`(12) Patent Application Publication (10) Pub. No.: US 2003/0118196A1
`(43) Pub. Date:
`Jun. 26, 2003
`Woolfork
`
`US 2003.0118196A1
`
`(54) WIRELESS DIGITAL AUDIOSYSTEM
`(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 Classification
`
`(51) Int. Cl." ............................... H04R 1/10; H04R 5/02
`(52) U.S. Cl. .............................................. 381/74; 381/311
`(57)
`ABSTRACT
`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
`
`filter wherein the headphone plug may be connectable to a
`headphone jack of an audio Source. The low pass filter
`output signal may be in communication with an A/D con
`verter whose output may be in communication with a digital
`low pass filter 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
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`Audio Source
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`Petitioner's Exhibit 1006
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`WIRELESS DIGITALAUDIO 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 modified 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 filter wherein the headphone plug may be connect
`able to a headphone jack of an audio Source. The low pass
`filter output signal may be in communication with an A/D
`converter whose output may be in communication with a
`digital low pass filter 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 filter 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 filter 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 filter (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
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`Petitioner's Exhibit 1006
`Page 004
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`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.
`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
`Specific 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.
`0.017. 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 filter 72 may be
`used to filter the analog audio Signal to pass a signal in the
`approximate 20 Hz to 20 kHz frequency range and filter
`other frequencies. The analog audio signal may then be
`processed by a power amplifier 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.
`0.019 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:
`a headphone plug in communication with an analog low
`pass filter and connectable to a headphone jack of an
`audio Source;
`Said low pass filter output in communication with an A/D
`converter,
`Said A/D converter in communication with a digital low
`pass filter, 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; and
`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 filter;
`Said wideband band pass filter 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 filter; and
`Said analog low pass filter output in communication with
`a power amplifier 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 filter;
`Said wideband band pass filter 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 filter; and
`Said analog low pass filter output in communication with
`a power amplifier the output of which is in communi
`cation with a headphone Speaker.
`6. The audio receiver as in claim 5 wherein said demodul
`lator is a 64 Ary demodulator.
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`Petitioner's Exhibit 1006
`Page 005
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`Jun. 26, 2003
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`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 filter and connectable to a headphone jack of an
`audio Source;
`Said low pass filter output in communication with an A/D
`converter,
`Said A/D converter in communication with a digital low
`pass filter, 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 filter;
`Said wideband band pass filter 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 filter; and
`Said analog low pass filter output in communication with
`a power amplifier the output of which is in communi
`cation with a headphone Speaker.
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`Petitioner's Exhibit 1006
`Page 006
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