JPH07298384A - Headphones - Google Patents

Abstract

PURPOSE:To improve the reception sensitivity when the cords of the headphones are and used as a receiving antenna. CONSTITUTION:A remote control operation part 23 for remotely controlling a main body equipment 4 is provided halfway to the headphone cords 21 and 22. The remote control operation part 23 includes high frequency choke elements L21-L24, and R21-R2N+1 which insulate all lead lines 21L-21G of the cord 21 between a headphone plug 24 and remote control operation part 23 from the remote control operation part 23 to sound units 2L and 2R as to high frequencies. When the headphone plug 24 is connected to the headphone jack 44 of the main body equipment 4, a broadcast wave signal received by the lead lines of the cord 21G between the headphone plug 24 and remote control operation part 23 is led out to the contact 44G of the headphone jack 44. This led-out broadcast wave signal is supplied to a receiving circuit 41 of the main body equipment 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to headphones which can be used as a receiving antenna of an FM receiver, for example.

[0002]

2. Description of the Related Art In an AM receiver, a ferrite core of an antenna tuning circuit can be used as a so-called bar antenna, so that it is not necessary to connect an external antenna to the receiver. However, in the FM receiver, since the reception frequency is high, it is difficult to use the ferrite core as an antenna.

Therefore, in a portable type FM receiver or an FM receiver built in a headphone stereo, a cord of a headphone (earphone) is used as a receiving antenna.

That is, in FIG. 5, reference numeral 1 is an FM receiver which is used alone or in a headphone stereo, and 2 is a headphone. In this example, the headphone 2 is an inner ear type, 21 is its headphone cord, 2L, 2R is a left and right acoustic unit that converts an audio signal into sound. Then, by selecting the length of the code 21, the FM wave can be received by the code 21, and the voltage distribution of the FM wave in the code 21 can be set to the pattern shown by the solid line A.
The FM broadcast can be properly received.

[0005]

However, when actually listening to music or the like through the headphones 2, the chord portion 22 of the chords 21 of the headphones 2 close to the acoustic units 2L, 2R is the face of the listener. Touching or approaching the neck. Inner ear type headphones 2
In use, since the acoustic units 2L and 2R are inserted into the ear canal during use, the cord portion 22 touches or approaches the face or neck of the listener for a considerable length.

Therefore, the cord portion 22 and the acoustic units 2L and 2R are capacitively coupled to the face and neck of the listener, and as a result, the cord 21 of the headphone 2 is F.
Even if the M wave is received, the voltage distribution of the FM wave in the code 2 is lowered as shown by the broken line B in FIG. 5, and the signal level of the FM wave supplied to the receiver 1 is lowered. That is, even if the code 21 receives the FM wave, a part of the received signal is bypassed to the listener's face and neck,
The reception sensitivity of FM waves will decrease.

The present invention is intended to solve such a problem.

[0008]

Now, considering an FM receiver capable of remote control of channel selection, volume, etc., as shown in FIG. 4A, the remote control operation unit (remote control operation unit) 23 is a headphone. Code 2 of 2
And is provided in the middle of the cord 22. Further, in the headphone stereo having the FM receiver 1 built-in, the headphone stereo main body and the built-in FM receiver 1 can be remote-controlled, but the remote control operation unit 23 thereof also has the cord 21 and the cord 22 of the headphone 2. It is provided on the way.

[0009] The present invention focuses on such a point, and the appearance and operability are the same as those of the headphone 2 having the remote control operation unit 23 so far, but the reception sensitivity can be improved.

That is, in the present invention, when the reference numerals of the respective parts correspond to the embodiments described later, they are connected to the acoustic units 2L and 2R for converting the audio signals L and R into sounds and the headphone jack 44 of the main unit 4. The headphone plug 24 and the audio signals L and R supplied to the headphone plug 24 by connecting between the headphone plug 24 and the sound units 2L and 2R are connected to the sound units 2L and 2L.
The cords 21 and 22 supplied to the R, the remote control operation unit 23 provided in the middle of the cords 21 and 22 to remote control the main body device 4, and the headphone plug 24 and the remote control operation unit provided inside the remote control operation unit 23. All lead wires 21L to 21G of the cord 21 to and from 23
Is provided with high-frequency choke elements L21 to L24 and R21 to R2N + 1 which insulate the remote control operating section 23 from the acoustic units 2L and 2R in a high frequency manner. Connected to the headphone jack 44, the broadcast wave signal received by the lead wire of the cord 21G between the headphone plug 24 and the remote control operation part 23 is taken out to the contact point 44G of the headphone jack 44, and the taken out broadcast wave signal is used as a main device. 4 to the receiving circuit 41.

[0011]

The cord 21 of the headphone 2 acts as a receiving antenna that is insulated from the outside at high frequencies, and the receiving sensitivity is improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 4 is a headphone stereo having a built-in FM receiver, 41 is a reproducing circuit for reproducing a tape cassette, and 42 is a synthesizer system.
F with antenna input circuit to stereo demodulation circuit
M receiver circuits, 43L and 43R are output amplifiers, and 44 is a headphone jack.

At the time of reproducing the cassette, the reproducing circuit 41 reproduces and takes out the audio signals L and R of the left and right channels from the cassette.
R is supplied to the amplifiers 43L and 43R. Further, at the time of receiving the FM broadcast, the left and right channel audio signals L and R are extracted from the receiving circuit 42, and the signals L and R are extracted.
R is supplied to the amplifiers 43L and 43R.

Further, 45 is a microcomputer for system control, in which various operation keys 46 are provided.
Is connected and a control signal according to the operation result is supplied to the circuits 41, 42, 43L, 43R, and the circuits 41 to 43R are set to the operation mode corresponding to the operated key.

The output terminals of the amplifiers 43L and 43R are
Jack 44 through high frequency choke coils L41 and L42
And the remote control contact 44C of the jack 44 is connected to the input terminal A / D of the analog input port (built-in A / D converter) of the microcomputer 45 through the high frequency choke coil L43, and this terminal A resistor R41 for voltage division is connected to A / D.

Further, the ground contact (common contact) 44G of the jack 44 is grounded through the high frequency choke coil L44 and connected to the antenna input end of the receiving circuit 42 through the band pass filter 47 having the pass band of the frequency band of the FM wave. To be done.

In the present invention, the headphones 2 are constructed, for example, as shown in FIG. That is,
In the headphone 2, 24 is a headphone plug, and when the plug 24 is inserted into the jack 44,
It has contacts 24L, 24R, 24C and 24G connected to the contacts 44L, 44R, 44C and 44G, respectively. Then, the contact 24L of the plug 24 is connected to the left channel acoustic unit 2L through the lead wire 21L of the cord 21 → the high frequency choke coil L21 → the hot side signal line of the lead wire 22L of the left channel of the cord 22.

Further, the contact 24R of the plug 24 is connected to the right channel acoustic unit 2R through the lead wire 21R of the cord 21 → high frequency choke coil L22 → the signal line on the hot side of the right channel lead wire 22R of the cord 22. .

Further, the contact 24G of the plug 24 is the lead wire 21G of the cord 21 → high frequency choke coil L24 →
The left and right channel acoustic units 2L, 2R through the signal lines on the cold side of the lead wires 22L, 22R.
Connected to.

The contact 24C of the plug 24 is connected to the remote control operation circuit 231 through the lead wire 21C of the cord 21.
Connected to. This remote control operation circuit 231 includes resistors R21 to R21 connected in series between the lead wires 21C and 21G.
It is composed of R2N + 1 and operation switches S21 to S2N for remote control. The switches S21 to S2N are non-lock type normally open switches, and when they are turned on,
The resistors R41 and R21 to R2N + 1 are connected so that the voltage division ratio changes.

Further, in this case, the elements L21, L22, L24,
R21 to R2N + 1 and S21 to S2N are provided inside the remote controller operation unit 23 as shown by being surrounded by a chain line in FIG. Furthermore, the code 2 from the plug 24 to the remote control operation unit 23
The length of 1 is a length considering the operability when the headphone stereo 4 is stored in a bag or the like and the reception frequency band of the reception circuit 42.

For example, if the reception frequency band is 76 to 90 MHz, the center frequency is 83 MHz, which is 1/4 of that frequency.
The wavelength is about 90 cm. And the length of the cord 21 is 90 cm
In this case, even if the headphone stereo 4 is stored in a bag or the like, the operation section 23 can be sufficiently operated. Therefore, the length of the cord 21 is, for example, 90 cm.

The length of the cord 22 from the remote control operating section 23 to the acoustic units 2L, 2R may be a general length. In addition, high frequency choke coils L41 to L44, L2
The values of 1, L22 and L24 are, for example, 10 μH.

According to this structure, when the plug 24 is inserted into the jack 44, these contacts 24L to 24G are formed.
And the contacts 44L to 44G are connected to each other. At this time, a resistor R41 and resistors R21 to R2N + 1 form a voltage dividing circuit, and the divided voltage is the input terminal A / of the analog input port of the microcomputer 45.
When the switches S21 to S2N are pressed while being supplied to D, the voltage division ratio changes and the divided voltage supplied to the terminal A / D changes. Then, the change in the divided voltage is detected by the microcomputer 45, and the headphone stereo 1 is controlled to the operation mode corresponding to the pressed switch.

Then, for example, when the headphone stereo 1 is set to the reproduction mode, the amplifiers 43L and 43R output the audio signals L and R reproduced by the reproduction circuit 41. The audio signals L and R are Contact point 44
L, 44R → contact 24L, 24R → lead wire 21L, 2
1R → coil L21, L22 → lead wire 22L, 22R → acoustic unit 2L, 2R → coil L24 → lead wire 21G →
It is supplied to the acoustic units 2L and 2R through the signal line of the contact 24G → the contact 44G → the coil L44 → the ground. Therefore, the music or the like reproduced by the headphone stereo 4 can be heard by the headphone 2.

Further, in this case, of the lead wires 21L to 21G of the headphone cord 21, the lead wires 21L to 21G.
High frequency choke coils L41 to L43, L21, L22 and resistors R21 to R2N + 1 isolate C from other parts in terms of high frequency.

Therefore, the lead wire 21G acts as an antenna to receive the FM wave signal, and the received signal is supplied to the receiving circuit 42 through the signal line of the contact point 24G.fwdarw.contact point 44G.fwdarw.bandpass filter 47. FM broadcasting can be listened to through the audio signal line.

At this time, since the ends of the lead wire 21G on the side of the acoustic units 2L, 2R are insulated from the lead wires 22L, 22R at high frequencies by the high frequency choke coil L24, the lead wire 21G acts as an antenna. At this time, the voltage distribution of the FM wave in the lead wire 21G becomes as shown by the solid line C in FIG. 4B, and does not distribute from the high frequency choke coil L24 to the units 2L, 2R side. The length of the code 21 is almost 1 of the FM wave received.
Since the wavelength is set to / 4 wavelength, the position of the remote controller operation unit 23 becomes the antinode of the voltage distribution of the received FM wave.

Therefore, the lead wire 21G acts as an antenna having appropriate characteristics for FM waves.
Sufficient sensitivity can be obtained as an FM antenna.

FIG. 3 shows an example of the measurement result of the receiving sensitivity in the circuit of FIG. 2, and each numerical value is as described above. Further, the measurement results are standardized based on the reception sensitivity in the state shown in FIG.

According to this measurement result, the reception sensitivity is improved by at least about 5 dB in the frequency band of FM broadcasting of 76 to 90 MHz, and is improved by about 11 dB depending on the frequency.

Further, according to this measurement result, since resonance occurs due to the high frequency choke coils L41 to L44, L21, L22, L24 and the stray capacitance of the headphone stereo 4, a peak appears in the sensitivity characteristic of the measurement result. The high frequency choke coils L41 to L44, L21, L2
2. By changing the values of L24, the frequency position of the peak part of the characteristic curve could be changed. Therefore, it can be seen that the present invention is effective even when the broadcast wave band is different from the case of FIG.

Thus, according to the headphone 2, the reception sensitivity when the headphone cord 21 is used as the antenna of the receiver can be improved.

In the above description, the resistors R41 and R21 are used.
The microcomputer 45 detects the pressed switch among the switches S21 to S2N by changing the voltage division ratio by R2 to R2N + 1. However, the method of detecting the operated switch is arbitrary. For example, it can be detected by dynamic scanning. In that case, the high frequency choke coil L43 can be replaced by a resistor.

Further, when the remote control operation unit 23 has an LCD for displaying the operation mode, etc., the lead wire of the cord 21 and the contact of the jack 44 provided therefor are similar to the high frequency choke coils L21 and L41. A high frequency choke coil may be provided in the. That is, in any case, all the lead wires of the cord 21 are insulated from the cord 22 at a high frequency in the remote control operation part 23, and the contacts of the jack 44 are also high frequency except for the contact for taking out the received signal. Insulate to.

[0036]

According to the present invention, the reception sensitivity of the headphone 2 when the headphone cord 21 is used as an antenna of a receiver can be improved. Further, since the high frequency choke coils L21, L22, L24 are provided in the remote control operation unit 23, that is, it is not necessary to provide only the high frequency choke coils L21, L22, L24 in the middle of the headphone cord 21, so that the headphones Two
The design and usability of the remote control operation unit 23 are the same as those of the past.

Moreover, the high frequency choke coils L21 and L2
2. Only need to add 2 and L24, so the cost increase is extremely small. Furthermore, since the characteristics of the headphones 2 as an antenna are improved, as long as the plug 24 is adapted,
It is possible to improve the reception sensitivity regardless of the model of the headphone stereo or the FM receiver, or even if the model is already on the market.

[Brief description of drawings]

FIG. 1 is a connection diagram showing an example of a headphone stereo.

FIG. 2 is a connection diagram showing an example of the present invention.

FIG. 3 is a diagram showing an example of measurement results of the example of FIG.

FIG. 4 is a diagram for explaining the present invention.

FIG. 5 is a diagram for explaining characteristics of headphones as a receiving antenna.

[Explanation of symbols]

 2 stereo headphones 2L sound unit (for left channel) 2R sound unit (for right channel) 4 headphone stereo 21 code 22 code 23 remote control operation part 24 headphone plug 41 playback circuit 42 FM receiving circuit 43L output amplifier (left channel) 43R output Amplifier (for right channel) 44 Headphone jack 45 Microcomputer 46 Operation key 47 Band pass filter L21 to L24 High frequency choke coil L41 to L44 High frequency choke coil S21 to S2N Remote control switch

Claims (4)

[Claims] 1. An audio unit for converting an audio signal into a sound, a headphone plug connected to a headphone jack of a main body device, and a headphone plug connected to the headphone plug and supplied to the headphone plug. A code for supplying an audio signal to the acoustic unit, a remote control operating section provided in the middle of the code for remote controlling the main body device, and a headphone plug and the remote control operating section provided inside the remote control operating section. And a high-frequency choke element that insulates all the lead wires of the cord between the remote control operation unit and the acoustic unit side in a high frequency manner, and the headphone plug is connected to the headphone jack of the main body device. When connected, the headphone jack contacts Taking out a broadcast wave signal received in the lead of the cord between the Ddohonpuragu and the remote control unit, headphones the broadcast wave signal taken out so as to supply to the receiving circuit of the main device. 2. The headphone according to claim 1, wherein the high frequency choke element is a high frequency choke coil. 3. The headphone according to claim 1 or 2, wherein a length of the cord between the headphone plug and the remote control operation unit is set to a frequency near a center of a reception frequency band of the reception circuit. Headphones set to about 1/4 of the wavelength. 4. The headphone according to claim 1, 2, or 3, wherein the receiving circuit is an FM broadcast receiving circuit.