I lllll llllllll Ill lllll lllll lllll lllll lllll 111111111111111111111111111111111
`US007490037B2
`
`c12) United States Patent
`Wiese et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7 ,490,037 B2
`Feb. 10, 2009
`
`(54) METHOD AND APPARAT US FOR ENCODING
`SIGNALS
`
`(75)
`
`Inventors: Detlef Wiese, Freising (DE); J oerg
`Rimkus, Flensburg (DE)
`
`(73) Assignee: MAYAH Communications G mbH,
`Hallbergmoos (DE)
`
`( *) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 414 days.
`
`(21) Appl. No.: 11/1 43,011
`
`(22) Filed:
`
`Jw1. 2, 2005
`
`(65)
`
`Prior Publication Data
`US 2005/0240415Al
`
`Oct. 27, 2005
`
`Related U.S. Application Data
`
`(63)
`
`Continuation of application No. 09/462,049, filed on
`Apr. 3, 2000, now abandoned.
`
`(51)
`
`(52)
`(58)
`
`lnt. Cl.
`GJOL 19100
`(2006.0l)
`U.S. CJ.
`.... ........ ...... ...... 704/230; 704/ 50 I; 704/504
`Field of Classification Search .............. 704/200. 1,
`704/228, 500, 501, 502, 503, 504, 229, 230,
`704/201; 700/94; 369/59.12, 275.3
`See application file for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`5,333,155 A * 7/ 1994 Darnbacher ................. 375/240
`5,509,017 A * 4/1996 Bralldenburget al. ....... 370/477
`5,621.660 A * 4/1997 Cbaddha et aJ . ............. 7091247
`6,138,05 1 A * 10/2000 Dieterich ..................... 700/94
`FOREIGN PATENT DOCUMENTS
`
`EP
`327 IOI A2 " 8/1989
`417739 A2 * 3/ 1991
`EP
`GB
`2225516
`5/ 1990
`* cited by examiner
`Primary Examiner-Huyen X . Vo
`(74) Allorney, Agent, or Firm- Reed Smith LLP
`
`(57)
`
`ABSTR.\CT
`
`The invention concerns a method of encoding signals, in
`particular digitized audio signals, with an encoding device for
`encoding the signal in an encoding fonuat and a processing
`device for processing the encoded signal .
`
`Methods ofthac kind are known for example from European
`patent specification No 290 581 . In that case, in the bit rate(cid:173)
`reducing encoding of audio signals which are al ready present
`in digitized fom1, for example 48 kHz sampling frequency/
`16-bit resolution, psycho-acoustic phenomena of the percep(cid:173)
`tion of audio signals are used in such a way that the original bit
`rate of the audio signals is considerably reduced. Such meth(cid:173)
`ods are also familiar and standardised under the heading of
`'source encoding' (ISO 11 172 and 11318).
`
`The object of the invention is to provide a method of the kind
`set forth in the opening part of this specification. which
`resolves the above-indicated problems and in which re-cod(cid:173)
`ing operations, once encoding has been effected. are very
`substantially avoided.
`
`211990 Crouse et al. .... .... ....... 704/229
`4 ,899,384 A "
`5,199,078 A * 3/ 1993 Orglmeister .............. .. 704/230
`
`32 Claims, 5 Drawing Sheets
`
`IPR2016-01710
`UNIFIED EX1001
`
`

`
`U.S. Patent
`
`Feb. 10,2009
`
`Sheet 1of5
`
`US 7,490,037 B2
`
`-::J
`. , ,
`. ,
`N
`,
`::J
`, ,
`.
`.--
`. . .
`,
`.--
`,
`... .. -
`I
`...
`... . . . .
`.-9
`-
`. . .
`--
`.
`. --- . -
`.
`. · : ,
`-
`. .
`--
`-
`.
`.
`-
`_...,, ........ .
`-
`. . ~
`. . ,
`.
`0
`N
`(/)
`
`,
`
`'
`
`-
`
`....... ~
`
`--
`
`'
`
`I
`I
`
`.Q
`N
`(/)
`
`K- SP
`
`\,II
`
`\,II
`
`w
`~
`
`-
`-
`
`u
`
`N
`w
`u.J
`~
`
`~
`
`1
`
`~
`
`N
`u
`
`.6
`
`-
`
`(/)
`
`. , .
`.
`
`. ,
`
`, ,
`,
`
`2:
`
`~
`z
`
`

`
`U.S. Patent
`
`Feb. 10, 2009
`
`Sheet 2 of 5
`
`US 7,490,037 B2
`
`~
`
`<
`t-
`
`...-
`0
`
`l
`
`"
`
`, , ,
`
`, , , ,
`0....
`(/j
`
`~ \
`' •
`\ ..
`' ..
`..
`' \
`
`..-
`:.':
`,.._.::
`
`~
`
`::>
`
`N
`
`•
`
`

`
`U.S. Patent
`
`Feb. 10, 2009
`
`Sheet 3 of 5
`
`US 7,490,037 B2
`
`3
`-
`·-
`·-
`·-
`.L -
`,
`I ~,5 17
`\
`I -;>--.,,
`1·---i1 ~~ (
`1 e
`: · 11
`13
`!
`21
`11
`·-
`..
`·--··
`:
`.
`. -
`-
`.
`33
`
`.
`
`·-
`19
`
`39
`
`5
`
`:
`
`·1
`
`;
`
`-- ,
`I
`21
`.
`22!
`I
`20
`----<Y'23 •
`··1
`-
`.
`.. ---'
`~ t
`34
`t I • .
`--·-·-------~
`!
`I ;---··· -·----··-·-1
`-
`·· -
`·· 1 ,....____~ ;
`35 u :
`:
`: I
`!···-- ·- ~ LJ
`i t.3
`L__ :·.:=.:t-==--- _I
`25
`I I
`I I
`L .. ·----- --· - -~----··--- ·-----_J
`7
`
`I
`
`.
`
`I
`
`F 1 G. 3
`
`

`
`U.S. Patent
`
`Feb. 10, 2009
`
`Sheet 4 of s
`
`US 7 ,490,037 B2
`
`Keypad ,
`
`Fl G. 4
`
`

`
`-....l = N
`'"= = w
`
`\C
`~
`-....l
`rJl
`d
`
`Ul
`0 .....
`Ul
`.....
`1J1 =(cid:173)
`
`('D
`('D
`
`FIG. 5
`
`VTL -Erased lead -recording
`
`T -Recording portion (track)
`
`Vr -Lead time (recordings still stored)
`
`T2
`,---
`
`T1
`
`T3
`I
`1 ____ ----JL_ _____ ~ ----....
`
`/
`
`-
`
`-
`
`~--
`/
`_,:/
`
`,-:::-
`
`/
`
`I I I I
`
`I I I,,.,~
`
`I I
`
`I I I
`
`,,,,,
`
`,,:-./
`
`//
`/,./
`
`//
`
`/
`I ·I
`
`l:'l!:~-~d w
`
`STOP REC
`
`REC
`
`STOP
`
`?' ....
`
`('D
`""f'j
`
`0
`0
`N
`'"o
`
`"°
`
`~ = ~
`
`~
`~
`~
`•
`00
`~
`
`Recording + storage
`
`L~R _~=al time
`
`-
`
`I ! ) I I
`
`/
`
`STOP
`
`/
`I I I
`
`/
`
`/
`
`I
`~ /
`I _L_,
`
`/
`
`/
`
`/
`
`I
`
`/
`//
`I
`
`fr'
`
`I
`
`-H~l-~-t-l~-1-t
`
`~\~~---~
`
`REC
`
`J ___ T
`/
`
`I
`
`I
`
`I
`
`I
`
`I
`
`

`
`US 7,490,037 B2
`
`1
`METHOD AND APPARATUS FOR ENCODING
`SIGNALS
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`
`This application claims priority of PCT Application Serial
`No. PCT/EP98/03981 filed Jun. 30, 1998, German Applica(cid:173)
`tion 197 27 938.4 filed on Jul. 1, 1997 and is a continuation
`application of U.S. patent application Ser. No. 09/462,049
`filed on Apr. 3, 2000 now abandoned.
`
`BACKGROUND OF THE INVENTION
`
`a) Field of the Invention
`The invention concerns a method of encoding signals, in
`particular digitized audio signals, with an encoding device for
`encoding the signal in an encoding format and a processing
`device for processing the encoded signal.
`b) Description of the Related Art
`Methods of that kind are known for example from Euro(cid:173)
`pean patent specification No 290 581. In that case, in the bit
`rate-reducing encoding of audio signals which are already
`present in digitized form, for example 48 kHz sampling fre(cid:173)
`quency/16-bit resolution, psycho-acoustic phenomena of the
`perception of audio signals are used in such a way that the
`original bit rate of the audio signals is considerably reduced.
`Such methods are also familiar and standardized under the
`heading of 'source encoding' (ISO 11172 and 11318).
`With some encoding methods there is also the option of
`encoding the signal in a given transmission or storage format
`in order then to be able to transmit and/or store the signal.
`That encoding however frequently gives rise to the necessity
`for the signals to be re-coded in regard to the transmission or
`storage format used as the transmission channel which is then
`actually employed or the storage device which is actually
`used employs another encoding format. If the necessary re(cid:173)
`coding algorithms for re-coding the signal for adaptation to
`the actual encoding format are not available, the result of this
`is that complete decoding of the signal into a linear, non-data(cid:173)
`reduced format and subsequent encoding to the desired for(cid:173)
`mat have to be implemented. That frequently results in quality
`losses of greater or lesser severity. Either that expensive path
`is adopted or adaptation is not possible.
`
`OBJECT AND SUMMARY OF THE INVENTION
`
`The primary object of the present invention is to provide a
`method of the kind set forth in the opening part of this speci- 50
`fication, which resolves the above-indicated problems and in
`which re-coding operations, once encoding has been effected,
`are very substantially avoided.
`In accordance with the invention that object is attained in
`that, in a method of the kind set forth in the opening part of
`this specification, the encoding format is determined in
`dependence on the properties of the processing device.
`With the method according to the invention it is particu(cid:173)
`larly advantageous that encoding is already effected at the
`transmission end, taking account of the properties of the
`connected devices for subjecting the signals for further pro(cid:173)
`cessing. In other words, it is already possible in the encoding
`procedure to take account of and use the encoding formats
`which are necessary for the connected items of equipment. In
`particular by means of the present method it is possible to
`implement encoding which is adapted to the possibilities of
`the selected transmission channel and decoding at the recep-
`
`2
`ti on end, so that the signal can be transmitted and received or
`decoded at the maximum possible quality.
`Furthermore the method according to the invention makes
`it possible in any case to avoid expensive re-coding of the
`encoded signal as the signal is encoded from the outset in the
`correct format, that is to say the format which corresponds to
`the connected items of equipment, for example the connected
`storage device or the connected transmission channel. The
`method therefore not only permits higher-quality transmis-
`10 sion of signals but also faster transmission.
`A particularly advantageous embodiment of the invention
`is distinguished in that, prior to establishing the encoding
`algorithm, the properties or the property parameters of the
`selected transmission and/or storage and/or decoding devices
`15 are ascertained by one or more test signals directed to the
`corresponding device. In that way by virtue of the method
`according to the invention it is possible for the encoding
`format to be used or the encoding algorithm to be applied to
`be directly adapted to the devices which are actually con-
`20 nected in each case, such as for example transmission chan(cid:173)
`nels, storage means or decoding devices at the reception end.
`With the method according to the invention therefore, a per(cid:173)
`son who would like to transmit signals, by virtue of the test
`signal, no longer needs to establish or make adjustments for
`25 connected items of equipment which are involved, such as for
`example transmission channel, storage device or decoding
`devices at the reception end, when that person would like to
`transmit or send signals. With the solution according to the
`invention however it is possible, prior to the actual encoding
`30 by hand, to preset the corresponding parameters for selection
`of the desired encoding format in order for example to permit
`transmission even with devices which are not recognised by
`means of the test signal. In any case therefore the method
`according to the invention permits adaptation of the encoding
`35 format to the items of equipment used.
`If the signal to be sent is a digitized audio signal and the
`signal is present in source-encoded form, that is to say in bit
`rate-reduced form, the method according to the invention
`makes the following possible: if transmission and/or storage
`40 devices of various capacities are available, then, having
`regard to the amount of data which is still to be transmitted
`after bit rate-reduced encoding, it is possible to select a trans(cid:173)
`mission channel which enjoys appropriate capacity or a stor(cid:173)
`age device which enjoys appropriate capacity. Thus for
`45 example in the case of signals of relatively low quality or
`when the demands in terms of reception quality are relatively
`low, that is to say with a higher level of redundancy, it is
`possible to adopt a transmission channel of lower capacity
`and thus possibly save cost.
`The invention is used for example in regard to transmission
`or storage of data-reduced audio signals which are present for
`example in the formats G.711, G.722, MPEG 1h-layer 1, 2, 3
`or MPEG 4. The invention can be applied to all systems, for
`example, transformation and subband encoding methods,
`55 adaptive and non-adaptive pulse code modulation methods,
`with linear and non-linear quantization, combinations thereof
`and other audio encoding methods.
`The invention also makes use of certain properties of such
`methods. Typically audio signals which are to be transmitted
`60 or stored and which are data-reduced require only a low
`transmission or storage capacity. The result of this is that
`audio signals can be transmitted even over narrow-band lines
`in real time. In that case the data rate of the audio signals is so
`selected that they satisfy either the qualitative claims or the
`65 economic and commercial requirements. A high data rate has
`a correspondingly high quality, on the other hand it also
`requires a larger channel or storage capacity, which in turn
`
`

`
`US 7,490,037 B2
`
`3
`gives rise to higher costs. When dealing with very narrow(cid:173)
`band transmission channels, if wide-band channels are not
`available, the transmission of high-quality audio signals, that
`is to say audio signals having large quantities of data, are
`implemented in an n-times real time with n> 1.
`Therefore a particularly preferred embodiment of the
`invention is one in which bit rate-reduced audio signals are to
`be sent and a plurality of transmission channels and/or bit
`rates are available for transmission of the audio signals. Then,
`by virtue of the method according to the invention, the trans- 10
`mission charmel and/or the bit rate in the transmission of the
`audio signals can be selected in such a way that the audio
`signal can be transmitted in real time or even faster than real
`time.
`Advantageous developments and configurations of the 15
`method according to the invention are set forth in the appen(cid:173)
`dant claims.
`Another object of the present invention is to provide an
`apparatus for encoding signals, which avoids the problems set
`forth in the opening part of this specification and in which 20
`re-coding of the signal after encoding has been effected is no
`longer necessary.
`In accordance with the invention that object is attained by
`an apparatus for encoding signals, having a control device
`which presets the encoding format to be used for the encoding 25
`operation in dependence on the properties of a processing
`device for subsequent processing of the signals.
`The advantage of the apparatus according to the invention
`is that the encoding format takes account from the outset of
`further processing, that is to say for example transmission or
`storage of the signal. That means that the signal cannot
`undergo incorrect encoding in the sense that the signal is
`encoded in an encoding format which does not suit the
`selected transmission or further processing devices, such as
`for example a storage device.
`In a particularly preferred embodiment of the invention it is
`possible by means of a control device having a test signal
`generator which emits a test signal, by means of which the
`control device establishes the properties of the connected
`device, thus for example the bit rate of the connected trans(cid:173)
`mission channel, suitably to automatically select the encod(cid:173)
`ing format by means of the control device. The user therefore
`does not need to intervene manually in the procedure for
`selecting the desired encoding format. That therefore advan(cid:173)
`tageously affords a considerable simplification in operation.
`For, on the one hand there is now no need for manual setting
`of the encoding format and in addition the user of the appa(cid:173)
`ratus is not embarrassed even ifthat person-for example as
`a lay person--does not have the appropriate knowledge about
`the transmission charmel or the decoding options at the recep(cid:173)
`tion end. The invention is therefore distinguished in particular
`by its user-friendliness.
`In a further embodiment of the invention, provided at the
`control device is a display input device which makes it pos(cid:173)
`sible for a user to preset an encoding format to be used. It is
`thus possible to select the correct encoding format even when
`the format suiting the selected transmission device or storage
`device or decoding device is not known and also detection by
`means of the test signal is not possible. It is particularly 60
`preferred in that respect that the user can select from prede(cid:173)
`termined formats; it is however also possible for the user to
`completely freely preset a given encoding procedure or even
`entirely prevent an encoding procedure.
`Further advantageous embodiments of the apparatus 65
`according to the invention are set forth in the appendant
`claims.
`
`4
`The invention will now be described in greater detail by
`means of an embodiment with reference to the accompanying
`drawings.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`In the drawings:
`FIG. 1 is a block circuit diagram of the structure at the
`transmission end of an embodiment of the apparatus accord(cid:173)
`ing to the invention for the encoding of signals or a possible
`implementation of the method according to the invention;
`FIG. 2 is a block circuit diagram of a decoding and storage
`device at the reception end for further illustrating the inven(cid:173)
`tion;
`FIG. 3 is a block circuit diagram of the apparatus according
`to the invention;
`FIG. 4 is a diagrammactic view of the input device of the
`apparatus shown in FIG. 3; and
`FIG. 5 is a time-presentation diagram of an audio record(cid:173)
`ing.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`FIG. 1 shows a block circuit diagram of the structure at the
`transmission end of an installation for carrying into effect an
`embodiment of the method according to the invention. Refer-
`30 ring to FIG. 1, a digitized monophonic audio signal TE is
`passed to one of the available encoding algorithms Cl or C2,
`according to a switch position of a switch Sl. The output
`signal T Eel or T Ec2 of the encoding algorithm stage Cl or C2
`respectively is passed to transmission charmels Ul or U2 or a
`35 storage unit SP, according to a switch position of switches S2 a
`and S26 . The signal T Eel or T Ec2 stored in the storage unit SP
`can be passed at a later time to one of the transmission chan(cid:173)
`nels Ul or U2. The control of the switches Sl, S2 a and S26
`regulates a control unit K in dependence on properties or
`40 parameters of the desired encoding format, which are set at a
`user interface N serving as an input/display device and/or
`stored in a parameter storage means M. In addition the control
`unit K can control the switches Sl, S2 a and S26 in dependence
`on a test signal previously sent to the lines Ul or U2 respec-
`45 tively or to the storage device SP. The test signal gives the
`control unit K the information about the properties or param(cid:173)
`eters of the channels Ul or U2 or the storage device SP. For
`signal communication between the storage device SP and the
`control unit K, an additional direct connection K-SP can be
`50 made. With those items ofinformation, the control unit K then
`selects the encoding format Cl or C2 corresponding to those
`properties or parameters, by suitably positioning the switch
`Sl. Thus in particular the parameter bit rate of the encoding
`algorithm stage Cl or C2 is set by the control unit K in
`55 dependence on the parameters set at the user interface N
`and/or the parameters stored in the parameter storage means
`Mand/or the necessary parameters, which are detected by the
`test signal, for the transmission channels Ul and U2 respec-
`tively.
`A user can select by means of the user interface N receiver
`parameter sets El, E2 or E3 (not shown), using a switch (not
`shown) and read out the data thereof, for example bit rate,
`transmission charmel and possibly also encoding algorithm,
`from the parameter storage means M. By means of the user
`interface N the user can also alter and store or override the
`parameters of the receiver parameter sets so that the param-
`eters of the interface N and not those of the parameter storage
`
`

`
`US 7,490,037 B2
`
`5
`means are used. That may be necessary by virtue of the
`current transmission and/or storage to be implemented.
`To illustrate the invention FIG. 2 shows a block circuit
`diagram of a device at the transmission end. In regard to the
`parameters used there this device corresponds to the receiver
`parameter set El from FIG. 1. The output signal TAci of the
`transmission channel Ul is passed to the decoding algorithm
`stage Dl and there decoded in accordance with the decoding
`specification. Alternatively or simultaneously the output sig(cid:173)
`nal TAci of the transmission channel Ul can also be passed to
`the storage unit SP. The output signal of the decoding algo(cid:173)
`rithm stage TA is a digitized monophonic audio signal.
`By virtue of the method according to the invention the
`decoding algorithm of the decoding algorithm stage Dl was
`established for example by the control unit K by a test signal
`sent to the decoding algorithm stage. Encoding (see FIG. 1)
`was therefore implemented in a mode adapted to the detected
`decoding algorithm stage. Decoding is thus effected by Dl
`without any problems, at the reception end.
`The invention further concerns firstly a recording, process(cid:173)
`ing and transmission apparatus of a first type for the storage,
`processing and transmission of audio signals, with an analog
`audio signal input, in particular a microphone or a micro(cid:173)
`phone input connection, a converting device for processing
`analog audio signals to digital audio data and a storage
`medium for the storage of the digital audio data; secondly a
`recording, processing and transmission apparatus of a second
`type for the storage, processing and transmission of audio
`data, with an input connection for digital audio data and a
`storage medium for the storage of the digital audio data; and
`thirdly a reproduction apparatus for the reproduction of audio
`signals with a headset or headset connection, a converting
`device for processing digital audio data to analog audio sig(cid:173)
`nals and a storage medium for the storage of the digital audio
`data.
`Apparatuses of that kind, in which analog signals are digi(cid:173)
`tized and then stored on a digital storage medium are known.
`Such apparatuses can generally also record audio data which
`are fed in digitally, directly on to the digital storage medium.
`Such apparatuses are also known, in which the digitally 40
`stored audio data can be reproduced after digital/analog con(cid:173)
`version by way of an analog audio output, in particular a
`headset or a headset connection.
`Apparatuses of that kind are used with different functional
`extents for example in the hi-fi sector. Depending on the 45
`equipment involved in the apparatus hi-fi devices of that kind
`are suitable for recording, processing and/or reproducing the
`audio signals. Different storage media are required, depend(cid:173)
`ing on the recording standard used. When using the DAT(cid:173)
`standard (Digital Audio Tape) and the DCC-standard (Digital 50
`Compact Cassette) the storage medium for storage of the
`digital and data-reduced audio data is a magnetic tape. In the
`case of a further standard, the MD (Mini-Disk), magneto(cid:173)
`optical storage disks as storage media are used for storage of
`the digital audio data which are data-reduced from psycho- 55
`acoustic points of view.
`With the recording, processing, transmission and repro(cid:173)
`duction apparatuses of the general kind set forth, the audio
`signals are stored in digitized form on the storage medium and
`can be processed and/or handled by playback with simulta- 60
`neously fresh recording by means of a further apparatus. The
`storage medium on which the audio data are stored can be
`removed from the apparatus and kept for later use if the stored
`audio data are not required for the time being. Fresh audio
`data can be stored by erasing and playing over audio data 65
`which are no longer required or using a storage medium
`which has not yet been used.
`
`6
`For the situation where the stored audio data are required at
`another location, the situation is mainly that the storage
`medium such as for example the cassette or disk is taken to the
`desired location. When it has arrived there the storage
`medium is inserted into a suitable reproduction apparatus so
`that the stored digital audio data can be processed or repro(cid:173)
`duced after digital/analog conversion as analog audio signals.
`The object of this further invention is to develop the appa(cid:173)
`ratuses of the general kind set forth, in such a way that in
`10 particular processing and transmission of audio data are
`accelerated and operation of the apparatus is facilitated.
`In the recording, processing and transmission apparatuses
`and in the reproduction apparatus of the kind set forth above,
`in accordance with the invention that object is attained in that
`15 the storage medium is intended for constantly remaining in
`the respective apparatus and the apparatus has a respective
`interface for transmission of the digital audio data to a pro(cid:173)
`cessing device which is external to the apparatus.
`The advantages of this invention are in particular that the
`20 audio data can be transmitted by way of the interface in a
`simple fashion. In that respect, in a first step the digital audio
`data can be transmitted to a computer in order then in a second
`step to be communicated by way of a data remote transmis(cid:173)
`sion line or by means of an electronic mail system to locations
`25 which are further away. By virtue thereof it is advantageously
`no longer necessary for the storage medium itself to be trans(cid:173)
`ported from one location to the others. The period of time
`from the moment of recording an audio signal, for example by
`means of an apparatus of the first or second type, to the
`30 moment of reproducing the recorded audio signal, for
`example by means of an apparatus of the third type, is con(cid:173)
`siderably reduced. In addition there is no longer the danger
`that the storage medium suffers damage or is lost during
`transportation of the audio data.
`The design according to the invention can be carried into
`effect with a cable-less or cabled interface.
`In addition the apparatus according to the invention saves
`on numerous precision-engineeredcomponents which permit
`interchange of the storage medium in the case of the known
`apparatuses. The manufacturing cost of the apparatus is
`reduced by virtue of the saving on the precision-engineered
`components. At the same time the level of reliability of the
`apparatus is increased as in particular the precision-engi(cid:173)
`neered components of an apparatus are the cause of failures
`and problems.
`In a preferred embodiment the apparatus according to the
`invention of the first type has an analog high level input
`connection and/or a digital input connection for audio signals.
`Those connections make it possible for the apparatus accord(cid:173)
`ing to the invention also to record, process and transmit sig(cid:173)
`nals from the conventional analog or digital recording and
`reproducing apparatuses.
`In a particularly preferred embodiment, the apparatuses
`according to the invention of the first and second types have a
`converting device for processing digital audio data to analog
`audio data in order to permit reproduction of the stored digital
`audio data as analog audio signals.
`In a desirable development the apparatuses according to
`the invention have a headset or at least one headset output
`connection so that the stored audio data, after digital/analog
`conversion, can be acoustically reproduced.
`The required storage space for storage of the digital audio
`data can be reduced in a particularly preferred fashion by the
`digital audio data being converted into a data-reduced format.
`For that purpose the apparatuses according to the invention
`have a converting device for converting the digital audio data
`
`35
`
`

`
`US 7,490,037 B2
`
`8
`stream-disposed headset amplifier 21 or a line-out output
`connection 23 and a headset output connection 22.
`A microphone signal at the microphone input connection
`11 is raised by the microphone pre-amplifier 13 to the level
`which is typical for the line-in input connection 9. The first
`change-over switch 15 selects whether the microphone signal
`or the signal at the line-in input connection 9 is passed along
`as the input signal. The first change-over switch 15 is con(cid:173)
`trolled by a microcontroller 25 which is to be functionally
`10 associated with the digital interface region 7. The input ampli(cid:173)
`fier 17 serves for level setting of the input signal, the level of
`the input signal being effected by means of a level control 18
`in the input amplifier 17, byway ofthemicrocontroller25. In
`that case a downstream-disposed peak LED 27 can warn of
`15 overdriving of a downstream-disposed analog/digital con(cid:173)
`verter 29 which belongs to the digital signal processing region
`5.
`
`35
`
`7
`into a data-reduced format, for example in accordance with
`the MPEG, AAC, AC3 or ATRAC-standard.
`The preferred embodiments described hereinafter relate
`both to the recording, processing and transmission appara(cid:173)
`tuses according to the invention of the first and second types
`and also the reproduction apparatus according to the inven(cid:173)
`tion.
`In the apparatuses according to the invention the storage
`medium is preferably a flash-RAM or a dynamic RAM. Fur(cid:173)
`ther precision-engineered components are saved by virtue of
`using RAM-units of that kind. That means that the level of
`reliability of the apparatuses is further enhanced for the rea(cid:173)
`sons set out above. In addition, the use of RAM units makes
`it unnecessary to use a motor for transporting a magnetic
`storage tape or a magneto-optical disk so that energy can also
`be saved during operation.
`The interface for cable-less transmission of the digital
`audio data to a processing device which is external to the
`apparatus is particularly preferably provided for bi-direc(cid:173)
`tional data transmission. It is thus possible to transmit not 20
`only digital data from the apparatuses to external processing
`devices but also from the external processing devices to the
`apparatuses according to the invention.
`Preferably the interface is an infra-red interface which
`affords a high data transmission rate with at the same time 25
`good transmission quality.
`In a further preferred embodiment of the apparatuses the
`digital audio data are stored in the data-reduced format in the
`storage medium. That permits better utilisation of the storage
`capacity present in the storage medium. Particularly prefer- 30
`ably, the digital audio data are also transmitted in the data(cid:173)
`reduced format by way of the cable-less transmission inter(cid:173)
`face. That markedly speeds up the transmission of the audio
`data to a processing device which is external to the apparatus.
`In addition preferably provided on the apparatuses is an
`analog high level output connection and/or digital output
`connection for audio signals. That permits data transmission
`in analog or digital form to known recording and reproducing
`apparatuses.
`Preferably the apparatuses according to the invention also
`have a converting device for decoding data-reduced audio
`data so that, besides data reduction prior to storage of the
`audio data, decoding of the data-reduced audio data is also
`possible before same are transmitted to the digital output
`connection or to the digital/analog processing unit.
`For the input of control commands for controlling the
`apparatuses, the apparatuses according to the invention pref(cid:173)
`erably have an input device. The apparatuses also preferably
`have a display device for displaying corresponding items of 50
`status or control information.
`So that the recording, processing and transmission appa(cid:173)
`ratuses according to the invention and the reproduction appa(cid:173)
`ratus according to the invention can be used in a versatile
`manner, they are advantageously of a portable configuration, 55
`in a light compact casing.
`The apparatus 1 illustrated in FIG. 3 includes three appa(cid:173)
`ratus regions, more specifically an analog signal processing
`region 3, a digital signal processing region 5 and a digital
`interface region 7.
`The analog signal processing region 3 includes a line-in
`input connection 9, a microphone input connection 11 which
`is connected to a microphone pre-amplifier 13, a first change(cid:173)
`over switch 15 with which a downstream-disposed input
`amplifier 17 is connected either to the microphone pre-am- 65
`plifier or the line-in input connection, a second change-over
`switch 19 with which a source can be selected for a down-
`
`40
`
`45
`
`The second change-over switch 19 which is also controlled
`by way of the microcontroller 25 selects which analog signal
`is passed to the headset amplifier 21 and at the same time the
`line-out output connection 23. This can be either the signal
`coming from the input amplifier 17 or the analog signal of a
`digital/analog converter 31 which is also a component of the
`digital signal processing region 5.
`The headset amplifie