U.S. patent number 7,181,024 [Application Number 09/705,035] was granted by the patent office on 2007-02-20 for portable audio listening apparatus.
This patent grant is currently assigned to Sony Corporation. Invention is credited to Chisato Numaoka, Haruo Oba, Shigeru Tajima, Keiichi Totsuka.
United States Patent |
7,181,024 |
Oba , et al. |
February 20, 2007 |
Portable audio listening apparatus
Abstract
A portable audio listening apparatus includes, for example, a
portable audio playback apparatus serving as a portable
transmission apparatus and a headphone serving as a portable
receiving apparatus. The portable audio playback apparatus has an
electrode at its side. The headphone includes an ear pad made from
an electrically conductive material and an electric-circuit unit.
The ear pad serves as an electrode and is connected to the
electric-circuit unit by wiring. The electric-circuit unit includes
a signal processing circuit and a battery. When the user wears the
portable audio playback apparatus and the headphone, a transmission
path is formed through the body of the user. A signal reproduced by
the portable audio playback apparatus is sent through the body of
the user and the ear pad to the electric-circuit unit of the
headphone.
Inventors: |
Oba; Haruo (Kanagawa,
JP), Totsuka; Keiichi (Tokyo, JP), Tajima;
Shigeru (Kanagawa, JP), Numaoka; Chisato
(Kanagawa, JP) |
Assignee: |
Sony Corporation (Tokyo,
JP)
|
Family
ID: |
18123551 |
Appl.
No.: |
09/705,035 |
Filed: |
November 2, 2000 |
Foreign Application Priority Data
|
|
|
|
|
Nov 11, 1999 [JP] |
|
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P11-320629 |
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Current U.S.
Class: |
381/77; 381/74;
381/79 |
Current CPC
Class: |
H04B
13/005 (20130101) |
Current International
Class: |
H04B
3/00 (20060101); H04B 5/00 (20060101) |
Field of
Search: |
;381/74,77,334,311,79
;600/547 ;345/156 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Mei; Xu
Attorney, Agent or Firm: Bell, Boyd & Lloyd LLP
Claims
What is claimed is:
1. A portable audio listening apparatus comprising: a transmission
apparatus and a portable receiving apparatus electrically and
mechanically structured as different units, the portable
transmission apparatus comprising: means for generating an audio
modulated signal modulated in a band in which a signal is
transferred by using a human body of a single user, wherein the
audio modulated signal is generated based on stored audio data; and
a first electrode for outputting the generated audio modulated
signal, and the portable receiving apparatus comprising: a second
electrode for receiving the audio modulated signal transferred
through the first electrode and then through the body of the single
user; means for demodulating the audio modulated signal received by
the second electrode and downloading said demodulated signal into
said audio listening apparatus for storage; and means for
generating audible sound according to the stored demodulated
signal; wherein said second electrode is adapted to receive the
audio module signal sent from an audio-signal transmission
apparatus, wherein the portable receiving apparatus further
comprises a transmitter for transmitting a second audio modulated
signal through the body of the single user; and wherein the
portable audio listening apparatus includes a second portable
receiving apparatus, wherein the second portable receiving
apparatus includes: a third electrode for receiving the second
audio modulated signal transferred through the body of the single
user; second means for demodulating the second audio modulated
signal received by the third electrode; and second means for
generating audible sound according to the demodulated second audio
modulated signal.
2. A portable audio listening apparatus according to claim 1,
wherein the transmission apparatus further comprises means for
storing individual authentication data.
3. A portable audio listening apparatus according to claim 1,
wherein the receiving apparatus further comprises means for storing
individual authentication data.
4. A portable audio listening apparatus according to claim 1,
wherein the portable receiving apparatus includes playback means
for playing back an audio signal to be modulated and control means
for controlling the playback means, wherein the playback means
accommodates a detachable recording medium and reproduces an audio
signal from the recording medium.
5. A portable audio listening apparatus according to claim 1,
wherein the receiving apparatus further comprises recording means
for recording an audio signal in a predetermined form, said
receiving apparatus receives, by an electrode, an audio modulated
signal transferred from a predetermined another transmission
apparatus by using a human body, and demodulates the received audio
modulated signal and records it in a predetermined recoding form by
using the recording means.
6. A portable audio listening apparatus according to claim 5,
wherein the frequency band of an audio modulated signal transmitted
by the transmission apparatus is made different from that of an
audio modulated signal transmitted by the predetermined another
transmission apparatus.
7. A portable audio listening apparatus according to claim 1,
wherein the third electrode, the second demodulating means and the
second audible sound generating means are incorporated into a
headphone.
8. A portable audio listening apparatus according to claim 1,
wherein the third electrode is at least one ear pad on the
headphone.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to portable audio listening
apparatuses, and more specifically, to a portable audio listening
apparatus in which a headphone can be connected to a player at any
place without wire.
2. Description of the Related Art
Conventionally, portable players, typical of which is a Walkman (a
trade name of Sony Corporation), have been widely used to listen to
music by connecting them to headphones. Portable players can be put
in bags or mounted on human bodies by belts. When headphones are
used, the cables thereof may restrict the movement of the user.
Recently, musical information can be sent by radio from players to
headphones with the use of infrared light. For outdoor use,
however, it is not necessarily successful to use infrared-light
communication in natural light. It can also be considered that
musical information is distributed by radio other than infrared
light. The current technologies, however, cannot assure
high-sound-quality transfer. Therefore, a technology which allows
high-sound-quality transfer by radio even outdoors has been
demanded.
Conventionally, there has been known that communication between two
independent apparatuses each having an electrode and emitting a
weak radio wave which is insufficient in strength for communicating
with each other is made possible by enhancing the radio wave
through a human body (Japanese Unexamined Patent Application
Publication No. Hei-7-170215 and U.S. Pat. No. 5,914,701). Such a
method sufficiently transfers musical information having a quality
of super audio CD (SACD).
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the
foregoing condition. Accordingly, an object of the present
invention is to provide an audio listening apparatus which does not
cause radio interference and which allows an audio signal to be
positively transferred from a player to a headphone even in natural
light without wire.
The foregoing object is achieved in one aspect of the present
invention through the provision of a portable audio listening
apparatus including means for generating an audio modulated signal
modulated in a band in which a signal is transferred by using a
human body; a first electrode for outputting the generated audio
modulated signal; a second electrode for receiving an audio
modulated signal transferred through the first electrode and a
human body; means for demodulating the audio modulated signal
received by the second electrode; and means for generating audible
sound according to the demodulated signal.
In this structure, the modulated signal output from the first
electrode is transferred to the second electrode through a human
body and the transferred signal is demodulated to provide music
without wire. Since the modulated signal is transferred through a
human body, the radio wave itself can be weak. Therefore, the radio
wave does not cause radio interference in the vicinity. Even in
natural light, music is transferred without noise.
The foregoing object is achieved in another aspect of the present
invention through the provision of a portable audio listening
apparatus including a portable transmission apparatus and a
portable receiving apparatus electrically and mechanically
structured as different units, the portable transmission apparatus
including means for generating an audio modulated signal modulated
in a band in which a signal is transferred by using a human body;
and a first electrode for outputting the generated audio modulated
signal, and the portable receiving apparatus including a second
electrode for receiving an audio modulated signal transferred
through the first electrode and a human body; means for
demodulating the audio modulated signal received by the second
electrode; and means for generating audible sound according to the
demodulated signal.
Also in this structure, the modulated signal output from the first
electrode is transferred to the second electrode through a human
body and the transferred signal is demodulated to provide music
without wire. Since the modulated signal is transferred through a
human body, the radio wave itself can be weak. Therefore, the radio
wave does not cause radio interference in the vicinity. Even in
natural light, music is transferred without noise.
The foregoing object is achieved in still another aspect of the
present invention through the provision of a portable transmission
apparatus including means for generating an audio modulated signal
modulated in a band in which a signal is transferred by using a
human body; and an electrode for outputting the generated audio
modulated signal.
The foregoing object is achieved in yet another aspect of the
present invention through the provision of a portable receiving
apparatus including an electrode for receiving an audio modulated
signal transferred through a human body; means for demodulating the
audio modulated signal received by the electrode; and means for
generating audible sound according to the demodulated signal.
The electrode of the portable transmission apparatus may be
provided for the body of the apparatus. Alternatively, the
electrode may be connected to a predetermined wire which is
disposed near the body of the user. The former is suited to a case
in which the body of the apparatus is mounted at the waist of the
user by a belt, and the latter is suited to a case in which the
apparatus is put in a bag.
As described above, according the present invention, a wireless,
portable audio listening system which does not receive noise even
in natural light, which does not cause radio-wave disturbance to
other systems, and which does not cause radio interference is
provided.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view showing a whole system according to a first
embodiment of the present invention.
FIG. 2 is a block diagram showing the circuit structure of a
portable audio playback apparatus of the first embodiment.
FIG. 3 is a block diagram showing the structure of a signal
processing circuit of a headphone in the first embodiment.
FIG. 4 is a view showing individual authentication in the first
embodiment.
FIG. 5 is a view showing a system according to a second embodiment
of the present invention.
FIG. 6 is a block diagram showing the structure of a signal
processing circuit of a headphone in the second embodiment.
FIG. 7 is a view showing a system according to a third embodiment
of the present invention.
FIG. 8 is a block diagram showing the circuit structure of a
portable audio recording and playback apparatus in the third
embodiment.
FIG. 9 is a view showing individual authentication in the third
embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the present invention will be described below.
First Embodiment
A first embodiment of the present invention will be described
first. In this embodiment, a headphone and a portable audio
playback apparatus are used to send a reproduced audio signal to
the headphone with the body of the user being used as a
transmission path.
FIG. 1 shows a headphone 10 and a portable audio playback apparatus
20 in the first embodiment. In the figure, the headphone 10 is
formed of a headphone body 11, an electric-circuit unit 12, and ear
pads 13. The headphone 10 has the same structure as usual
headphones. The ear pads 13 provided for the headphone body 11 are
made from an electrically conductive material. The ear pads 13
serve as electrodes and are connected to the electric-circuit unit
12 by wiring (not shown). By this wiring, a signal transferred
through the body of the user and the ear pads 13 is sent to the
electric-circuit unit 12. The electric-circuit unit 12 accommodates
a signal processing circuit 14 (FIG. 3) and a battery (not
shown).
The portable audio playback apparatus 20 is almost the same as a
usual portable audio playback apparatus, such as a Walkman (trade
name) of Sony Corporation, and has an electrode 21 at its side.
When the user 100 wears the headphone 10 and the portable audio
playback apparatus 20, a transmission path is formed as indicated
by a one-dot chain line, and an reproduced output is transferred
from the portable audio playback apparatus 20 to the headphone 10.
Details of the mechanism of signal transfer through a human body
are disclosed in Japanese Unexamined Patent Application Publication
No. Hei-7-170215.
FIG. 2 shows the circuit structure of the portable audio playback
apparatus 20 shown in FIG. 1. In FIG. 2, an audio-signal playback
section 30 reproduces audio signals (for R channel and for L
channel) from a cassette tape, a Mini disk, a compact disk, or a
semiconductor memory. These media which store audio signals may be
detachable, or secured. Various recording methods can be
employed.
An R-channel reproduced signal is sent to a mixer 34 through a
level adjustment circuit 31, a modulator 32, and a band-pass filter
33 for the R channel. The modulator 32 performs modulation, for
example, at a modulation frequency of 2.3 MHz. An L-channel
reproduced signal is sent to the mixer 34 through a level
adjustment circuit 35, a modulator 36, and a band-pass filter 37
for the L channel. The output of the mixer 34 is amplified by an
output amplifier 38, and then sent to an output terminal 39. The
output terminal 39 is connected directly or indirectly to the
electrode 21 of the portable audio playback apparatus 20 shown in
FIG. 1.
FIG. 3 shows the signal processing circuit 14 provided for the
electric-circuit unit 12 shown in FIG. 1. In this figure, an input
terminal 50 is directly or indirectly connected to the electrically
conductive ear pads 13 shown in FIG. 1. A signal output from the
portable audio playback apparatus 20 is sent to the ear pads 13
through the body of the user, and then is sent from the ear pads 13
to the signal processing circuit 14 of the electric-circuit unit 12
through predetermined signal lines (not shown). The modulated
signal input to the input terminal 50 is amplified by a
preamplifier 51, and then is sent to an R-channel demodulator 52
and to an L-channel demodulator 53 and demodulated. The demodulated
audio signals are amplified by output amplifiers 54 and 55, and
then sent to speaker elements 56 and 57. The speaker elements 56
and 57 are disposed at the ear pads 13, and connected to the
electric-circuit unit 12 through predetermined wiring.
In the present embodiment, an audio signal reproduced from the
portable audio playback apparatus 20 is modulated, transferred
through a human body, which serves as a transmission path,
demodulated by the signal processing circuit 14 in the headphone
10, and output from the speaker elements 56 and 57. With this
structure, an audio signal is positively listened to without noise
even in natural light while the body of the user does not serve as
an obstacle.
The electrode 21 of the portable audio playback apparatus 20
assures a sufficient transfer characteristic with the body of the
user even if it does not directly contact the skin of the user. Of
course, the transfer characteristic may be improved by using an
appropriate material of clothes. Alternatively, some measure may be
taken so that the electrode 21 contacts the skin.
It may be also allowed that the portable audio playback apparatus
20 is connected to a wire and the wire itself or an electrode
connected to the open end of the wire contacts the body of the user
directly or through clothes. In this case, the portable audio
playback apparatus 20 may be slightly apart from the body of the
user, such as in a case in which the apparatus 20 is put in a
bag.
In the above embodiment, the ear pads 13 of the headphone 10 serve
as electrodes. The electric-circuit unit 12 may be connected to a
wire which is directly or indirectly connected to the body of the
user. The ear pads may be provided with electrodes.
As shown in FIG. 4, it is also possible that the electric-circuit
unit 12 of the headphones 10 is provided with an
authentication-data storage section 58 for storing individual
authentication data, and by using it, individual authentication is
executed by an authentication section 40 in the portable audio
playback apparatus 20. An individual-authentication method may be a
method using a simple code number or a method of authenticating a
one-time password by a challenge and response. Only when a
successful authentication is obtained, the authentication section
40 activates a playback control section 41 to output an audio
signal. It is further possible that the portable audio playback
apparatus 20 stores individual authentication data and the
headphone 10 is provided with an authentication section. In this
case, the headphone 10 is provided with a mute circuit such that
listening is allowed only when a successful authentication is
obtained.
Instead of the headphone 10, a small earphone may be used. In this
case, if the circuit section cannot be placed in the earphone, the
circuit section may be formed separately from the ear phone and
connected thereto by wire.
Second Embodiment
A second embodiment of the present invention will be described
below. In this embodiment, independent headphones 10R and 10L, one
for the right ear and the other for the left ear, are provided. A
portable audio playback apparatus 20 has the same structure as that
of the first embodiment.
FIG. 5 shows the headphones 10R and 10L of the present embodiment.
Each headphone is formed of a headphone body 11, an
electric-circuit unit 12, and an ear pad 13. The ear pad 13 is
provided with an ear support 15. The headphone 10R is for the R
channel, and the headphone 10L is for the L channel. A built-in
demodulator 62 (shown in FIG. 6) determines the channel (either the
R channel or the L channel). The headphones may be structured such
that they can be used for both R and L channels and predetermined
change-over switches determine the channels.
FIG. 6 shows the structure of a signal processing circuit 60 of the
electric-circuit unit 12 according to the present embodiment. The
signal processing circuit 60 is formed of an input terminal 50, a
preamplifier 61, a modulator 62, an amplifier 63, and a speaker
element 64. This circuit operates in the same way as shown in FIG.
3 except that the circuit performs signal processing for either of
the two channels.
Also in this structure, the user always receives a signal output
from the portable audio playback apparatus 20 by radio to listen to
sound in the same way as described in the first embodiment.
In the present embodiment, two headphones are separately prepared
for the right ear and for the left ear. Only one of the two
headphones may be used. In this case, a change-over switch may be
provided such that one of an R-channel signal, an L-channel signal,
and a mixed signal for the R and L channels can be received. To
reproduce the mixed signal, a mixer is required. If the original
signal is not a stereo signal, the circuit shown in FIG. 6 can be
used as is.
Third Embodiment
A third embodiment of the present invention will be described next.
In the present embodiment, musical data can be externally
downloaded through the body of the user. A recording function is
added to a portable audio playback apparatus 20 in the present
embodiment. Hereinafter, the apparatus is called a portable audio
recording and playback apparatus 20 for convenience.
FIG. 7 shows the present embodiment as a whole. In FIG. 7, the user
wears a headphone 10 and the portable audio recording and playback
apparatus 20. The user touches an electrode 201 provided for an
external audio-signal transmission apparatus 200 by a hand so that
an audio signal sent from the audio-signal transmission apparatus
200 is recorded by the portable audio recording and playback
apparatus 20.
According to the description of Japanese Unexamined Patent
Application Publication No. Hei-7-170215, modulation frequencies of
2.3 MHz and 2.8 MHz can be used for audio signals, and video
modulation frequencies of 11.5 to 13.5 MHz can also be used. In the
present embodiment, this frequency band is used for audio-signal
recording. For example, an audio signal to be recorded is modulated
by using a modulation frequency of 11.5 MHz and the signal is
transferred to the portable audio recording and playback apparatus
20 through the electrode and the body of the user.
FIG. 8 shows a signal processing circuit provided for the portable
audio recording and playback apparatus shown in FIG. 7. The same
symbols as those used in FIG. 2 are assigned to the portions
corresponding to those shown in FIG. 8. In FIG. 8, an electrode 39
(corresponding to the electrode 21 shown in FIG. 1) is used for
receiving a signal sent from the audio-signal transmission
apparatus 200. A signal input through the electrode 39 is sent to a
demodulator 72 through a band-pass filter 71 and demodulated. The
band-pass filter 71 passes only signals having frequencies in the
vicinity of 11 MHz. The audio-signal transmission apparatus 200
transmits, for example, converted digital signals (may transmit
analog signals although they have noise). The input signal is
waveform-shaped by a comparator 73 and sent to an audio-signal
processing circuit 74. The audio-signal processing circuit 74
restores the audio data (original data) or the original analog
audio signal according to the received signal. The musical data is
sent to an audio-signal playback section 30 and recorded. The
Moving Picture Coding Experts Group layer 3 (MPEG layer 3, or MP3)
method can be used as a recording method.
In the present embodiment, since data is transferred through a
frequency band exceeding 10 MHz, a transmission rate of about 1
Mbps can be easily achieved. Music of three minutes is transferred
within several seconds if the music is recorded by the MP3
method.
FIG. 8 shows a case in which a signal to be downloaded, including a
header signal, is transferred in one direction. An instruction to
the audio-signal transmission apparatus 200 is given by a method
other than the human-body transfer method, such as pressing a music
selection button. When a modulator circuit for a video-signal band
is added to the circuit shown in FIG. 8, bi-directional transfer
(half duplex) can be easily implemented.
As shown in FIG. 9, it is possible that an
individual-authentication-data storage section 58 is provided for
the headphone 10 or the portable audio recording and playback
apparatus 20, and an authentication section 202 provided for the
audio-signal transmission apparatus 200 executes individual
authentication. Only when a successful authentication is obtained,
a download control section 203 is activated to execute
downloading.
The present invention is not limited to the embodiments described
above, and various modifications thereof are possible. For example,
in the above embodiments, the 2.3-MHz frequency band and the
2.8-MHz frequency band are used for the R channel transfer and the
L channel transfer, respectively. Since a frequency band of 2 to 30
MHz can be used for the human-body transfer method, when the band
is divided, audio signals can be transferred through a vast number
of channels. In this case, the 5+1 channel method of Dolby Digital
(trade name) is implemented by a wireless headphone.
Conventionally, it is very difficult for wireless radio transfer to
implement such a method.
* * * * *