole antenna.

  The cellular phone 4 amplifies the right channel and left channel audio signals SAR and SAL obtained from the tuner 21 by the amplification circuits 22R and 22L, respectively, and then inputs the amplified signals to the built-in speaker 24 via the switching circuit 23.

  When the relay cable 2 is connected, the cellular phone 4 switches the operation of the switching circuit 23 by the controller 25, stops outputting the audio signals SAR and SAL to the built-in speaker 24, and jacks these audio signals SAR and SAL. 13 to the fourth and fifth terminals 4 and 5. Thus, when the relay cable 2 is connected, the mobile phone 4 provides the user with audio signals SAL and SAR through the earphone 3 instead of the built-in speaker 24.

  Here, in the mobile phone 4, the tenth terminal 10 of the jack 13 is connected to the ground. The controller 25 monitors the potential of the third or sixth terminal 3, 6 connected to the tenth terminal 10 by the relay cable 2, and when the third or sixth terminal 3, 6 becomes the ground potential. The operation of the switching circuit 23 is switched by determining that the relay cable 2 is connected.

(2) Operation of Embodiment In the above configuration, in this cellular phone system 1 (FIGS. 1 and 2), the tuner 21 is activated in response to a user operation, and the audio signal received by the tuner 21 SAL and SAR are output from the built-in speaker 24. When the relay cable 2 is connected to the mobile phone 4, the connection of the relay cable 2 is detected by the controller 25, and the audio signals SAL and SAR are output to the relay cable 2 instead of the built-in speaker 24.

  In the cellular phone system 1, the audio signals SAL and SAR are supplied to the cable 6 of the earphone 3 via the core cables LL and LR of the relay cable 2, and thereby the speakers 8L and 8R of the earphone 3 are received by the audio signals SAL and SAR. Is driven. In the cellular phone system 1, the audio signals SAL and SAR are thereby transmitted to the earphone 3 through the relay cable 2, and the sound of the broadcast wave received by the tuner 21 is provided to the user by the earphone 3.

  In the cellular phone system 1, various high frequency signals are transmitted to the cable 10 of the relay cable 2 and the cable 6 of the earphone 3 in a state where the audio signals SAL and SAR are transmitted to the earphone 3 through the relay cable 2 in this way. Will be induced.

  Here, in the mobile phone system 1, the cable 10 of the relay cable 2 that transmits the audio signals SAL and SAR is a multi-core coaxial cable surrounded by the covered wire SS, and the covered wire SS is connected to the open end on the earphone 3 side. Since the covered wire SS is connected to the antenna input terminal of the tuner 21 on the mobile phone 4 side, the high-frequency signal induced in the cable 6 of the earphone 3 becomes the core cables LR, LL, LG of the cable 10. Is coupled to the covered wire SS of the cable 10 and is input to the antenna input terminal of the tuner 21 via the covered wire SS.

  As a result, in this case, the earphone 3 and the relay cable 2 constitute a monopole antenna, and the tuner 21 receives the broadcast wave induced in the monopole antenna.

  Here, in the mobile phone system 1, the monopole antenna formed by the earphone 3 and the relay cable 2 is set to a length corresponding to the VHF band television broadcast wave, thereby receiving the VHF band television broadcast wave. In this case, a television broadcast is received by a monopole antenna using the earphone 3 and the relay cable 2.

  On the other hand, in the mobile phone system 1, the covered wire SS of the relay cable 2 is opened at the earphone 3 side, and the cable 10 of the relay cable 2 is set to a length corresponding to the television broadcast wave in the UHF band. Therefore, when a television broadcast wave in the UHF band is received, the covered wire SS of the relay cable 2 functions as a monopole antenna, and the television broadcast wave is received by the monopole antenna formed by the covered wire SS. become.

  However, when receiving the UHF band, the high-frequency signal induced in the covered wire SS leaks to the core cables LR, LL, LG due to the coupling of the core wires LR, LL, LG of the cable 10 and the covered wire SS. . As a result, the leaked high-frequency signal cancels out the electric field that induces the high-frequency signal in the covered wire SS, and the covered wire SS does not sufficiently function as an antenna. As a result, it is impossible to sufficiently suppress the radio communication wave in the nearby frequency band, and the antenna gain is reduced in a frequency band close to the frequency band of the radio communication wave.

  That is, FIG. 3A is a characteristic curve diagram showing the antenna gain reduction and the influence of the radio communication wave in the near frequency band. In FIG. 3 (A), symbols LH and LV indicate horizontal polarization and vertical polarization antenna input characteristics, respectively. FIGS. 3B and 3C are charts showing in detail the characteristics of the vertical polarization and horizontal polarization. The characteristics shown in FIG. 3 are characteristics when a high-frequency cutoff circuit 32 using a chip inductor is disposed in place of the impedance adjustment element 20 as shown in FIG. 4 in comparison with FIG. In the mobile phone system 31 of FIG. 4, the same components as those of the mobile phone system 1 of FIG.

  In this case, it can be seen that the gain is reduced in the vicinity of the frequency 770 [MHz] in the television broadcast band of the frequency 470 to 770 [MHz]. Further, the NULL point in the horizontally polarized wave is in the vicinity of the frequency 890 [MHz], and it can be seen that the radio communication wave of the cellular phone cannot be sufficiently suppressed. Accordingly, in this case, in the example shown in FIG. 4, it is necessary to provide a multistage filter 33 at the antenna input end of the tuner 21.

  As shown in FIG. 5, the deterioration of the suppression characteristic in the nearby frequency band is caused by the capacitive coupling between the core cables LR, LL, LG and the covered wire SS of the cable 10, and the core cables LR, LL, LG and earphones in the UHF band. This is caused by the fact that the third cable 6 functions as a stub of the monopole antenna by the covered wire SS. In FIG. 5, the capacitance due to the capacitive coupling is indicated by a symbol C.

  Therefore, in this embodiment, as shown in FIG. 6 in comparison with FIG. 5, the impedance adjustment element 20 connects the ends of the core cables LR, LL, LG and the covered wire SS to the mobile phone 4 side, and this impedance adjustment element 20 Thus, the impedance component between the core cables LR, LL, LG and the covered wire SS is adjusted, and the electrical length of the stub is corrected.

  Here, FIGS. 7A to 7C are characteristic curve diagrams and charts showing the antenna input characteristics according to this embodiment in comparison with FIGS. 3A to 3C. In the example of FIG. 7, it can be seen that when a capacitor is applied to the impedance adjustment element 20, the NULL point can be moved to the lower frequency side. Since FIG. 7 shows the antenna input characteristic according to this embodiment, the impedance adjusting element 20 is a 1 [pF] capacitor. In the example of FIG. 7, it can be seen that the antenna gain increases in the vicinity of the frequency 770 [MHz]. Further, the NULL point in the horizontally polarized wave is in the vicinity of the frequency 810 [MHz], and it can be seen that the radio communication wave of the mobile phone can be sufficiently suppressed. Therefore, the multi-stage filter 33 required in the example of FIG. 4 can be omitted or the configuration can be simplified. For example, when the surface acoustic wave filter constituting the multistage filter is omitted, the loss due to the filter can be reduced by about 5 to 10 [dB], and as a result, the reception sensitivity of the television broadcast wave can be improved. .

  On the other hand, FIGS. 8A to 8C are compared with FIGS. 3A to 3C and FIGS. 7A to 7C in that the impedance adjustment element 20 has a 33 nH inductor. It is a characteristic curve figure and chart which show the case where is applied. In this case, it can be seen that the NULL point can be moved to the higher frequency side.

(3) Effects of the embodiment According to the above configuration, when an audio signal is transmitted by the core wire of the multi-core coaxial cable and the antenna is configured by the coated wire, the impedance between the core wire and the coated wire is adjusted, and the antenna gain By setting the null point to the wireless communication wave band in the nearby frequency band, the wireless communication wave in the nearby frequency band can be sufficiently suppressed. Therefore, the reception performance can be improved by reducing the interference caused by the radio communication wave in the near frequency band. In addition, the configuration of the tuner antenna input stage can be simplified, and the resistance of the tuner can be improved. Further, the antenna gain can be improved in a frequency band close to the radio communication wave.

  In addition, by adjusting the impedance between the core wire and the coated wire by the impedance adjustment element, the impedance adjustment element can be set in various ways to freely set the null point of the antenna gain. It can be set with a high degree of freedom.

  Further, by applying a capacitor to this impedance adjusting element, the NULL point of the antenna gain can be moved to the lower frequency side.

  In the cellular phone system of this embodiment, an inductor is applied to the impedance adjustment element 20. That is, in the mobile phone system of this embodiment, the length of the relay cable is set so that the NULL point of the UHF band when the impedance adjusting element 20 is not provided is within the band of the television broadcast wave. In addition, an inductor is applied to the impedance adjustment element 20 to move the NULL point to the radio communication wave band in the near frequency band.

  Even if an inductor is applied to the impedance adjusting element as in this embodiment, the same effect as in the first embodiment can be obtained.

  FIG. 9 is a connection diagram showing the mobile phone system according to the third embodiment of the present invention in comparison with FIG. In this cellular phone system 41, a varicap 42 is applied to the impedance adjustment element 20. In the mobile phone system 41, a DC voltage output from the variable power supply 44 is applied to the coated wire SS side of the varicap 42 via an inductor 43 that cuts off a high-frequency signal. Thus, the cellular phone system 41 changes the capacity of the varicap 42 by varying the DC voltage output from the variable power supply 44 in accordance with the frequency of data communication and the reception frequency of television broadcasting. As a result, the cellular phone system 41 sets the NULL point to an appropriate frequency according to the frequency of data communication and the reception frequency of television broadcasting, thereby further improving the antenna performance.

  Even if a varicap is applied to the impedance adjusting element as in this embodiment, the same effect as in the first embodiment can be obtained.

  Further, in this embodiment, the capacity of the varicap can be varied in accordance with the frequency of data communication and the reception frequency of television broadcasting to set the NULL point to an appropriate frequency, thereby further improving the antenna performance.

  FIG. 10 is a connection diagram showing the mobile phone system according to the fourth embodiment of the present invention in comparison with FIG. The cellular phone system 51 sets a NULL point in the band of the radio communication wave in the near frequency band by setting the capacity of the cable 10 provided in the relay cable 2.

  That is, the unit length capacity C of the coaxial cable is expressed as follows: C = 2πε / log (D / d) using the diameter d of the core cable, the inner diameter D of the coated wire, and the dielectric constant ε of the insulator between the core cable and the coated wire. It is represented by Therefore, in this embodiment, the NULL point is set by varying all or part of the diameter d of the core wire cable, the inner diameter D of the coated wire, and the dielectric constant ε of the insulator.

  Even if the impedance between the core wire and the covered wire is adjusted by adjusting the capacitance of the multi-core coaxial cable constituting the relay cable as in this embodiment, the same effect as in the first embodiment can be obtained.

  FIG. 11 is a connection diagram showing a mobile phone system according to a fifth embodiment of the present invention in comparison with FIG. In the cellular phone system 61, the impedance adjustment element 20 is switched between the capacitor 64 and the inductor 65 by switching the connection by the switch circuits 62 and 63.

  In the cellular phone system 61, the impedance adjustment element 20 is switched between the capacitor 64 and the inductor 65 in accordance with the frequency of data communication and the reception frequency of television broadcast, whereby the frequency of data communication and the reception frequency of television broadcast are obtained. Accordingly, the NULL point is set to an appropriate frequency to further improve the performance of the antenna.

  Even if the impedance adjusting element is switched as in this embodiment, the same effect as in the third embodiment can be obtained.

  In the above-described embodiment, the case of receiving a television broadcast wave has been described. However, the present invention is not limited to this, and can be widely applied to the case of receiving various broadcast waves.

  In the above-described embodiment, the case where the relay cable is detachably connected using the connector and the earphone is further connected has been described. However, the present invention is not limited to this, and the so-called built-in relay cable is difficult to attach and detach. And it can apply widely also when connecting an earphone.

  In the above-described embodiments, the case where the earphone cable is used as an antenna has been described. However, the present invention is not limited to this, and audio signals, video signals, and the like can be transmitted to various external devices via a signal transmission cable. The present invention can be widely applied when various signals are transmitted, and further when power is transmitted to an external device via a power transmission cable.

  In the above-described embodiments, the case where the present invention is applied to a mobile phone system has been described. However, the present invention is not limited thereto, and is widely applied to various receiving devices such as a portable music player having a broadcast wave receiving function. Can be applied.

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

1 is a connection diagram illustrating a mobile phone system according to a first embodiment of the present invention. 1 is a perspective view illustrating a mobile phone system according to a first embodiment of the present invention. It is a figure with which it uses for description of the characteristic deterioration of the antenna in the mobile telephone system of FIG. FIG. 4 is a connection diagram illustrating a mobile phone system used for the description of FIG. 3. FIG. 5 is a connection diagram for explaining an antenna in the mobile phone system of FIG. 4. FIG. 6 is a connection diagram for explaining an antenna in the mobile phone system of FIG. 1 in comparison with FIG. 5. It is a figure which shows the characteristic of the antenna in the mobile telephone system of FIG. It is a figure which shows the characteristic of the antenna at the time of applying an inductor to an impedance adjustment element. It is a connection diagram which shows the mobile telephone system of Example 3 of this invention. It is a connection diagram which shows the mobile telephone system of Example 4 of this invention. It is a connection diagram which shows the mobile telephone system of Example 5 of this invention. It is a characteristic curve figure which shows the frequency allocation of a UHF band.

Explanation of symbols

1, 31, 41, 51, 61 …… Mobile phone system, 2 …… Relay cable, 3 …… Earphone, 4… Mobile phone, 6, 10 ... Cable, 7, 12 ... Plug, 8R, 8L… ... Speaker, 11, 13 ... Jack, 20 ... Impedance adjustment element, 21 ... Tuner, 42 ... Varicap, 43, 65 ... Inductor, 64 ... Capacitor, LL, LR, LG ... Core cable, SS …… Covered wire

Claims (9)

A main unit that transmits a desired signal to and from an external device and receives a broadcast wave by a built-in tuner;
One end is connected to the main body device, the other end is connected to the external device, the signal is transmitted by a core wire, the external device side end of the coated wire surrounding the core wire is an open end, and the coated wire The main unit side has a relay cable connected to the antenna input end of the tuner,
In order to suppress the adjacent frequency band adjacent to the tuner reception frequency band that affects the reception characteristics of the broadcast wave by the tuner, by setting the impedance between the core wire and the covered wire of the relay cable, The null point of the gain of the antenna by the covered wire is set to a frequency band close to the reception frequency band of the tuner,
Receiver device. The receiving device according to claim 1, wherein an impedance adjustment element that corrects an impedance between the core wire and the covered wire of the relay cable is provided between the core wire and the covered wire at the main device side end. The receiving device according to claim 2, wherein the impedance adjusting element is a capacitor. The receiving device according to claim 2, wherein the impedance adjustment element is an inductor. The external device is an earphone;
The receiving device according to claim 1, wherein the signal is an audio signal that drives the earphone. The receiving device according to claim 1, wherein the relay cable is detachably connected to the main body device by a connector. The receiving device according to claim 1, wherein the external device is detachably connected to the relay cable by a connector. One end is connected to the main unit,
The other end is connected to an external device,
A signal is transmitted between the main device and the external device by a core wire,
The external device side end of the covered wire surrounding the core wire is an open end,
The main unit side of the covered wire is connected to an antenna input end of a tuner provided in the main unit,
In order to suppress a nearby frequency band that is close to the reception frequency band of the tuner, which affects the deterioration of the reception characteristics of the broadcast wave by the tuner, by setting the impedance between the core wire and the covered wire, An antenna in which a null point of the gain of the antenna is set to a frequency band close to a reception frequency band of the tuner. One end is connected to the main unit via a connector,
The other end is connected to the earphone via the connector,
An audio signal output from the main unit via a core wire is transmitted to the earphone;
The external device side end of the covered wire surrounding the core wire is an open end,
The main unit side of the covered wire is connected to an antenna input end of a tuner provided in the main unit,
In order to suppress a nearby frequency band that is close to the reception frequency band of the tuner, which affects the deterioration of the reception characteristics of the broadcast wave by the tuner, by setting the impedance between the core wire and the covered wire, A relay cable in which a null point of the antenna gain is set to a frequency band close to the reception frequency band of the tuner.

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