JP5187080B2 - Receiver - Google Patents

Description

  The present invention relates to a receiving apparatus, and can be applied to, for example, a portable music player capable of receiving digital television broadcasting and FM broadcasting. In the present invention, a cable for signal and power transmission is a multi-core coaxial cable, the external device side has a covered wire as an open end, the main body device side is connected to the core wire cable, and the main body device has a filter. By connecting the coated wire to the high-band and low-band tuners via a circuit, it is possible to reliably avoid broadcasts in multiple frequency bands without using a switch circuit and effectively avoiding an increase in device size and design deterioration. To be able to receive.

  Conventionally, Japanese Patent Laid-Open No. 10-93473, Japanese Patent Laid-Open No. 2002-298802, Japanese Patent Laid-Open No. 2005-20381, etc. switch the output of an antenna with a switch circuit and use a single antenna with a plurality of tuners. It is disclosed.

  That is, FIG. 28 is a diagram illustrating a receiving system to which the disclosed technique is applied. In the receiving system 1, the output of the antenna 2 is input to the switch circuit 3. The receiving system 1 switches the operation of the switch circuit 3 according to a predetermined control signal S1 and selectively inputs the output of the antenna 2 to the antenna input terminals of the high band tuner 4 and the low band tuner 5. Here, the high band tuner 4 is, for example, a tuner that receives a digital television broadcast. The low band tuner 5 is a tuner that receives FM broadcasts. Note that matching circuits (M) 6 and 7 are appropriately disposed between the antenna input terminals of the high-band tuner 4 and the low-band tuner 5 and the switch circuit 3, respectively.

Conventionally, JP 2006-25392 A discloses a configuration of an earphone antenna that uses an earphone cable as an antenna.
JP-A-10-93473 JP 2002-298802 A Japanese Patent Laid-Open No. 2005-20281 JP 2006-25392 A

  However, the configuration of FIG. 28 has various problems due to the provision of the switch circuit. Specifically, in the configuration of FIG. 28, there is a problem that sensitivity is lowered due to insertion loss of the switch circuit. In addition, there is a problem that the configuration becomes complicated, power consumption increases, and further, the mounting space increases.

  In the configuration of FIG. 28, when a rod antenna is applied to the antenna 2, an antenna 2 having a length of 75 [cm] corresponding to a quarter wavelength of the frequency is 100 [MHz] in the FM broadcast band. I need it. In this case, in the UHF band (frequency 470 to 770 [MHz]) related to digital television broadcasting, the antenna 2 having a length of 15 [cm] corresponding to a quarter wavelength of the frequency 500 [MHz] is required. .

  Here, if the length of the antenna 2 is set to 75 [cm] necessary for the FM broadcast band, the portable device has a problem that the device is remarkably enlarged and the design is remarkably deteriorated. On the contrary, if the length of the antenna 2 is set to 15 [cm] necessary for the UHF band, it becomes difficult to secure sufficient reception power in the FM broadcast, and the FM broadcast cannot be received.

  Accordingly, it is required that broadcast waves can be reliably received in a plurality of frequency bands without using a switch circuit.

  Here, as a method for receiving broadcast waves in a plurality of frequency bands without using a switch circuit, as shown in FIG. 29 in comparison with FIG. 28, dedicated antennas 2A and 2B for the high band tuner 4 and the low band tuner 5, respectively. A method of providing 2B is conceivable. In the receiving system 8, various problems caused by providing the switch circuit can be solved at once.

  However, in the configuration of FIG. 29, there is a problem that the receiving device becomes large, and in the case of a mobile device, the portability is remarkably deteriorated and the design is impaired.

  A method of using a distributor such as a Wilkinson coupler instead of the switch circuit is also conceivable, but this method also has a problem that sensitivity is lowered due to insertion loss.

  The present invention has been made in consideration of the above points, and can effectively receive broadcast waves in a plurality of frequency bands by effectively avoiding the enlargement of the device and the deterioration of the design without using a switch circuit. It is intended to propose a receiving apparatus that can

According to the present invention, there is a main body device, a relay cable for transmitting signals and / or power between the main body device and the external device, and an external antenna provided in the main body device ,
The relay cable is
A plurality of core cables including a ground cable, and a covered wire formed of a conductor connected to the ground cable on the main unit side and covering the plurality of core cables, and functions as a coaxial transmission line is a multi-core coaxial cable,
Transmitting the signal and / or power by the core cable,
The external device side end of the covered wire is an open end, and the covered wire functions as a part of the antenna in cooperation with the external antenna,
Before Symbol main unit,
A high-band tuner that receives broadcast waves of a predetermined frequency band;
A low-band tuner in which the reception frequency band is set to a low frequency with respect to the reception frequency band of the high-band tuner,
The covered wire is connected to the input end, an output signal is output to the high band tuner, the reception frequency band of the high band tuner is set as a pass band, and the reception frequency band of the low band tuner is set as a cutoff band A high-band filter,
A low band in which the covered wire is connected to an input end, an output signal is output to the low band tuner, a reception frequency band of the low band tuner is set as a pass band, and a reception frequency band of the high band tuner is set as a cutoff band With side filter
A receiving device is provided.

  According to the configuration of the first aspect, when the end of the covered wire on the external device side is an open end and the end of the covered wire on the main device side is connected to the core cable, the covered wire is an antenna in the frequency band corresponding to the length of the covered wire. Function as. In a frequency band lower than this frequency band, the cable on the external device side connected to the core cable and the relay cable function as an antenna. Thus, it is possible to configure an antenna of two frequency bands by effectively using the cable between the external devices. Furthermore, if a covered wire is connected to a high band tuner and a low band tuner through a high band filter and a low band filter in which a pass band and a stop band are set according to the configuration of claim 1, a switch circuit is used. Instead, a single antenna can be commonly used by a plurality of tuners, and broadcast waves can be received in frequency bands corresponding to the high band tuner and the low band tuner. As a result, it is possible to reliably receive broadcast waves in a plurality of frequency bands while effectively avoiding an increase in size and design deterioration without using a switch circuit.

  According to the present invention, it is possible to reliably receive broadcast waves in a plurality of frequency bands by effectively avoiding the enlargement of the device and the deterioration of the design without using a switch circuit.

  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 Modification <First Embodiment>
[Configuration of the embodiment]
[Principle configuration]
FIG. 2 is a block diagram showing the basic configuration of the receiving system according to the first embodiment of the present invention in comparison with FIG. In the reception system 11, the output signal of the antenna 14 is terminated by a high pass filter (HPF) 12 and a low pass filter (LPF) 13. The output signals of the high pass filter 12 and the low pass filter 13 are input to the antenna input terminals of the high band tuner 15 and the low band tuner 16, respectively.

  Here, the low-band tuner 16 to which the low-pass filter 13 is connected is a tuner that receives a lower frequency band than the high-band tuner 15 to which the high-pass filter 12 is connected. Specifically, the high-band tuner 15 is a tuner that receives a digital television broadcast whose reception frequency band is a UHF band (frequency 470 to 770 [MHz]), for example. The low-band tuner 16 is a tuner that receives an FM broadcast whose reception frequency band is a VHF band (frequency 80 to 110 [MHz]).

  In the high-pass filter 12, the reception frequency band of the high-band tuner 15 is a pass band, and the reception frequency band of the low-band tuner 16 is set as a cutoff band. On the contrary, in the low-pass filter 13, the reception frequency band of the high-band tuner 15 is set as the cutoff band, and the reception frequency band of the low-band tuner 16 is set as the pass band. Further, the high-pass filter 12 and the low-pass filter 13 are set so that the impedance (input impedance) viewed from the input side end increases as the frequency becomes farther from the cutoff frequency in the cutoff band. Note that the high-pass filter 12 and the low-pass filter 13 may also serve as a matching circuit with the antenna 14.

  As a result, as indicated by an arrow A in FIG. 3, in the reception system 11, the high frequency signal from the antenna 14 in the reception frequency band of the high band tuner 15 is prevented from flowing into the low pass filter 13 side, and the high pass filter 12 side Only flows into As a result, in this frequency band, the output signal of the antenna 14 can be input only to the high band tuner 15 to receive broadcast waves.

  Further, as indicated by an arrow B in FIG. 4, the high-frequency signal from the antenna 14 in the reception frequency band of the low-band tuner 16 is prevented from flowing into the high-pass filter 12 side and flows only into the low-pass filter 13 side. As a result, in this frequency band, the output signal of the antenna 14 can be input only to the low-band tuner 16 to receive broadcast waves.

  As a result, in the receiving system 11, one antenna 14 can be used by a plurality of high band tuners 15 and low band tuners 16 without providing a switch circuit, and various inconveniences when a switch circuit is provided are effectively avoided. be able to.

  If the passbands of the high-pass filter 12 and the low-pass filter 13 overlap even partly, the antenna output is distributed to two systems in this overlapping frequency band. Specifically, this is the case when the cutoff frequencies of the high-pass filter 12 and the low-pass filter 13 are set to 50 [MHz] and 900 [MHz], respectively. Therefore, the filter of each tuner needs to be configured to prevent the antenna output from flowing in the reception frequency band of the other tuner and to allow the antenna output to flow in the reception frequency band of its own tuner. Therefore, as long as this condition is satisfied, a band pass filter may be applied instead of the high pass filter and the low pass filter.

  Further, in this receiving system 11, as shown in FIG. 5 by comparison with FIG. 2, the antenna 14 is provided by an earphone antenna having portions 14A and 14B that function as antennas in the reception frequency bands of the high band tuner 15 and the low band tuner 16, respectively. Configure. As a result, the receiving system 11 prevents portability and design deterioration.

[Specific configuration]
FIG. 6 is a perspective view showing a receiving system according to the specific configuration of the first exemplary embodiment of the present invention. In the receiving system 11, an earphone 24 is connected to a main body device 23 via a relay cable 22.

  Here, as shown in FIG. 7, the earphone 24 has a three-pin plug 27 connected to one end of a cable 26, and right and left channel speakers 28 </ b> R and 28 </ b> L connected to the other end of the cable 26. More specifically, the earphone 24 is a three-wire type in which a parallel two-wire cable extending from the right channel and left channel speakers 28R and 28L respectively shares a ground with the right channel and left channel audio signals. Connected to a flat cable. As a result, the earphone 24 is connected to the plug 27 after the cables extending from the right and left channel speakers 28R and 28L are bundled together. In this embodiment, the parallel two-wire cables extending from the right channel and left channel speakers 28R and 28L are set to lengths of 100 [mm] and 450 [mm], respectively. The length from the plug 7 to the left channel speaker 28L is set to 1200 [mm].

  As shown in FIG. 8, the relay cable 22 is provided with a jack 31 for connecting the plug 27 of the earphone 24 at one end of the cable 30 and a plug 32 at the other end of the cable 30.

  Here, as shown in FIG. 9, the cable 30 is a multi-core coaxial cable. The cable 30 is formed by bundling a plurality of core wire cables LL, LR, LG, and then sequentially covering with an insulating layer 35 made of polyethylene, a covered wire SS, and an outer skin 36 made of an elastomer. The covered wire SS is composed of a copper mesh wire.

  The main unit 23 is a portable music player having a receiving function for digital television broadcasting and FM broadcasting. The main unit 23 is provided with a jack 33 for connecting the plug 32 of the relay cable 22 on the bottom surface.

  FIG. 1 is a connection diagram showing in detail the receiving system 11 of FIG. In the relay cable 22, the core cables LL, LR, and LG are assigned to the common ground for the hot side of the left channel audio signal SAL, the hot side of the right channel audio signal SAR, the left channel audio signal SAL, and the right channel audio signal SAR, respectively. . In the relay cable 22, the earphone side ends of the core cables LL, LG, and LR are connected to the corresponding terminals 31 </ b> L, 31 </ b> G, and 31 </ b> R of the jack 31. Further, the main body side ends of the core cables LL, LG, and LR are connected to corresponding terminals of the plug 32.

  Further, the relay cable 22 has an open end at which the earphone side end of the covered wire SS is not connected to any part. Moreover, the main body side end of the covered wire SS is connected to the core wire cable LG assigned to the ground.

  The length LL1 of the relay cable 22 is set to a length of about ¼ wavelength with respect to the center frequency of the digital television broadcast band. Also, with this length setting, in this receiving system 11, the length LL2 from the plug 32 to the speaker 28L is set to a length of about ¼ wavelength with respect to the center frequency of FM broadcasting.

  The main unit 23 includes a high band tuner 41 that receives digital television broadcasts and a low band tuner 42 that receives FM broadcasts. The high band tuner 41 and the low band tuner 42 perform digital television broadcasts and FM broadcasts on the left. The audio signals SAL and SAR of the channel and the right channel are acquired. In the main unit 23, the terminal of the jack 33 corresponding to the core cable LG assigned to the ground is grounded via a high-frequency cutoff circuit 43 that cuts off a high-frequency signal. The audio signals SAL and SAR obtained from the high band tuner 41 and the low band tuner 42 are output to the terminals of the jack 33 corresponding to the core cables LL and LR via the high frequency cutoff circuits 44 and 45, respectively. Accordingly, the main body device 23 is configured to be able to listen to the sound of the television broadcast and the sound of the FM broadcast via the earphone 24. Note that the high frequency cutoff circuits 43 to 45 are made of, for example, ferrite beads.

  The main body device 23 is provided with a high-pass filter 47 and a low-pass filter 48 at the antenna input terminals of the high-band tuner 41 and the low-band tuner 42. Here, the high-pass filter 47 and the low-pass filter 48 correspond to the high-pass filter 12 and the low-pass filter 13 described above with reference to FIG. Therefore, in the high pass filter 47, the reception frequency band of the high band tuner 41 is a pass band, and the reception frequency band of the low band tuner 42 is a cutoff band. In the low-pass filter 48, the reception frequency band of the low-band tuner 42 is a pass band, and the reception frequency band of the high-band tuner 41 is a cut-off band. The high-pass filter 47 and the low-pass filter 48 are set so that the input impedance increases as the frequency increases away from the cutoff frequency in the cutoff band.

  More specifically, the high-pass filter 47 terminates the input signal by a series circuit of the capacitor C1 and the inductor L1, and inputs the connection midpoint of the capacitor C1 and the inductor L1 to the antenna input terminal of the high-band tuner 41 by the coupling capacitor C2. To do. The low-pass filter 48 terminates an input signal by a series circuit of an inductor L2 and a capacitor C3, and inputs a connection midpoint between the inductor L2 and the capacitor C3 to an antenna input terminal of the low-band tuner 42 by a coupling capacitor C4.

  In the main unit 23, the jack 33 side end of the high-frequency cutoff circuit 43 that grounds the grounding core wire cable LG is commonly connected to the input ends of the high-pass filter 47 and the low-pass filter 48 via the inductor L3. As a result, in the receiving system 11, when receiving digital television broadcasting, the covered wire SS functions as a ¼ wavelength monopole antenna, and the high-band tuner 41 uses the high-frequency signal induced by the covered wire SS. Receive digital television broadcasts. When receiving FM broadcasting, the cable 26 and the relay cable 22 of the earphone 24 are made to function as a ¼ wavelength monopole antenna, and the low-band tuner 42 is generated by the high-frequency signal induced by the cable 26 and the relay cable 22 of the earphone 24. Receive FM broadcast.

  The inductor L3 provided at the input stage of the high-pass filter 47 and the low-pass filter 48 constitutes a matching circuit for the high-band tuner 41 together with the high-pass filter 47, and constitutes a matching circuit for the low-band tuner 42 together with the low-pass filter 48.

[Operation of the embodiment]
In the above configuration, in the receiving system 11 (FIGS. 1 and 6), the high band tuner 41 or the low band tuner 42 starts up in response to a user operation, and the high band tuner 41 or the low band tuner 42 performs digital TV. John broadcast or FM broadcast audio signals SAL and SAR are acquired.

  In the receiving system 11, the audio signals SAL and SAR are supplied to the cable 26 of the earphone 24 via the core cables LL, LR and LG of the relay cable 22, and the speakers 28L and 28R of the earphone 24 are transmitted by the audio signals SAL and SAR. Driven. In the receiving system 11, the audio signals SAL and SAR are thereby transmitted to the earphone 24 via the relay cable 22, and the sound of the broadcast wave received by the high band tuner 41 and the low band tuner 42 is provided to the user by the earphone 24.

  In the receiving system 11, various high-frequency signals are induced in the cable 30 of the relay cable 22 and the cable 26 of the earphone 24 in a state where the audio signals SAL and SAR are transmitted to the earphone 24 through the relay cable 22 in this way. Is done.

  Here, among the high frequency signals in the reception frequency band of the high band tuner 41, the high frequency signal induced by the cable 26 of the earphone 24 is input to the main body device 23 via the relay cable 22. In addition, the relay cable 22 has core wires LR, LG, LL connected to the cable 26 of the earphone 24, and these core wires LR, LG, LL are covered with a covered wire SS, so that it functions as a coaxial transmission line. The high frequency signal induced by the cable 26 of the earphone 24 is transmitted.

  However, in the relay cable 22, the length LL1 of the covered wire SS is set to a length of ¼ wavelength with respect to the center frequency of this frequency band, and the core wire cable LG and the covered wire SS are connected at the end on the main body device 23 side. By being connected, the impedance as the coaxial transmission line becomes infinite in the reception frequency band of the high-band tuner 41. Therefore, the relay cable 22 functions so as not to transmit the high-frequency signal in the frequency band flowing from the cable 26 of the earphone 24 to the main body device 23.

  As a result, in the reception system 11, only the covered wire SS of the relay cable 22 functions as an antenna in the reception frequency band of the high-band tuner 41, and a 1/4 wavelength monopole antenna is configured by the covered wire SS. It will be. In the receiving system 11, the high-frequency signal induced by the monopole antenna is input to the main body device 23 through the plug 32 and the jack 33 in order.

  On the other hand, in the reception frequency band of the low-band tuner 42, the relay cable 22 does not harm the transmission of the high-frequency signal induced by the cable 26 of the earphone 24. Therefore, the high frequency signal induced by the cable 26 of the earphone 24 in this reception frequency band is input to the main body device 23 through the relay cable 22, the plug 32, and the jack 33 in order.

  In the transmission process in the relay cable 22, the high-frequency signal in the reception frequency band is coupled with the covered wire SS and the core wire cable LG, and further connected with the covered wire SS and the core wire cable LG at the root portion of the plug 32. The high frequency signal induced by the cable 26 of the earphone 24 is added to the high frequency signal induced in the covered wire SS. As a result, in the reception system 11, the cable 26 of the earphone 24 and the relay cable 22 function as an antenna in the reception frequency band of the low-band tuner 42. In this case, a ¼ wavelength monopole antenna is formed in the reception frequency band of the low-band tuner 42, and a high-frequency signal induced by this monopole antenna is input to the main unit 23 via the plug 32 and the jack 33 in this order. Is done.

  As a result, in this receiving system 11 (see FIG. 4), the portions functioning as the antennas of the high band tuner 41 and the low band tuner 42 are respectively formed by the covered wire SS of the relay cable 22 and the cable 26 and the relay cable 22 of the earphone 24. Will be composed. Further, the high-frequency signals induced at these parts are collectively input to the main unit 23. Thereby, in this receiving system 11, it is not necessary to provide an antenna separately, and it is possible to effectively avoid an increase in size and to prevent portability and design deterioration. Further, since the cable 26 and the relay cable 22 of the earphone 24 function as antennas, it is possible to prevent design deterioration and portability deterioration when a rod antenna is provided.

  In the main unit 23, the high-frequency signal input from the relay cable 22 is terminated by the high-pass filter 47 and the low-pass filter 48 through the inductor L3. The output signals of the high pass filter 47 and the low pass filter 48 are input to a high band tuner 41 and a low band tuner 42, respectively.

  Here, in the high-pass filter 47 and the low-pass filter 48 (see FIGS. 2 and 3), since the reception frequency band of the high-band tuner 41 is set to the pass band and the cutoff band, respectively, the high-frequency signal in the frequency band is The signal is input only to the high band tuner 41 through the high pass filter 47. In the high-pass filter 47 and the low-pass filter 48, since the reception frequency band of the low-band tuner 42 is set to the cut-off band and the pass band, respectively, the high-frequency signal in the frequency band passes through the low-band filter 48 side. Only entered in

  As a result, in the receiving system 11, it is possible to receive a desired broadcast wave by using the earphone antenna by the cable 26 of the earphone 24 and the relay cable 22 with the plurality of tuners 41 and 42.

  Further, in this receiving system 11, the input impedances of the high-pass filter 47 and the low-pass filter 48 are set to a characteristic that increases as the distance from the cutoff frequency increases in the cutoff band. In the pass band of the high-pass filter 47, the high-frequency signal flowing out to the high-pass filter 47 and the low-pass filter 48 is set to be almost negligible.

  More specifically, the high-pass filter 47 grounds the input signal through the capacitor C1 and the inductor L1 in order, and the connection midpoint between the capacitor C1 and the inductor L1 is connected to the high-band tuner 41 via the coupling capacitor C2. Connected to the input terminal. Here, the coupling capacitor C2 is set to a sufficiently large capacity, so that the high-pass filter 47 becomes substantially equal to a configuration in which the input impedance of the high-band tuner 41 is connected in parallel to the inductor L1. As a result, the high-pass filter 47 is set so that the input impedance increases as the frequency decreases, and the high-frequency signal from the antenna hardly flows in the pass band of the low-pass filter 48.

  The low-pass filter 48 connects the input signal to the ground via the inductor L2 and the capacitor C3 in order, and the midpoint of connection between the inductor L2 and the capacitor C3 is connected to the input terminal of the low-band tuner 42 via the coupling capacitor C4. Is done. Here, also in this case, the coupling capacitor C4 is set to a sufficiently large capacity, so that the low-pass filter 48 is substantially equal to the configuration in which the input impedance of the low-band tuner 42 is connected in parallel to the capacitor C3. . As a result, the low-pass filter 48 is set so that the input impedance increases as the frequency increases, and the high-frequency signal from the antenna hardly flows in the pass band of the high-pass filter 47.

  As a result, in this receiving system 11, the earphone antenna by the cable 26 of the earphone 24 and the relay cable 22 is used by the plurality of tuners 41 and 42 to receive a desired broadcast wave, and the loss of the high frequency signal flowing from the antenna is lost. Can be prevented. As a result, various problems when the switch circuit is provided can be effectively avoided. That is, the reduction in sensitivity can be prevented by reducing the insertion loss. In addition, by simply providing a filter, one tuner can be used in common by the two tuners 41 and 42, thereby simplifying the configuration and preventing an increase in power consumption. Further, an increase in mounting space can be reduced.

  FIG. 10 is a characteristic curve diagram showing antenna characteristics in the UHF band of the reception system 11. In FIG. 10, symbols LV and LH are measurement results of vertical polarization and horizontal polarization. 11 and 12 are tables showing the measurement results of FIG. 10 in detail. 13 to 15 are characteristic curve diagrams showing the antenna characteristics in the VHF band of the reception system 11 in comparison with FIGS. 10 to 12. FIGS. 16 to 18 are characteristic curve diagrams showing antenna characteristics in the UHF band of the reception system 11 when only the relay cable 22 is connected in comparison with FIGS. 10 to 12. Thus, it can be seen that even if the earphone 24 is connected to the relay cable 22, the deterioration of the characteristics can be effectively avoided. It can also be seen that sufficient antenna power can be secured even in the VHF band.

  FIGS. 19 to 21 are characteristic curve diagrams showing characteristics of the rod antenna for the UHF band in comparison with FIGS. 10 to 12. From the comparison of the measurement results of FIGS. 19 to 21 and the measurement results of FIGS. 10 to 12, it can be seen that the reception system 11 can ensure a gain substantially equivalent to that of the rod antenna.

  22 to 27 show the measurement results when the relay cable 22 is omitted and only the cable 26 of the earphone 24 is used as an antenna in comparison with FIGS. 10 to 12. In this case, the cable length of the earphone 24 is sufficiently longer than the wavelength in the UHF band. As a result, when the frequency corresponding to the cable length of the earphone 24 is set as a fundamental frequency, a broadcast wave is received at a higher harmonic frequency of the fundamental frequency in the UHF band. As a result, the characteristics are deteriorated in the UHF band, and in the measurement result of FIG. 22, the deterioration of the characteristics is noticeably observed at the frequency of 470 to 500 [MHz]. However, in this embodiment, it is possible to effectively avoid the deterioration of characteristics caused by such harmonics.

<Modification>
In the above-described embodiment, the case where the main body device side end of the covered wire is directly connected to the core wire cable has been described. However, the covered wire and the core wire cable need only be connected with a sufficiently low impedance at least in the reception frequency band of the main device, and may be connected via a capacitor, for example.

  Moreover, in the above-mentioned embodiment, the case where the main body apparatus side end of a covered wire was connected to the core wire cable allocated to the earth was described. However, the present invention is not limited to this, and the main body device side end of the covered wire may be connected to another core wire cable, and further, the main body device side end of the covered wire may be connected to a plurality of core wire cables. Also good. When connecting the main unit side end of the coated wire to multiple core cables, connect the core cable and the coated wire via a small-capacitance capacitor, or connect multiple core cables to each other. It is necessary not to hinder the transmission of signals assigned to the cable, and to connect a plurality of core cables to the main unit side end of the covered wire with sufficiently low impedance in the reception frequency band of the main unit. .

  In the above-described embodiment, the case where a high-pass filter and a low-pass filter are configured by a series circuit of a capacitor and an inductor has been described. However, the present invention is not limited to this, and high-pass filters and low-pass filters having various configurations can be widely applied.

  In the above-described embodiment, the case where the broadcast wave is received by the two tuners of the high band tuner and the low band tuner has been described. However, the present invention is not limited to this, and can be widely applied to a case where broadcast waves are received by a plurality of tuners, such as a case where broadcast waves are received by three tuners.

  In the above-described embodiment, the case where the length of the covered wire, the length of the covered wire, and the length of the cable of the earphone is set to a length corresponding to the digital television broadcast wave and the FM broadcast wave, respectively, has been described. However, the present invention is not limited to this, and can be widely applied when receiving various types of broadcast waves.

  In the above-described embodiment, the case where the earphone and the relay cable are detachably connected using the connector has been described. However, the present invention is not limited to this, and the earphone and the relay cable can be easily connected by a so-called built-in connection. It can also be widely applied to.

  In the above-described embodiment, the case where the cable for transmitting the audio signal functions as an antenna has been described. However, the present invention is not limited to this, and various analog signals other than audio signals, cables that transmit digital signals, and cables that transmit power may function as antennas.

  In the above-described embodiments, the case where the present invention is applied to a reception system using a portable music player has been described. Can be widely applied to the device.

  The present invention can be applied to, for example, a portable music player that can receive digital television broadcasting and FM broadcasting.

It is a connection diagram which shows the receiving system which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the basic composition of the receiving system which concerns on this invention. It is a block diagram with which it uses for description at the time of high band tuner use in the receiving system of FIG. FIG. 3 is a block diagram for explanation when a low-band tuner is used in the reception system of FIG. 2. It is a block diagram with which it uses for description of the antenna used with the receiving system of FIG. 1 is a perspective view showing a receiving system according to a first embodiment of the present invention. It is a figure which shows the earphone in the receiving system of FIG. It is a figure which shows the relay cable in the receiving system of FIG. It is a figure where it uses for description of the multi-core coaxial cable used for the relay cable of FIG. It is a characteristic curve figure which shows the characteristic of the antenna in the UHF band of the receiving system 11 of FIG. 11 is a chart showing in detail the characteristics of vertical polarization in the measurement result of FIG. 11 is a chart showing in detail the characteristics of horizontal polarization in the measurement result of FIG. It is a characteristic curve figure which shows the characteristic of the antenna in the VHF band of the receiving system 11 of FIG. 14 is a chart showing in detail the characteristics of vertical polarization in the measurement result of FIG. 14 is a chart showing in detail the characteristics of horizontal polarization in the measurement result of FIG. It is a characteristic curve figure which shows the characteristic at the time of using only a relay cable in the receiving system 11 of FIG. It is a graph which shows the characteristic of the vertical polarization in the measurement result of FIG. 16 in detail. It is a graph which shows the characteristic of the horizontal polarization in the measurement result of FIG. 16 in detail. It is a characteristic curve figure which shows the characteristic at the time of using a rod antenna. FIG. 20 is a chart showing in detail the characteristics of vertical polarization in the measurement result of FIG. 19. FIG. 20 is a chart showing in detail the characteristics of horizontal polarization in the measurement result of FIG. It is a characteristic curve figure which shows the characteristic of a UHF band at the time of using only the cable of an earphone as an antenna. 23 is a chart showing in detail the characteristics of vertical polarization in the measurement result of FIG. FIG. 23 is a chart showing in detail the characteristics of horizontal polarization in the measurement result of FIG. 22. It is a characteristic curve figure which shows the characteristic of a VHF band at the time of using only the cable of an earphone as an antenna. It is a graph which shows the characteristic of the vertical polarization in the measurement result of FIG. 25 in detail. It is a graph which shows the characteristic of the horizontal polarization in the measurement result of FIG. 25 in detail. It is a block diagram which shows the structure in the case of switching an antenna output by a switch circuit. It is a block diagram which shows the structure in the case of providing a dedicated antenna in each frequency band.

Explanation of symbols

1, 8, 11 ...... Receiving system 2, 2 A, 2 B, 14 ...... Antenna 4, 15, 41 ...... High band tuner 5, 16, 42 ...... Low band tuner 12, 47 ...... High pass filter, 13, 48: Low-pass filter, 22: Relay cable, 23: Main unit, 24: Earphone, 26, 30 ... Cable, 27, 32 ... Plug, 31, 33 ... Jack

Claims (6)

A main unit,
A relay cable for transmitting signals and / or power between the main unit and an external device;
An external antenna provided in the main unit ,
The relay cable is
A plurality of core cables including a ground cable, and a covered wire formed of a conductor connected to the ground cable on the main unit side and covering the plurality of core cables, and functions as a coaxial transmission line is a multi-core coaxial cable,
Transmitting the signal and / or power by the core cable,
The external device side end of the covered wire is an open end, and the covered wire functions as a part of the antenna in cooperation with the external antenna,
Before Symbol main unit,
A high-band tuner that receives broadcast waves of a predetermined frequency band;
A low-band tuner in which the reception frequency band is set to a low frequency with respect to the reception frequency band of the high-band tuner,
The covered wire is connected to the input end, an output signal is output to the high band tuner, the reception frequency band of the high band tuner is set as a pass band, and the reception frequency band of the low band tuner is set as a cutoff band A high-band filter,
A low band in which the covered wire is connected to an input end, an output signal is output to the low band tuner, a reception frequency band of the low band tuner is set as a pass band, and a reception frequency band of the high band tuner is set as a cutoff band And a filter on the side. The high band side filter and the low band side filter are:
The receiving apparatus according to claim 1, wherein the input impedance is set to increase as the frequency moves away from the cutoff frequency in the cutoff band. The high band side filter is
One end of a capacitor is grounded via an inductor, the covered wire is connected to the other end of the capacitor, one end of the capacitor is connected to an antenna input end of the high-band tuner,
The filter on the low band side is
The receiving device according to claim 2, wherein one end of the inductor is grounded via a capacitor, the covered wire is connected to the other end of the inductor, and one end of the inductor is connected to an antenna input end of the low-band tuner. The receiving device according to claim 1, wherein the relay cable is detachably connected to the main body device and / or the external device by a connector. The receiving device according to claim 1, wherein the external device is an earphone. The external device is an earphone;
The length of the covered wire is set to ¼ of the wavelength of the reception frequency band of the high-band tuner,
The receiving apparatus according to claim 2, wherein a length obtained by adding the length of the cable of the earphone to the length of the covered wire is set to ¼ of the wavelength of the reception frequency band of the low-band tuner.

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