(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2003/0118196 A1
`(43) Pub. Date:
`Jun. 26, 2003
`Woolfork
`
`US 20030118196A1
`
`(54) WIRELESS DIGITAL AUDIO SYSTEM
`
`(76) Inventor: C. Earl Woolfork, Altadena, CA (US)
`
`Correspondence Address:
`Dennis W. Beech
`LAW OFFICES OF DENNIS W. BEECH
`Suite C-2
`19900 Beach Blvd.
`Huntington Beach, CA 92648 (US)
`
`(21) Appl. No.:
`
`10/027,391
`
`(22) Filed:
`
`Dec. 21, 2001
`
`Publication Classi?cation
`
`(51) Int. Cl.7 ............................. .. H04R 1/10; H04R 5/02
`(52) US. Cl. ............................................ .. 381/74; 381/311
`
`ABSTRACT
`(57)
`The present invention is directed to Wireless digital audio
`systems for transmission of a signal from an audio player
`device to a headphone. An audio transmitter may include a
`headphone plug in communication With an analog loW pass
`
`?lter Wherein the headphone plug may be connectable to a
`headphone jack of an audio source. The loW pass ?lter
`output signal may be in communication With an A/D con
`verter Whose output may be in communication With a digital
`loW pass ?lter that outputs a signal to an encoder. The
`encoder output may be in communication With a channel
`encoder the output of Which may be in communication With
`a block interleaver. The block interleaver output may be in
`communication With a modulator the output of Which may
`be summed With a transmitter code generator output in a
`summating element. The modulator may be a 64 Ary modu
`lator. The summating element output may be in communi
`cation With a differential phase shift key transmitter the
`output of Which may be in communication With a transmit
`antenna for Wireless transmission of a signal. The transmit
`ted signal may be transmitted to an audio receiver for
`processing to poWer a headphone speaker. It is emphasized
`that this abstract is provided to comply With the rules
`requiring an abstract that Will alloW a searcher or other
`reader to quickly ascertain the subject matter of the technical
`disclosure. It is submitted With the understanding that it Will
`not be used to interpret or limit the scope or meaning of the
`claims.
`
`Antenna
`
`/
`
`Audio Source
`
`SONY Exhibit 1004 - 0001
`
`

`

`Patent Application Publication Jun. 26, 2003 Sheet 1 of 2
`
`US 2003/0118196 A1
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`SONY Exhibit 1004 - 0002
`
`

`

`Patent Application Publication Jun. 26, 2003 Sheet 2 0f 2
`
`US 2003/0118196 A1
`
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`SONY Exhibit 1004 - 0003
`
`

`

`US 2003/0118196 A1
`
`Jun. 26, 2003
`
`WIRELESS DIGITAL AUDIO SYSTEM
`
`BACKGROUND OF THE INVENTION
`
`[0001] This invention relates to audio player devices and
`more particularly to systems that include headphone listen
`ing devices. The neW audio system uses existing audio
`player device headphone jacks to connect a transmitter for
`Wireless transmission of a signal to a receiving headphone.
`
`[0002] Use of audio headphones With audio player devices
`such as radio, tape players, CD players, computers, televi
`sion audio and the like have been in use for may years. Such
`use includes the portable player systems such as cassette
`tape players that may be used during exercising as for
`example running. These systems usually incorporate an
`audio source having a headphone jack to Which a headphone
`is connected by Wire and connector.
`
`[0003] There are also knoWn Wireless headphones that
`may receive radio transmissions. Also, audio player devices
`have been modi?ed to alloW Wireless communication With a
`headphone receiver. HoWever, these systems do not alloW
`use of a simple plug in transmitter for connection to the
`audio player device jack for Wireless transmission betWeen
`space separated devices.
`
`[0004] As can be seen, there is a need for a simple
`connection system for existing audio player devices to alloW
`Wireless transmission to a headphone receiver.
`
`SUMMARY OF THE INVENTION
`
`[0005] The present invention is directed to Wireless digital
`audio systems for transmission of a signal from an audio
`player device to a headphone. An audio transmitter may
`include a headphone plug in communication With an analog
`loW pass ?lter Wherein the headphone plug may be connect
`able to a headphone jack of an audio source. The loW pass
`?lter output signal may be in communication With an A/D
`converter Whose output may be in communication With a
`digital loW pass ?lter that outputs a signal to an encoder. The
`encoder output may be in communication With a channel
`encoder the output of Which may be in communication With
`a block interleaver. The block interleaver output may be in
`communication With a modulator the output of Which may
`be summed With a transmitter code generator output in a
`summating element. The modulator may be a 64 Ary modu
`lator. The summating element output may be in communi
`cation With a differential phase shift key transmitter the
`output of Which may be in communication With a transmit
`antenna for Wireless transmission of a signal. The transmit
`ted signal may be transmitted to an audio receiver for
`processing to poWer a headphone speaker.
`
`[0006] These and other features, aspects and advantages of
`the present invention Will become better understood With
`reference to the folloWing draWings, description and claims.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0007] FIG. 1 illustrates a schematic diagram representa
`tion of the Wireless digital audio system;
`
`[0008] FIG. 2 illustrates a functional block diagram of the
`audio transmitter according to an embodiment of the inven
`tion;
`
`[0009] FIG. 3 illustrates a functional block diagram of the
`audio receiver according to an embodiment of the invention.
`
`DETAILED DESCRIPTION
`
`[0010] The folloWing detailed description is the best cur
`rently contemplated modes for carrying out the invention.
`The description is not to be taken in a limiting sense, but is
`made merely for the purpose of illustrating the general
`principles of the invention.
`
`[0011] Referring to FIG. 1, a Wireless digital audio system
`10 may include an audio transmitter 20 connected to an
`audio player or audio source 80. The audio transmitter 20
`may be connected to the audio source 80 headphone jack 82
`using a headphone plug 22. The audio transmitter 20 may
`have a transmitting antenna 24 that may be omni-directional
`for transmitting an electromagnetic signal to a receiving
`antenna 52 of an audio receiver 50 that may be a headphone
`receiver. The audio receiver 50 may have headphone speak
`ers 54 in headphones 55 for listening to the audio signal. The
`audio system 10 may digitiZe the audio signal and may
`transmit an electromagnetic signal at 2.4 GHZ using
`approximately 100 milliWatts or less of poWer.
`
`[0012] Referring to FIG. 2, an audio transmitter 20 may
`receive an audio signal from an audio source 80. The audio
`transmitter 20 may be a compact device that may be con
`nected to the audio source 80 to remain thereWith for
`transmitting a signal to an audio receiver. An audio source
`80 normally provides an analog output signal in the approxi
`mate range of 20 HZ to 20 kHZ. This signal may then be
`processed through an analog loW pass ?lter 30 to then be
`digitiZed by a 4 bit analog-to-digital (A/D) converter 32.
`After digital conversion of the analog audio signal, the
`digital signal may be processed by a digital loW pass ?lter 34
`to reduce unWanted out of band noise that may have been
`produced by the A/D converter 32.
`
`[0013] An encoder 36 may be used to reduce intersymbol
`interference (ISI) by using a transform code to encode the
`digital signal. The reduction of ISI may loWer the probability
`of a signal detection error in the audio receiver. The digital
`signal may next be processed by a channel encoder 38 and
`a block interleaver 40 to produce encoded redundancies in
`the transmitted signal to reduce errors that may occur during
`transmission.
`
`[0014] Modulation of the digital signal may be performed
`using direct sequence spread spectrum communication tech
`nology. A 64-Ary modulator 42 may be used for summation
`at summation element 46 With a transmitter code generator
`44 signal to produce a high symbol rate, and a unique
`codeWord that spreads the signal spectrum. The output of the
`summation element 46 may then be communicated to a
`differential phase shift key (DPSK) transmitter 48 that
`modulates the digital signal to be transmitted by an omni
`directional transmitting antenna 24 at approximately 2.4
`GHZ. The transmit poWer may be limited to 100 milliWatts.
`
`[0015] The transmitted signal from transmit antenna 24
`may be received by receiving antenna 52 and communicated
`to a Wideband band pass ?lter (BPF) 54. The received spread
`spectrum signal may then be communicated to a 2.4 GHZ
`direct conversion receiver 56. The direct conversion receiver
`56 may provide a method for doWn converting the received
`signal While utiliZing timing and synchroniZation to capture
`
`SONY Exhibit 1004 - 0004
`
`

`

`US 2003/0118196 Al
`
`Jun. 26, 2003
`
`the correct bit sequence embedded in the received spread
`spectrum signal. The audio receiver 50 may utilize fuZZy
`logic (or continuous logic) to optimiZe performance of the
`audio receiver 50.
`
`said block interleaver output in communication With a
`modulator the output of Which is summed With a
`transmitter code generator output in a summing ele
`ment; and
`
`[0016] The doWn converted output signal of the direct
`conversion receiver 56 may be summed in receiver summing
`element 58 With a receiver code generator 60 signal. The
`receiver code generator 60 may contain the same unique
`code Word that Was transmitted by the audio transmitter 20
`speci?c to a particular a user. Other code Words from
`Wireless digital audio systems 10 may appear as noise to a
`particular audio receiver 50. This may also be true for other
`device transmitted signals operating in the Wireless digital
`audio system 10 spectrum. This code division multiple
`access (CDMA) may be used to provide each user indepen
`dent operation.
`[0017] The resulting summed digital signal from receiving
`summary element 58 may be processed by a 64-Ary
`demodulator 62 to demodulate the signal elements modu
`lated in the audio transmitter 20. A block de-interleaver 64
`may then decode the bits of the digital signal encoded in the
`block interleaver 40. FolloWing such, a Viterbi decoder 66
`may be used to decode the bits encoded by the channel
`encoder 38 in the audio transmitter 20. A source decoder 68
`may further decode the coding applied by the encoder 36.
`The resultant processed digital signal may thereby be con
`dition to represent the original signal processed and trans
`mitted by the audio transmitter 20.
`
`[0018] The neXt step may process the digital signal to
`return the signal to analog or base band format for use in
`poWering a speaker 54. A digital-to-analog converter 70
`(DAC) may be used to transform the digital signal to an
`analog audio signal. An analog loW pass ?lter 72 may be
`used to ?lter the analog audio signal to pass a signal in the
`approximate 20 HZ to 20 kHZ frequency range and ?lter
`other frequencies. The analog audio signal may then be
`processed by a poWer ampli?er 74 that may be optimiZed for
`poWering a headphone speaker 54 to optimiZe a high quality,
`loW distortion signal for hearing by a user Wearing the
`headphones 55.
`[0019] While the invention has been particularly shoWn
`and described With respect to the illustrated and preferred
`embodiments thereof, it Will be understood by those skilled
`in the art that the foregoing and other changes in form and
`details may be made therein Without departing from the
`spirit and scope of the invention.
`
`I claim:
`1. An audio transmitter for Wireless transmission of a
`signal from an audio source to a headphone comprising:
`
`said summing element output in communication With a
`differential phase shift key transmitter the output of
`Which is in communication With a transmit antenna for
`Wireless transmission of a signal.
`2. The audio transmitter as in claim 1 Wherein said signal
`is transmitted to an audio receiver of said headphone com
`prising:
`
`a receiving antenna in communication With a Wideband
`band pass ?lter;
`
`said Wideband band pass ?lter in communication With a
`direct conversion receiver the output of Which is
`summed With a receiver code generator in a receiver
`summing element;
`
`said receiver summing element in communication With a
`demodulator the output of Which is in communication
`With a block de-interleaver;
`
`said block de-interleaver output in communication With a
`Viterbi decoder the output of Which is in communica
`tion With a source decoder;
`
`said source decoder output in communication With a D/A
`converter the output of Which is in communication With
`an analog loW pass ?lter; and
`
`said analog loW pass ?lter output in communication With
`a poWer ampli?er the output of Which is in communi
`cation With a headphone speaker.
`3. The audio transmitter as in claim 1 Wherein said
`modulator is a 64-Ary modulator.
`4. The audio transmitter as in claim 2 Wherein said
`demodulator is a 64 Ary demodulator.
`5. An audio receiver for packaging in a headphone com
`prising:
`
`a receiving antenna in communication With a Wideband
`band pass ?lter;
`
`said Wideband band pass ?lter in communication With a
`direct conversion receiver the output of Which is
`summed With a receiver code generator in a receiver
`summing element;
`
`said receiver summing element in communication With a
`demodulator the output of Which is in communication
`With a block de-interleaver;
`
`a headphone plug in communication With an analog loW
`pass ?lter and connectable to a headphone jack of an
`audio source;
`
`said block de-interleaver output in communication With a
`Viterbi decoder the output of Which is in communica
`tion With a source decoder;
`
`said loW pass ?lter output in communication With an A/D
`converter;
`said A/D converter in communication With a digital loW
`pass ?lter, the output of Which is in communication
`With an encoder;
`
`said encoder output in communication With a channel
`encoder the output of Which is in communication With
`a block interleaver;
`
`said source decoder output in communication With a D/A
`converter the output of Which is in communication With
`an analog loW pass ?lter; and
`
`said analog loW pass ?lter output in communication With
`a poWer ampli?er the output of Which is in communi
`cation With a headphone speaker.
`6. The audio receiver as in claim 5 Wherein said demodu
`lator is a 64 Ary demodulator.
`
`SONY Exhibit 1004 - 0005
`
`

`

`US 2003/0118196 A1
`
`Jun. 26, 2003
`
`7. A Wireless digital audio system for Wireless transmis
`sion of a signal from an audio source to a headphone
`comprising:
`a headphone plug in communication With an analog loW
`pass ?lter and connectable to a headphone jack of an
`audio source;
`
`said loW pass ?lter output in communication With an A/D
`converter;
`said A/D converter in communication With a digital loW
`pass ?lter, the output of Which is in communication
`With an encoder;
`
`said encoder output in communication With a channel
`encoder the output of Which is in communication With
`a block interleaver;
`
`said block interleaver output in communication With a
`modulator the output of Which is summed With a
`transmitter code generator output in a summing ele
`ment;
`said summing element output in communication With a
`differential phase shift key transmitter the output of
`Which is in communication With a transmit antenna for
`Wireless transmission of a signal to a receiving antenna;
`
`said receiving antenna in communication With a Wideband
`band pass ?lter;
`
`said Wideband band pass ?lter in communication With a
`direct conversion receiver the output of Which is
`summed With a receiver code generator in a receiver
`summing element;
`
`said receiver summing element in communication With a
`demodulator the output of Which is in communication
`With a block de-interleaver;
`
`said block de-interleaver output in communication With a
`Viterbi decoder the output of Which is in communica
`tion With a source decoder;
`
`said source decoder output in communication With a D/A
`converter the output of Which is in communication With
`an analog loW pass ?lter; and
`
`said analog loW pass ?lter output in communication With
`a poWer ampli?er the output of Which is in communi
`cation With a headphone speaker.
`
`SONY Exhibit 1004 - 0006
`
`