JP3938118B2 - Earphone antenna and portable radio equipped with the earphone antenna - Google Patents

Description

  The present invention relates to an earphone antenna of a portable radio device used by being attached to a human body, and a portable radio device equipped with the earphone antenna.

  Conventionally, in a portable radio such as a pager, a radio receiver, and a liquid crystal television receiver that are attached to a human body, there is an earphone antenna that uses a signal line for transmitting an audio signal to a rod antenna or an earphone as an antenna. in use.

JP 2003-163529 A

  By the way, in a portable radio device using a rod antenna or an earphone antenna, there is a problem that when the antenna is attached to a human body, the antenna performance is significantly deteriorated due to the attachment to the human body, and sufficient reception sensitivity cannot be obtained. there were.

  In particular, an earphone antenna that uses a signal line for transmitting an audio signal to the earphone as an antenna directly touches the human body with the earphone or the signal line, so that the human body greatly affects the radio through the antenna and greatly deteriorates the stability of reception. There was a problem.

  Further, for example, in television broadcasting in Japan, a VHF band of 90 to 108 MHz (1 to 3 ch), 170 to 222 MHz (4 to 12 ch) and a UHF band of 470 to 770 MHz (13 to 62 ch) are used. It is necessary for a liquid crystal television receiver that receives John broadcasting to receive a very wide-band high-frequency signal of 90 to 770 MHz, and the performance of conventional rod antennas and earphone antennas is inferior to that of fixed antennas. It was extremely difficult to ensure sufficient sensitivity in the frequency range.

  Accordingly, an object of the present invention is to provide a portable radio device that reduces the influence of the human body, provides a wideband and high gain earphone antenna, and ensures the stability of reception in view of the conventional problems as described above. There is to do.

The earphone antenna according to the present invention includes an earphone cable composed of two signal lines for supplying an audio signal to the earphone, and a coaxial line formed by covering a center conductor for passing a high-frequency signal with an insulator and further covering with a shield wire. and a coaxial cable signal line and one end consists of a ground line for insulating coating audio signal is connected to the radio device body via the multipolar jack, for connecting the other end of the coaxial cable to the earphone cable And connecting the central conductor of the coaxial cable directly to one signal line of the earphone cable and high impedance in the frequency band of the audio signal to the other signal line of the earphone cable. the frequency band of the high frequency signal is connected by capacitive coupling becomes low impedance, of the coaxial cable audio signal The signal line and the ground line are connected to the two signal lines of the earphone cable via a high-frequency choke coil having a low impedance in the frequency band of the audio signal and a high impedance in the frequency band of the high-frequency signal, and the coaxial cable. a signal line for audio signals directly connected to the shield wire the ground line as well as connected by capacitive coupling becomes low impedance in a frequency band of the high-frequency signal at high impedance in the frequency band of the audio signals to the shielded cable Thus, a sleeve antenna is constituted by the earphone cable and the coaxial cable.

In addition, a portable radio device according to the present invention includes a radio device body including a multi-pole jack connected to a tuner and an audio signal output unit, an earphone cable including two signal lines for supplying an audio signal to the earphone, The center conductor through which high-frequency signals are passed is covered with an insulator, and further consists of a coaxial wire covered with a shielded wire, a signal wire for sound signal insulation and a ground wire , and one end is wireless via a multi-pole jack. A coaxial cable connected to the machine main body, and a connection block for connecting the other end of the coaxial cable to the earphone cable, wherein the central conductor of the coaxial cable is one signal of the earphone cable. Connect directly to the wire and connect to the other signal line of the earphone cable with high impedance in the frequency band of audio signal and in the frequency band of high frequency signal Bonded via a low-impedance capacitive coupling, through the high-frequency choke coil which is a high impedance signal lines and ground lines for the audio signals of the coaxial cable in the frequency band of the high-frequency signal in a low impedance in the frequency band of the respective audio signals as well as connected to two signal lines of the earphone cable Te, it becomes a low impedance to signal lines for audio signals of the coaxial cable in the frequency band of the high-frequency signal at high impedance in the frequency band of the audio signal to the shield line capacitance as well as connected by bond will be the ground wire is connected directly to the shield wire consists of a earphone antenna connected via a multipolar plug and jack in the radio device body, the earphone antenna and the earphone cable A sleeve antenna is constructed with the above coaxial cable. Characterized in that it was.

The earphone antenna according to the present invention is formed by covering an earphone cable including two signal lines for supplying an audio signal to the earphone and a center conductor for passing a high-frequency signal with an insulator, and further covering with a shield wire. A coaxial cable and a connection block for connecting the other end of the coaxial cable to the earphone cable, wherein the central conductor of the coaxial cable is directly connected to one signal line of the earphone cable in the connection block; The other signal line of the earphone cable is connected to the other signal line of the earphone cable by capacitive coupling, which has high impedance in the frequency band of the audio signal and low impedance in the frequency band of the high frequency signal. In the frequency band of audio signals, the frequency of high-frequency signals is low impedance. Pass constituted by connecting through a high-frequency choke coil which is a high impedance is characterized by being configured the sleeve antenna and the earphone cable and the coaxial cable.

Furthermore, the portable radio device according to the present invention includes a radio device body including a tuner and a jack connected to an audio signal output unit, an earphone cable including two signal lines for supplying audio signals to the earphone, and a high-frequency signal. A coaxial cable formed by covering a central conductor passing through with an insulator, and further covered with a shield wire, and a connection block for connecting the other end of the coaxial cable to the earphone cable, in the connection block, A capacitive coupling in which the central conductor of the coaxial cable is directly connected to one signal line of the earphone cable, and the other signal line of the earphone cable has high impedance in the frequency band of the audio signal and low impedance in the frequency band of the high frequency signal. connect with the other signal lines of the earphone cable shield wire of the coaxial cable It is connected via a high-frequency choke coil that has low impedance in the frequency band of audio signals and high impedance in the frequency band of high-frequency signals. The earphone antenna comprises a sleeve antenna composed of the earphone cable and the coaxial cable.

In the earphone antenna according to the present invention, in the connection block, the central conductor of the coaxial cable is directly connected to one signal line of the earphone cable, and the other signal line of the earphone cable has a high impedance and high frequency signal in the frequency band of the audio signal. Are connected by capacitive coupling that has low impedance in the frequency band, and the signal line and ground line for the audio signal of the coaxial cable are low impedance in the frequency band of the audio signal and high impedance in the frequency band of the high frequency signal. Connect to the two signal lines of the earphone cable via the choke coil , and connect the signal line for the audio signal of the coaxial cable to the shielded line with high impedance in the frequency band of the audio signal and low in the frequency band of the high frequency signal. Capacitance for impedance Since the ground line as well as connected by synthesis directly connected to the shield line, the frequency band of the audio signal, the audio in a state in which the two signal lines of the earphone cable is separated into a ground line and signal line It functions as a signal transmission line, and in the frequency band of high-frequency signals, the two signal lines of the earphone cable are integrated into an antenna element, and the earphone cable and the coaxial cable function as a sleeve antenna. And a high gain can be obtained over a wide band.

In the portable radio device according to the present invention, the earphone cable composed of two signal lines for supplying audio signals to the earphone and the central conductor through which the high-frequency signal passes are covered with an insulator, and further covered with a shield wire. a coaxial cable end consists coaxial line and the signal line and the ground line for insulating coating audio signal is connected to the radio device body via a multipolar jack comprising Te, the coaxial cable and the other end of the earphone cable A connection block for connecting to the signal line, wherein the central conductor of the coaxial cable is directly connected to one signal line of the earphone cable and the other signal line of the earphone cable is connected to the frequency band of the audio signal in the connection block. in connected by capacitive coupling becomes low impedance in a frequency band of the high-frequency signal at high impedance, voice of the coaxial cable Via a high frequency choke coil comprising a high impedance signal lines and ground lines for the issue in a frequency band of the high-frequency signal in a low impedance in the frequency band of the respective audio signals as well as connected to the two signal lines of the earphone cable, the Connect the signal line for the audio signal of the coaxial cable to the shielded line by capacitive coupling that is high impedance in the frequency band of the audio signal and low impedance in the frequency band of the high frequency signal, and directly connects the ground line to the shielded line. As a result, the earphone antenna that forms the sleeve antenna with the earphone cable and the coaxial cable is connected to the radio main unit via a multi-pole plug / jack to ensure the reception stability over a wide band. can do.

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

  The present invention is applied to, for example, a liquid crystal television receiver 100 configured as shown in FIG.

  In the liquid crystal television receiver 100 shown in FIG. 1, the earphone antenna 10 according to the present invention is connected to the receiver main body 120 via a pin jack connector 110.

  As shown in FIG. 2, the pin jack connector 110 is connected to five types of lines: an antenna (Ant), a ground (Gnd), an audio L channel (L), an audio R channel (R), and a ground (Gnd). Each consists of a five-pole pin 110A and a jack 110B.

  As shown in FIG. 3, the receiver main body 120 includes a tuner unit 121, an intermediate frequency signal processing unit 122 connected to the tuner unit 121, a video signal processing unit 123 connected to the intermediate frequency signal processing unit 122, and The pin jack connector 110 includes an audio signal processing unit 124, a liquid crystal display unit 125 connected to the video signal processing unit 123, stereo speakers 126L and 126R to which stereo audio signals are supplied from the audio signal processing unit 124. A jack 110B is provided.

  In the liquid crystal television receiver 100, the jack 110B includes five movable terminals 1, 2, 5, 6, 7 and two fixed terminals 3, 4 as shown in FIG. Thus, the movable terminal 7 and the movable terminal 1 are connected to the tuner unit 121 as an antenna terminal (Ant) and a ground terminal (Gnd), and the movable terminals 2, 5 and 6 are connected to the audio L channel terminal (L), Audio R channel terminals (R) and ground terminals (Gnd) are connected to the audio signal processing unit 124, and the stereo speakers 126 </ b> L and 126 </ b> R are connected to the fixed terminals 3 and 4. The movable terminals 2 and 5 and the fixed terminals 3 and 4 constitute a normally closed switch that is opened when the pin 110A is inserted into the jack 110B, and the pin 110A is not inserted into the jack 110B. Then, the stereo audio signal output from the audio signal processing unit 124 is supplied to the stereo speakers 126L and 126R via the fixed terminals 3 and 4.

  The earphone antenna 10 has a coaxial cable 20 having one end connected to the receiver main body 120 via the 5-pole pin jack connector 110, a connection block 30 connected to the other end of the coaxial cable 20, and the connection block. 30 includes stereo earphones 40L and 40R connected to each other via two earphone cables 41 and 42.

  As shown in FIG. 4, the coaxial cable 20 has a central conductor 21 through which a high-frequency signal passes as a core wire, the central conductor 21 is covered with an insulator 22, and is further covered with a shield wire 23. Three audio signal signal lines 24L and 24R and a ground line 24C, each of which is covered with an insulation coating, are wound. The coaxial cable 20 is provided with a five-pole pin 110A connected to the center conductor 21, shield wire 23, audio signal signal lines 24L and 24R, and ground line 24C on one end side. On the other end side of the coaxial cable 20, a connection block 30 connected to the center conductor 21, shield wire 23, audio signal signal lines 24L and 24R, and ground line 24C is provided.

  As shown in FIG. 5, the connection block 30 includes a ground pattern 31 provided at the center, stereo audio signal transmission line patterns 32L and 32R provided on both sides of the ground pattern 31, and the tip of the ground pattern 31. The substrate 34 is provided with three connection lands 33L, 33R, and 33C provided on the side. The board 34 has a high-frequency choke for connecting the front end portions of the stereo audio signal transmission line patterns 32L and 32R to the first and second connection lands 33L and 33R of the three connection lands 33L, 33R and 33C. 35L, 35R, the high frequency choke 35C for connecting the ground pattern 31 to the third connection land 33C among the three connection lands 33L, 33R, 33C, the transmission line patterns 32L, 32R for the stereo audio signal, and the ground pattern 31 Are connected to the chip capacitors 36L and 36R, the chip capacitor 37L is connected to the first connection land 33L and the third connection land 33C, and the second connection land 33R is connected to the third connection land 33C. A chip capacitor 37R is mounted.

  In the connection block 30, a left earphone cable 41 including two signal lines 41A and 41B for supplying a left audio signal to the left earphone 40L is connected to the first connection land 33L and the third connection land 33C. Further, a right earphone cable 42 including two signal lines 42A and 42B for supplying a right audio signal to the right earphone 40R is connected to the second connection land 33R and the third connection land 33C.

  The coaxial cable 20 is connected to the connection block 30 as follows.

  That is, the left audio signal line 24L and the right audio signal line 24R of the coaxial cable 20 are connected to the audio signal transmission line pattern 32L formed on the substrate 34, and the ground line 24C is connected to the ground pattern 31. ing. Further, a center conductor 21 and a shield wire 23 that form the coaxial structure of the coaxial cable 20 are placed on the ground pattern 31, and the shield wire 23 is connected to the ground pattern 31. Is connected to the third connection land 33C.

  In this embodiment, as the high-frequency chokes 35L, 35R, and 35C, ferrite beads, for example, BLM18HD102SN1 size 1608 manufactured by Murata Manufacturing are used. The high frequency chokes 35L, 35R, and 35C using the ferrite beads have a low impedance for an audio signal in a frequency band of 20 kHz or less and a high impedance for a high frequency signal to prevent the passage of the high frequency signal. . The chip capacitors 36L, 36R, 37L, and 37R each have a capacity of 10 pF, and have high impedance for an audio signal in a frequency band of 20 kHz or less, thereby preventing the passage of the audio signal. It becomes low impedance for high frequency signals.

  As shown in FIG. 6, the earphone antenna 10 has two signal lines 41 </ b> A and 41 </ b> B for transmitting the audio signal to the stereo earphone speakers 40 </ b> L and 40 </ b> R on each of the left and right sides and the GND side, respectively. Earphone cables 41 and 42 made of 42A and 42B are drawn out, and in order to separate the audio signal and the high frequency signal, ferrite is provided at the input portion of the audio signal and the portion falling to the ground, that is, the connecting lands 33L, 33R and 33C. High frequency long chokes 35L, 35R, and 35C using beads are provided so that high impedance (1 kΩ or more) is used in the frequency band used for television broadcasting and low impedance is used in the audio frequency band (20 kHz or less). The audio signal and the high frequency signal are separated.

  Also, each earphone cable 41, 42 comprising two signal lines is connected to the central conductor 21 that forms the coaxial structure of the coaxial cable 20 in terms of high-frequency signal, so that it is separated in the voice region. In order to make sure that the first and second connection lands 33L and 33R and the third connection land 33C are connected by 10 pF chip capacitors 37L and 37R, respectively, the earphone cable 41 is connected in the audio region. The two signal lines 41A and 41B constituting the two and the two signal lines 42A and 42B constituting the earphone cable 42 are separated from each other, and the earphone cable 41 is connected in a high frequency signal (frequency range of the TV band). Two signal lines 41A and 41B constituting the two signal lines 42A and 42B constituting the earphone cable 42 Each was set to be one of the antenna line.

  Here, the frequency bands used for television in Japan are VHF, 90 M to 108 MHz (1 to 3 cH), 170 M to 222 MHz (4 to 12 cH), and 470 M to 770 MHz (13 to 62 cH) in the UHF band.

  Therefore, the earphone antenna 10 has a sleeve antenna structure that resonates between the coaxial cable shield wire 23 and the earphone cables 41 and 42 connected to the central conductor 21 and is long enough to receive 100 MHz in the VHF band. It was set.

  In the earphone antenna 10 in this embodiment, the coaxial cable 20 has a coaxial structure with a characteristic impedance of 75Ω, the length is 700 mm, the length of the earphone cables 41 and 42 is 40 cm, and resonates at 100 MHz. Adjusted. 200 MHz has a structure that can be received as a 1λ antenna, and UHF uses harmonic excitation (third harmonic, fifth harmonic, and seventh harmonic) of 100 MHz and 200 MHz.

  Each signal line for the audio signal of the coaxial cable 20 is connected to the ground pattern 31 via the 10 pF capacitors 36L and 36R in the connection block 30 and is connected to the shield line 23 of the coaxial cable 20. In the signal area, all functions as ground.

  The earphone antenna 10 having such a structure is mounted on a pseudo human body, the directivity of horizontal polarization is measured in an anechoic chamber, and the result of comparison with a conventional earphone tena is shown in FIGS. As is apparent from the comparison results of the reception sensitivity shown in FIG. 7, the reception sensitivity of the earphone antenna 10 is greatly improved as compared with the conventional earphone antenna in all frequency bands.

  Here, in the earphone antenna 10 shown in FIGS. 5 and 6, the lengths of the two earphone cables 41 and 42 are equal, but from the connection lands 33L, 33R, and 33C of the connection block 30 to the earphones 40L and 40R. By changing the lengths of the two earphone cables 41 and 42, it is possible to cope with different frequencies.

  Further, like the earphone antenna 10A shown in FIG. 9, high-frequency chokes (ferrite beads) 35A and 35B are inserted into one of the two earphone cables 41 and 42, for example, in the middle of the earphone cable 41 for the left audio signal. Thus, the resonance length may be shortened by separating the high-frequency signal. In the earphone antenna 10A shown in FIG. 7, the resonance length of one earphone cable 41 is 250 mm, the resonance length of the other earphone cable 42 is 400 mm, and the coaxial cable 20 has a coaxial structure with a characteristic impedance of 75Ω. The thickness was 600 mm. In the earphone antenna 10A, the other components are the same as those of the earphone antenna 10. Therefore, the same components are denoted by the same reference numerals in FIG. 9, and detailed description thereof is omitted.

  Furthermore, in the case of a monaural earphone with one earphone cable, the earphone antenna 210 configured as shown in FIG. 10 can be obtained.

  That is, the earphone antenna 210 shown in FIG. 10 covers an earphone cable 241 including two signal lines 241A and 241B for supplying an audio signal to the earphone 240 and a center conductor 221 through which a high-frequency signal is passed, and further, A coaxial cable 220 covered with a shield wire 223 and a connection block 230 for connecting the other end of the coaxial cable 220 to the earphone cable 241 are provided.

In the connection block 230, the earphone antenna 210 directly connects the central conductor 221 of the coaxial cable 220 to one signal line 241A of the earphone cable 241 and transmits an audio signal to the other signal line 241B of the earphone cable 241. It is connected via a capacitor 237 that has a high impedance in the frequency band and blocks the passage of audio signals and has a low impedance in the frequency band of the high frequency signal, and the shield wire 223 of the coaxial cable 220 is connected to the other signal of the earphone cable 241. The line 241B is connected via a high frequency choke 235 that has a low impedance in the frequency band of the audio signal and a high impedance in the frequency band of the high frequency signal.

  The earphone antenna 210 is connected to the radio device main body 320 via a pin jack connector 310.

  On the radio device 320 side, an audio signal output line 321 is connected to a high frequency signal transmission line 322 via a high frequency choke 323 using ferrite beads, and the transmission line is connected to the jack 310B constituting the pin jack connector 310. 322 and the ground line 324 are connected.

  In the earphone antenna 210, the earphone cable 241 and the coaxial cable 220 constitute a sleeve antenna, and a pin 310A provided at one end of the coaxial cable 220 is inserted into the jack 310B on the radio device main body 320 side. As a result, the radio main unit 320 is connected.

  In this way, the inner conductor 221 of the coaxial cable 220 drawn from the portable wireless device is extended from the end of the outer conductor (shield wire) 223, and the inner conductor 221 drawn from the coaxial cable 220 and the outer conductor (shield wire) are extended. By using the earphone antenna 210 in which the audio signal is superimposed on the high frequency signal, the gain can be greatly improved regardless of the vicinity of the human body.

It is a figure which shows the structure of the liquid crystal television receiver to which this invention is applied. It is a figure which shows the structure of the pin jack connector which connects a receiver main body and an earphone antenna in the said liquid crystal television receiver. 2 is a block diagram showing a configuration of the receiver main body 120. FIG. It is a figure which shows the structure of the coaxial cable which comprises the said earphone antenna. It is a figure which shows the structure of the connection block which comprises the said earphone antenna. It is a circuit block diagram which shows the electrical structure of the said earphone antenna. It is a characteristic view which shows the measurement result of the receiving sensitivity characteristic of the said earphone antenna compared with the conventional earphone antenna. It is a characteristic view which shows the measurement result of the horizontal polarization directivity of the said earphone antenna compared with the conventional earphone antenna. It is a figure which shows the other structural example of the earphone antenna which concerns on this invention. It is a figure which shows the further another structural example of the earphone antenna which concerns on this invention.

Explanation of symbols

1, 2, 5, 6, 7 Movable terminal, 3, 4 Fixed terminal, 10, 10A Earphone antenna, 20 Coaxial cable, 21 Center conductor, 22 Insulator, 23 Shield wire, 24L, 24R Signal wire, Ground wire 24C, 30 connection block, 31 ground pattern, 32L, 32R transmission line pattern, 33L, 33R, 33C connection land, 34 substrate, 35A, 35B, 35L, 35R, 35C high frequency choke, 36L, 36R, 37L, 37R chip capacitor, 40L, 40R earphone, 41, 42 earphone cable, 41A, 41B, 42A, 42B signal line, 100 LCD television receiver, 110 pin jack connector, 110A pin, 110B jack, 120 receiver body, 121 tuner section, 122 intermediate frequency signal Processing unit, 123 Video signal processing Part, 124 audio signal processing part, 125 liquid crystal display part, 126L, 126R stereo speaker, 210 earphone antenna, 220 coaxial cable, 221 center conductor, 223 shield wire, 230 connection block, 235 high frequency choke, 237 condenser, 240 earphone, 241 Earphone cable, 241A, 241B signal line, 310 pin jack connector, 310A pin, 310B jack, 320 radio unit, 321 output line, 322 transmission line, 323 high frequency choke, 324 ground line

Claims (5)

An earphone cable comprising two signal lines for supplying audio signals to the earphone;
The center conductor through which high-frequency signals are passed is covered with an insulator, and further consists of a coaxial wire covered with a shielded wire, a signal wire for sound signal insulation and a ground wire , and one end is wireless via a multi-pole jack. A coaxial cable connected to the machine body,
A connection block for connecting the other end of the coaxial cable to the earphone cable;
In the connection block, the central conductor of the coaxial cable is directly connected to one signal line of the earphone cable, and the other signal line of the earphone cable has high impedance in the frequency band of the audio signal and low in the frequency band of the high frequency signal. Connected by capacitive coupling that becomes impedance, and the signal line and the ground line for the audio signal of the coaxial cable are connected via a high-frequency choke coil that has low impedance in the frequency band of the audio signal and high impedance in the frequency band of the high-frequency signal. as well as connected to two signal lines of the earphone cable, the capacitive coupling becomes low impedance to the signal line for audio signals of the coaxial cable in the frequency band of the high-frequency signal at high impedance in the frequency band of the audio signal to the shield wire connection Then Tomo at Earphone antenna, characterized in that said ground line constituted by connecting directly to the shield wire, to constitute a sleeve antenna in the aforementioned earphone cable and the coaxial cable.   A stereo earphone connected to the connection block via two earphone cables is provided, and a high-frequency choke coil is inserted in the middle of one earphone cable so that the resonance lengths of the two earphone cables are different. The earphone antenna according to claim 1. A radio main body having a multi-pole jack connected to a tuner and an audio signal output unit;
An earphone cable comprising two signal lines for supplying audio signals to the earphone;
The center conductor through which high-frequency signals are passed is covered with an insulator, and further consists of a coaxial wire covered with a shielded wire, a signal wire for sound signal insulation and a ground wire , and one end is wireless via a multi-pole jack. A coaxial cable connected to the machine main body, and a connection block for connecting the other end of the coaxial cable to the earphone cable, wherein the central conductor of the coaxial cable is one signal of the earphone cable. Connect to the other signal line of the earphone cable with a capacitive coupling that is high impedance in the frequency band of the audio signal and low impedance in the frequency band of the high frequency signal, and is connected to the other signal line of the earphone cable. In the frequency band of the audio signal, the wire and the ground line are respectively low impedance and in the frequency band of the high frequency signal. Via a high frequency choke coil comprising a-impedance while connected to two signal lines of the earphone cable, high-frequency signal a signal line for audio signals of the coaxial cable in a high impedance in the frequency band of the audio signal to the shield wire In the frequency band, it is connected with the capacitive coupling having a low impedance, and the ground wire is directly connected to the shield wire, and the earphone antenna is connected to the radio main unit through a multi-pole plug jack. ,
A portable radio device, wherein the earphone antenna comprises a sleeve antenna composed of the earphone cable and the coaxial cable. An earphone cable comprising two signal lines for supplying audio signals to the earphone;
A coaxial cable formed by coating the center conductor through which high-frequency signals pass with an insulator, and further with a shield wire,
A connection block for connecting the other end of the coaxial cable to the earphone cable;
In the connection block, the central conductor of the coaxial cable is directly connected to one signal line of the earphone cable, and the other signal line of the earphone cable has high impedance in the frequency band of the audio signal and low in the frequency band of the high frequency signal. Connected by capacitive coupling as impedance, and the shielded cable of the coaxial cable is connected to the other signal line of the earphone cable via a high frequency choke coil that is low impedance in the frequency band of the audio signal and high impedance in the frequency band of the high frequency signal. Connected
An earphone antenna, wherein a sleeve antenna is constituted by the earphone cable and the coaxial cable. A radio main body including a jack connected to a tuner and an audio signal output unit;
An earphone cable comprising two signal lines for supplying an audio signal to the earphone, a coaxial cable in which a central conductor for passing a high-frequency signal is covered with an insulator, and further covered with a shield wire, and the other end of the coaxial cable A connection block for connecting to the earphone cable, and in the connection block, the central conductor of the coaxial cable is directly connected to one signal line of the earphone cable and audio is transmitted to the other signal line of the earphone cable. Connect with capacitive coupling that has high impedance in the signal frequency band and low impedance in the frequency band of high frequency signals, and connect the shield line of the coaxial cable to the other signal line of the earphone cable with low impedance in the frequency band of the audio signal. High frequency that is high impedance in the frequency band of the high frequency signal Be connected via the Yokukoiru consists an earphone antenna which is connected via a plug and jack in the radio device body,
A portable radio device, wherein the earphone antenna comprises a sleeve antenna composed of the earphone cable and the coaxial cable.

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