IVI LLC EXHIBIT 2009
`XILINX V. IVI LLC
`IPR Case 2013-00029
`
`

`

`5,537,436
`
`Page 2
`
`OTHER PUBLICATIONS
`
`"Speech—band data modems". Electronics J: Power. v01. 26,
`No. 9, by P. F. Adams. pp. 733—736.
`”Speech and Data Transmission in ACS Telephone Chan-
`nels“, Tefecommunicanon xi Radio Eng, v01. 30/31. Jul.
`1976, by V. E. Bukhviner. pp. 66—?0.
`
`“Method for superimposing Dam on Amplitude—Modulated
`Signals“, Electronics 1mm. vol. IS. NO. 9, Apr. 29. 1982.
`by Lockhan eL 31. pp. 379—381.
`“A New Generation of Speech Plus Data Multiplexer",
`Conference on Communicarions and Equipment and Sys-
`tem, Birmingham. England. Apr. 4—7. I978, by N, N, Y.
`Shum el al, pp. Ill—113.
`
`

`

`US. Patent
`
`Jul. 16,1996
`
`Sheet 1 of 13
`
`5,537,436
`
`mo
`
`FIG.
`
`7
`
`PRIOR ART
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`

`US. Patent
`
`Jul. 16,1996
`
`Sheet 2 of 18
`
`5,537,436
`
`FIG. 3
`
`FIG. 4
`
`
`
`
`
`

`

`US. Patent
`
`Jul. 16, 1996
`
`Sheet 3 of 18
`
`5,537,436
`
`FIG. 6
`
`SIGNAL 90
`
`ANALOG
`
`DIGITAL
`SIGNAL
`
` ORTHOGONAL'
`MODULATOR I
`
`FIG. 7
`
`

`

`US. Patent
`
`Jul. 16,1996
`
`Sheet 4 of 13
`
`5,537,436
`
`FIG. 8
`
`
`
`
`SPECTRUM 0F SIGNAL 53 ADDED TO SIGNAL 53
`
`fiPECTRUH 0F SIGNAL 52 ADDED TO SIGNAL 62
`
`
`
`ENERGY
`
`DETECTOR
`
`
`
`

`

`US. Patent
`
`Jul. 16,1996
`
`Sheet 5 of 18
`
`5,537,436
`
`21 D
`
`230
`220)
`
`240-1
`
`
`
`DE-MAPFER
`
`DEMODULATOR
` 2-T0-1
`
`DE-iflPPER
`
`210
`
`230
`
`220‘
`
`250
`
`
`ADAPTIVE
`FILTER
`
`
`n
`DE-MAPPER DIGI‘ML
`STREAM
`
`2N5
`
`
`
`295
`
`2-T0— 1
`
`DE-MAPPER
`
`

`

`US. Patent
`
`Jul.16, 1996
`
`Sheet 6 of 13
`
`5,537,436
`
`FIG.
`
`12
`
`20
`
`30
`
`#0
`
`50
`
`51
`
`PRE-
`
`ms
`
`53
`
`l-T0-2
`
`.1
`
`ORTHDGONAL
`MODULATOR
`
`50
`
`HAPPER
`
`90
`
`320
`
`ECHO
`
`CANCELUER
`
`HYBRII
`
`Gm
`
`230
`
`g 220
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`210
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`
`0151111 DE—MAFPER
`5m
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`2?6
`
`N5
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`A
`
`2-10-1
`
`DE—MAPPER- DE‘HUX I
`
`SYHBOL
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`
`ADAPHYE
`
`nauonumoa
`
`29“
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`UPDhTE
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`- u
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`p
`
`

`

`US. Patent
`
`Jul. 16,1996
`
`Sheet 7 of 13
`
`5,537,436
`
`FIG. 13
`
`ANALOG
`
`SIGNAL
`
`”*PPER
`
`DIGITAL
`SIGNAL
`
`HARPER
`
`
`
`CARRIER
`o FREQUENCY
`
`ROTATDR
`
`
`
`
`
`
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`I
`
`Tx HlLBERT
`PASSBAIII)
`FILTER
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`PASSBAND
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`fl
`
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`
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`FILTER
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`o
`
`ECHO
`CARCELLER
`
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`AL
`
`SICIIAL
`SPACE
`DECODER
`
`
`
`"7
`
`i
`
`CARRIER
`RRASE
`COLLECTOR
`
`EQUALIZER
`
`Rx HILBERT
`
`PASSBAIID
`
`
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`FILTER
`FREQUENCY
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`
`Rx HILBERT
`RomoR
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`PASSBAND
`
`FILTER
`
`ANALOG
`
`lo
`Ila
`
`FIG.
`
`74
`
`
`
`

`

`US. Patent
`
`Jul. 16, 1996
`
`Sheet 3 of18
`
`5,537,436
`
`F]G.
`
`72
`1 5
`
`
`
`
`PSEUDO-RAHDOM
`GENERATOR
`
`
`
`FIG. 17
`
`ANALOG
`SIGNAL
`
`57
`
`55
`
`
`
`
`ANALYSIS
`”NEAR
`PREDICTIOH
`””5“
`COEFFICIENT
`TRANSMITTED
`
`SIGNAL
`GENERATOR
`PREDICTOR COEFFICIENTS
`svn
`
`
`DIGITAL
`SYSTEM
`
`
`SIGNAL
`
`
`
`
`
`
`RESIDUAL
`
`53
`
`OUTPUT
`RECEIVED
`
`
`RESIDUAL o
`ANALOG SIGNAL
`
`
`RECEIVED
`PREDICTION
`SYNTHESIS
`SIGNAL
`COEFFICIENTS
`
`
`
`
`SVD SYSTEM
`h
`FILTER
`
`59
`
`
`
`OUTPUT
`DIGITAL SIGNAL
`
`

`

`US. Patent
`
`Jul. 16, 1996
`
`Sheet 9 of 13
`
`5,537 ,436
`
`FIG. 18
`
`TR HlLBERT
`
`Tx HlLBERT
`
`FILTER
`HYBRID
`
`
`LTER
`
`F1
`
`
`ECHO
`o
`CANCELLER
`
`CARRIER
`FREQUENCY
`ROTATOR l
`
`lI
`
`4
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`
`TX SIGNAL
`SPACE
`SELECTOR
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`
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`
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`
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`COUNTER
`
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`
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`SIGNAL SPACE
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`
`412
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`
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`SIGNAL SPACE
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`
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`SIGNAL SPACE
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`
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`
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`SWITCH
`
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`
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`
`
`
`
`ANALOG-ONLY
`
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`
`SIGNAL SPACE
`
`SPACE
`
`DECODER
`SELECTOR
`
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`
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`
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`DECODER
`
`
`
`
`
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`
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`SPACE
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`
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`
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`SELECTOR
`DECODER
`
`
`
`
` Rx HILBERT
`
`
`FILTER
`
`Rx HILBERT
`
`CARRIER
`
`
`FREQUENCY
`
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`
`
`FILTER
`
`425
`
`
`
`

`

`US. Patent
`
`Jul. 16, 1996
`
`Sheet 10 of 13
`
`5,537,436
`
`FIG. 19
`
`
`SUPPORT
`CENTER
`
`SOFTWARE
`
`
`
`CUSTOMER‘S SITE
`
`

`

`US. Patent
`
`Jul. 16, 1996
`
`Sheet 11 0f18
`
`5,537,436
`
`FIG. 20
`
`TECHNICAL SUPPORT
`CENTER
`
`5I
`
`fI*
`
`T
`
` CUSTOMER'S SITE
`
`
`
`SYSTEM
`
`
`
`

`

`US. Patent
`
`Jul. 16, 1996
`
`Sheet 12 of18
`
`5,537,436
`
`F1G. 2 7
`
`CUSTOMER‘S SITE
`
`SVD DATA-PHONE
`
`
`
`
`COMPLEX
`SYSTEM
`
`
`
`TO OTHER USER SYSTEMS
`
`I
`.5
`
`5
`‘l
`
`1
`¢
`
`CUSTOMER
`SUPPORT
`CENTER
`
`
`
`

`

`US. Patent
`
`Jul.16,1996
`
`Sheet 13 0f 18
`
`5,537,436
`
`FIG. 22
`
`HOHE AGENT
`
`%
`
`f
`
`{
`I:
`
`HOME
`
`
`
`‘
`
`a;
`
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`
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`
`
`
`
`
`
`
`PBX/
`
`FSTN
`
`
`CALL =
`HUNT GROUP
`
`ROUTINES
`
`CUSTOMER
`
`

`

`US. Patent
`
`Jul. 16, 1996
`
`Sheet 14 of 18
`
`5,537,436
`
`FIG. 23
`
`GAME PLAY #1 HOUSE
`
`GAME PLAYER #1
`
`
`
`GAME PLAY #2 HOUSE
`
`GAME FLAYER # 2
`
`
`
`

`

`US. Patent
`
`Jul. 16, 1996
`
`Sheet 15 of 18
`
`5,537,436
`
`FIG. 2 4
`
`T0
`TELEPHONE
`NETWORK
`
`434
`
`440
`PM
`
`VIDEO CARD
`
`
`
`
`
`

`

`US. Patent
`
`Jul. 16, 1996
`
`Sheet 16 of 18
`
`5,537,436
`
`
`
`FIG. 29
`
`

`

`US. Patent
`
`Jul. 16,1996
`
`Sheet 17 0f18
`
`5,537,436
`
`FIG. 30
`
` ANALOG
`
`TELEPHONE
`
`NETWORK
`
`DIGITAL
`
`

`

`US. Patent
`
`Jul. 16, 1996
`
`Sheet 18 of 18
`
`5,537,436
`
`FIG. 3 1
`
`(505
`
`_PEECH
`
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`
`
`
`
`TEXT
`OUTPUT
`
`
`DEVICE
`
`DIGITAL PATH
`
`

`

`1
`SINIULTANEOUS ANALOG AND DIGITAL
`COMMUNICATION APPLICATIONS
`
`RELATED APPLICATION
`
`This application is related to an application titled SIMUL-
`TANEOUS ANALOG AND DIGITAL COMMUNICA-
`TION. filed on even date hereof.
`
`FIELD OF THE INVENTION
`
`This invention relates to simultaneous transmission of
`analog and digital signals and. more particularly. to appli—
`cations that employ simultaneous transmission of analog
`signals and digital signals in a non-multiplexed manner and
`in a generally canextensive frequency band.
`
`DESCRIPTION OF THE PRIOR ART
`
`In the prior art. when voice and data is transmitted
`simultaneously over a channel,
`it
`is typically transmitted
`either via frequency—division multiplexing or time—division
`multiplexing, In frequency-division multiplexing. the data
`channel and the voice channel are allocated different sub—
`bands of the channel‘s bandwidth. Examples of that are US.
`Pat. Nos. 4,757,495. 4,672,602, and 4,546.212. In time-
`division multiplexing arrangements, voice signals
`are
`sampled. digitized and interleaved with digital data to form
`a single information stream which is communicated over the
`available channel. Praetically every digital carrier system
`(e.g. the T] carrier System) is an example of that.
`US Pat. No. 4,512,0I3. issued Apr. 16, 1985, presents an
`interesting approach that is close to a frequency division
`multiplexing arrangement for simultaneous voice and data.
`The arrangement filters the speech signal and adds thereto a
`modulated narrowband signal to form the transmitted signal.
`The narrowband modulated signal derives from a narrow—
`band digital
`input signal
`that is modulated with a carrier.
`thereby shifting the narrow—band up in frequency to a
`position in the spectrum where there is little speech energy.
`At the receiver, in reliance of the fact that the speech power
`is low in the narrowband occupied by the modulated digital
`signal, the digital signal is recovered through appropriate
`demodulation. Thereafter. the recovered digital signal
`is
`remodulated to replicate the transmitter's operation, adap-
`tivcly filtered to account for channel characteristics. and
`subtracted from the received signal. The result
`is the
`received speech. As indicated abOve. one salient character-
`istic of that arrangement. as stated in col. 2, lines 13-18, is
`that “ .
`.
`. an entire analog speech signal and a modulated
`data signal are capable of being transmitted over a normal
`analog channel by the multiplexing of the data signal within
`the portion of the normal analog speech signal frequency
`band where the speech signal
`is present and the power
`density characteristic thereof is low". As an aside.
`the
`4,517,013 arrangement is half duplex.
`1n the modern art. digital information is communicated
`over a channel by converting the digital
`information to
`analog form.
`in the most basic form, a modem filters the
`digital signal (i.e.. shifts it in frequency) to form a band-
`Iimited signal and modulates that signal to reside within the
`passband of the communication channel. In telephony. for
`example, that passbartd may be between 300 Hz and 3500
`Hz. To increase the infonnation-carrying capacity of the
`modulated signal, more sophisticated modems employ
`quadrature modulation. Quadrature modulation is often
`depicted as a two—dimensional signal space. Use of the
`
`5,537,436
`
`2
`
`signal space to send voice information is disclosed in US.
`Pat. No. 5,081,647 issued Ian. 14, 1992.
`Use of the signal space to send data and voice is described
`in ”High Speed Digital and Analog Parallel Transmission
`Technique Over Single Telephone Channel“. Akashi et a].
`IEEE Transactions on Communications, V01. 30, No. 5. May.
`1982. pp. 1213—1218. Unlike prior techniques. where analog
`and data were segregated into different time slots (TDM) or
`difl'ercnt frequency bands (FDML they describe separating
`analog and data signals into the two different channels ofthe
`QAM system. That is, Akashi et al suggest modulating the
`in-phase channel with the analog signal, and modulating the
`quadrature channel with the data signal. Building on that
`description and concerning themselves with channel equal-
`ization, Lim et al analyze equalizer performance in "Adap-
`tive Equalization and Phase Tracking For Simultaneous
`Analongigital Data Transmission“. BSTJ, Vol. 68 No. 9,
`Nov 1981, pp. 2039—2063. [The 1981 BSTl article cites the
`information of 1982 lEEE article as “unpublished work”).
`No one has achieved the ability to simultaneously sent
`both data and voice through both channels of a QAM
`system, and no one has achieved the ability to communicate
`both by data and analog. simultaneously. and in full-duplex.
`over a single bi-directiona] bandlimited communications
`channel.
`
`SUMMARY OF THE INVENTION
`
`Analog information and digital information is communi-
`cated concurrently when employing the principles of this
`invention. In general terms. when the communication chan-
`nel is viewed as a multi-dirnettsional space, the digital signal
`is divided into symbols. and the symbols are mapped onto
`the signal space with a preset distance between them. The
`analog signal, generally limited in magnitude to less than
`half the distance separating the symbols,
`is converted to
`component signals and added (i.e.. vector addition} to the
`symbols. The sum signal is then transmitted to the receiver
`where the symbols are detected and subtracted from the
`received signal to yield the analog signal components. The
`transmitted analog signal is recreated from those compo-
`nents.
`
`In one illustrative embodiment, the digital stream entering
`the transmitter section is divided into words. and each word
`is mapped to a pair of Symbol components. The analog
`signal entering the transmitter section is sampled and each
`pair of successive samples forms a set of analog vector
`components. The analog vector components are added.
`respectively. to the symboi components and the component
`sums are QAM modulated to form the output signal. The
`pairs of analog samples can be derived by simply delaying
`the analog signal and sampling both the delayed and the
`undclayed versions.
`At the receiver. the signal is first demodulated and the
`digital signal is detected in accord with standard modulation
`technology. The detected digital signal
`is then subtracted
`from the received signal to form analog samples pairs that
`are combined to reconstitute the analog signal.
`Line equalization. echo—canceling.
`rare—emphasis. and
`other improvements that are known in the modern art can be
`incorporated in various embodiments that employ the prin-
`ciples of this invention.
`
`BRIEF DESCRIPTION OF THE DRAWING
`
`FIG. 1 presents the basic structure of a prior art modem:
`
`5
`
`10
`
`15
`
`25
`
`30
`
`35
`
`45
`
`55
`
`155
`
`

`

`5,537,436
`
`3
`FIG. 2 shows the signal space and an illustrative signal
`constellation for the FIG. 1 system;
`FIG. 3 shows the signal space of a 0AM analog system:
`FIG. 4 shows the signal space ofan alternating digital and
`analog system;
`FIG. 5 shows the signal space of a combined digital and
`analog system;
`FIG. 6 presents one embodiment of a transmitter section
`for a combined digital and analog system;
`FIG. 7 depicts the vector addition that forms the signal
`space of FIG. 5;
`FIG. 8 presents one orthogonal modulation approach;
`FIG. 9 illustrates the arrangements that permit more than
`one analog signal source to be transmitted simultaneously;
`FIG. 10 details the major elements in a receiver respon-
`sive to the FIG. 5 signal space;
`FIG. 11 presents a block diagram of a receiver that
`includes adaptive equalization:
`FIG. 12 presents the block diagram of an entire modern.
`FIG. 13 presents a slightly different embodiment of the
`FIG. 12 modem.
`
`FIG. 14 depicts one structure for scrambling analog
`samples.
`FIG. 15 presents a block diagram of a privacy scrambler
`employing pseudo-random multiplication of the analog
`samples.
`FIG. 16 illustrates a processor 75 being interposed
`between the analog input and the analog port of the modern.
`with the processor being adapted to carry out signal prepro—
`cessing functions, such as linear predictive coding.
`FIG. 17 presents a block diagram illustrating linear pre-
`dictive coding.
`FIG. 18 preSents a block diagram illustrating the altema-
`tive use of diIIerent signal spaces,
`FIG. 19 depicts use of the disclosed modem in connection
`with sofiwarc support.
`FIG. 2|] depicts use of the disclosed modem in connection
`with apparatus diagnosis and maintenance,
`FIG. 2] depicts use of the disclosed modem in connection
`with apparatus diagnosis and maintenance with the modern
`coupled to a wireless base station.
`FIG. 22 shows use of the disclosed modem in connection
`with a call center.
`FIG. 23 shows use of the disclosed modem in an inter-
`active game environment,
`FIG. 24 presents a block diagram depicting use of the
`disclosed modem in an interactive mode with a television
`display.
`FIG. 25 presents the disclosed modern in a PCMCIA
`configuration, adapted for inclusion with wireless apparatus.
`such as a wireless computer.
`FIG. 26 shows use of the disclosed modem in a telephone
`instrument tltat includes video capabilities,
`FIG. 27 shows use of the disclosed modern in a fax
`machine.
`
`FIG. 28 shows use of the disclosed modern in a personal
`computer,
`FIG. 29 shows use of the disclosed modem in a "plain
`old" telephone.
`FIG. 30 presents a block diagram that includes the dis-
`closed modern and means for bypassing the modem when it
`is inoperative.
`
`IO
`
`I5
`
`25
`
`35
`
`45
`
`50
`
`55
`
`65
`
`4
`FIG. 31 illustrates an arrangement for lexu‘speech uses of
`the modem disclosed herein.
`
`FIG. 32 describes an arrangement that may be employed
`in connection with the hearing-impaired. and
`FIG. 33 presents a general block diagram for a multim
`media answering machine.
`
`DETAILED DESCRIPTION
`
`To place this disclosure in context. FIG. 1 presents a very
`basic block diagram of a modem that communicates digital
`data via quadrature modulation tecluiiqucs. Section 100 is
`the modern‘s transmitter section and section 200 is the
`modcm's receiver section. Specifically.
`in the transmitter
`section digital data is applied in FIG. 1 to a l-to-Z mapper
`110, and mapper 110 develops two outputs which typically
`are referred to as the in—phase and quadrature samples. The
`in—phase samples are applied via low pass filter 150 to
`modulator 120, which multiplies the applied signal by a
`carrier—Le, sin to t in FIG. 1. The quadrature samples are
`applied via low pass filter 160 to modulator 130. which
`multiplies the applied signal by a second carrier. The second
`carrier is orthogonal
`to the first carrier. namely. cos to t.
`Filters 151) and 160 must be bandlirnitcd to no more than to.
`in order to avoid aliasing and to at least half the inverse of
`the output sample rate of mapper 110. The output signals of
`modulators 120 and 130 are added in element 140 to develop
`the analog signal of the modem‘s transmitter section.
`In operation. the digital data applied to the FIG. 1 appa-
`ratus is a stream of bits. Element Ill} views the incoming
`signal as a stream of symbols that each comprise a prese-
`lected number of consecutive bits. and maps each symbol
`into an in-phase analog sample and a quadrature analog
`sample.
`Practitioners in the an often describe the operations
`performed in the FIG. 1 apparatus by means of a signal space
`diagram, such as shown in FIG. 2. The it axis curresponds to
`one of the carrier signals (e.g.. cos to t) and the y axis
`corresponds to the other carrier signal [sin to t}. The in—phase
`and quadrature samples delivered by element 110. in effect.
`specify a location in the signal space of FIG. 2. Accordingly,
`the set of possible samples that element 110 can produce
`corresponds to a set of sample points (i.e., a constellation of
`points) in the signal space depiction of FIG. 2. A 4-point
`signal constellation is shown. by way of illustration. in FIG.
`2. It is well known. however. that one can create signal point
`constellations with a larger number of signal points.
`To receive signals that were modulated by the FIG. 1
`apparatus in accordance with the specific constellation
`depicted in FIG. 2. one must only identify whether the
`received signal is in the first. second. third or fourth quadrant
`of the signal space. That means that there exists great
`latitude in the signals that are received, and any received
`signal that is still in the correct quadrant is mapped to the
`correct constellation signal point in that quadrant. Extended
`to other (and perhaps larger] constellations. the signal space
`can be divided into regions and the receiver's decision is
`made with respect to the region in which the received signal
`is located. We call these regions "neighborhood" regions.
`Returning to FIG. 1 and addressing the modem‘s receiver
`section. the modulated signal is applied to demodulator 210.
`Demodulator 210 recovers the in—phase and quadrature
`components and applies them to slicer 22!]. Slicer 220
`converts the in-phasc and quadrature components into sym-
`bols and applies the symbols to demapper 230. De—rnapper
`
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`5,5 37,436
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`5
`230 maps the symbols into bit streams to form the recovered
`digital data stream.
`Absent any signal degradation (such as due to noise added
`in the channel) the signal received by demodulator 110
`would be precisely the same as the signal sent by adder 140.
`and a determination of neighborhood regions in which the
`signal is found (by slicer 220} would be relatively simple
`and error—free. However. noise that is added to the transmit—
`ted signal shifts the received signal in the signal space and
`modifies the input to slicer 220. Stated in other words. a
`noise signal
`that adds to the signal
`flowing through the
`communication channel corresponds to a vector signal in the
`signal space of FIG. 2 that is added to a transmitted sample
`point. That added vector is of unknown magnitude and
`unknown phase. Consequently. added noise converts a trans—
`mitted signal that corresponds to a point in the signal space
`into a region in the signal
`space. This phenomenon is
`depicted in FIG. 2 by circle 11. Some refer to this circle as
`a signal space “noise cloud“ surrounding the transmitted
`signal.
`in order to detect the
`From the above it is clear that
`transmitted signals without errors. the neighborhood regions
`must be large enough to encompass the noise cloud. Since
`the average power of the sent signal is typically limited by
`other considerations. the extent to which the signal constel-
`lation covers the infinite space represented by the it and y
`axes is also limited. This is represented in FIG. 2 by circle
`12. The restriction imposed by circle 12. coupled with the
`restriction on the size of the neighborhood regions that is
`imposed by noise considerations limits the number of trans-
`mitted signal points in the constellation.
`As indicated above. it has been observed that in typical
`modern designs the allowable signal power and the expected
`fidelity of the channel combine to control the constellation
`sine. Less noisy channels allow for larger constellations. and
`larger constellations permit higher digital data throughputs.
`This leads to a totally revolutionary idea of utilizing all or
`essentially all. of the available signal space for the trans—
`mission of information. A transmitter signal space in accor-
`dance with this revolutionary approach is depicted in FIG. 3
`where a plurality of signal points are depicted randomly
`within the signal space. These points are illustrative of the
`various vectors that the transmitter is aIIOwed to send out.
`There are no more ”constellations of points", where a
`decision must be made between constellation points: there is
`only the entirety of the signal space. In other words, rather
`than having digital signals that are mapped onto a fixed
`constellation within a signal space. FIG. 3 depicts analog
`signals that are mapped onto a signal space. When the analog
`signals that form the in-phase component are independent of
`the analog signals that form the quadrature component. the
`viable signal space of FIG. 3 may be rectangular.
`Having recognized the advantages of sending analog
`signals in accordance with the signal space of FIG. 3. the
`next innovation is to alternate between the signal spaces of
`FIG. 2 and FIG. 3. That is. the innovation is to send customer
`analog signals or customer digital signals as the need arises.
`This is depicted in FIG. 4.
`Further, having recognized the advantages of sending
`either analog or digital signals in accordance with the signal
`spaces of FIG. 4. it was discovered that a totally difiercrtt
`communication approach can be taken. that communicating
`both analog and digital signals. can be expressed concur—
`rently. in a combined signal space. This is illustrated in FIG.
`5. where four neighborhoods are identified for illustrative
`purposes. with demarcation borders identified by dashed
`lines 21 and 22.
`
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`According to the FIG. 5 depiction. the analog signals that
`form “signal clouds" around each digital constellation point
`{e.g.. point 31) should be restricted in their dynamic range
`to be totally contained within the neighborth regions.
`Hence. here too there is a trade-oil between constellation
`size [which directly affects digital through—put) and dynamic
`range of the transmitted analog signal
`(which in some
`situations translates to ”resolution“).
`
`FIG. 6 depicts an arrangement that very basically illus—
`trates the principles disclosed herein,
`It includes a l—to—2
`dimensional mapper 60 responsive to digital signals applied
`on line 61. Mapper 60 develops two output signals on lines
`62 and I53. each of which possesses pulses with quantized
`amplitudes that relate to the digital signals arriving on line
`61. FIG. 6 also includes a l-to-2 mapper 50 that responds to
`an applied analog signal on line 51. and it develops two
`output signals on lines 52 and 53. each of which possesses
`pulses with continuous amplitudes that relate to the analog
`signal on line 51. Outputs 52 and 62 are combined in adder
`70 and outputs 53 and 63 are combined in adder 8|]. The
`outputs of adders 7t} and 80 form the components of the
`signals that are represented by the signal space of FIG. 5. As
`in FIG. 1, the outputs of adders Ti] and 80 are applied via low
`pass filters 150 and 160 to modulators 120 and 130 and
`summed in adder 140 to form a modulated signal as is
`typically known in the modern art.
`In FlG.
`ti element 60 is depicted as a l-to-2 mapper.
`However. it should be understood that element 60 can be an
`M—to-N mapper. That is, element 60 can be responsive to a
`plurality (M) of digital signals and it can develop a different
`plurality (N) of output signals. Similarly. element 50 can be
`a .l-to-K encoder that is responsive to a plurality of analog
`signals. Likewise.
`the collection of elements that follow
`elements 50 and 60 (id. elements 70. 80.120. 130. 140.150
`and 160), which form orthogonal modulator 90 can be
`constructed to be responsive to whatever plurality of outputs
`of that elements 50 and 60 are designed to produce (e.g..
`three dimensional space. four dimensional space. etc). More
`specifically.
`those elements must account
`for all of the
`applied input signals. and that means that they must be able
`to handle K or N signals, whichever is larger. in such a
`circumstance. however. the user can assume that the larger
`of the two (K or N) is the dimensionality of the system. and
`some of the dimensions have either no digital data. or no
`analog data. whichever applies. Of course.
`if there are
`“dimensions" for which there is no digital or analog data.
`other information can be sent over those dimensions. such as
`equalization “side“ information.
`In the context of a signal space. the N pluralities of output
`signals of elements 50 and 60 (assuming N is larger than K)
`correspond to the collection of components of vectors in
`mold—dimensional space; e.g.. N-dimcnsional space. The
`coordinates of this multidimensional space correspond to
`the orthogonal modulation signals within orthogonal modu-
`lator 90. In FIG. 6. the two orthogonal modulation signals
`are cos to t and sin or t. but other modulation signals are also
`possible; for example. code division multiplexing {CDMM
`templates. For purposes of this disclosure. orthogonal modu—
`lation signals are modulation signals that develop a trans—
`mitted signal comprising concurrent element signals and yet
`allow the receiver to separate the received signal into its
`constituent element signals. those being the signals develv
`oped in response to each of the modulation signals. It may
`also be observed that. relative to FIG. 5. orthogonal modu—
`lator 90 performs vector summation of the symbol vector
`represented by the components developed by element 60
`with the analog information vector represented by the com—
`ponents developed by element 50. This is depicted in FIG.
`7.
`
`

`

`5.531436
`
`7
`In connection with FIG. 1, it may be noted in passing that
`the principles disclosed herein may be utilized even when
`the output signals of adders 7|] and 80 are communicated
`(cg. transmitted) directly. without the benefit ol combining
`them in orthogonal modulator 90. Also. orthogonal modu—
`lator 90 can simply be a bandshifting means. To the extent
`that the output of adder 70 (for example} is band-limited, the
`output of adder 80 can be shifted beyond the band-limited
`output signal of adder 70 and combined with the output
`signal of adder 70. This is presented in FIG. 8. It may also
`be appreciated that the principles disclosed herein may be
`exercised without the use of element 6|) in those situations
`where no digital streams are presented.
`To this point in the instant disclosure, the implication has
`been that the input signal applied to element 50 of FIG. 6 is
`analog. However, that does not have to be strictly the case.
`In accordance with conventional techniques, an analog sig—
`nal that is bandlimited can be sampled (within the proper
`Nyquist bounds). Hence. it should be understood that the
`input signal
`to element 50 can be a sequence of analog
`samples. Moreover. a sampled analog signal can be quan-
`tized and represented in digital form. Indeed. an analog
`signal that has been sampled and converted to digital form
`can then be converted to amplitude quantized pulse ampli-
`tude—modulated format; e.g., conventional PCM. All of
`those representations are representations ofan analog signal.
`For example. the collection of the amplitudcnquantizcd PAM
`pulses is identical to the original analog signal within the
`bounds of the quantization errors introduced by the sampling
`and quantizing (AID conversion followed by 01A conver-
`sion) processes.
`The fact that sampling and amplitude quantization of the
`analog signal at the input of element 50 is pcmtitted ofi'crs
`a number of benefits. For one. it allows the signal
`to be
`presented to element 50 in digital format. For another. it
`permits
`simple multiplexing
`of different
`information
`sources. Thus. for example, elements 50, 6|] and 90 can be
`implemented in accordance with present day modern real-
`izations; i.e.. with one or more microprocessors operating
`under stored program control.
`An example of input signal multiplexing is shown in FIG.
`9, which presents an embodiment
`that includes an AID
`converter bank 30 followed by a multiplexer 40. Converter
`bank 30 converts a plurality of analog signals, such as on
`lines 33 and 34.
`to digital format and multiplexer 40
`multiplexes its input signals and applies them to element 50.
`Elements 30 and 40 are conventional AID and multiplexer
`elements. respectively.
`The combination of elements 30 and 4|] allows applying
`a number of narrowband analog signals to orthogonal modu-
`lator 90. The primary limitations are the carrier frequency
`and the allowable transmission bandwidth of the channel.
`The narrowband signal can. of course, come from any
`source. For example. a system installed in an ambulance
`may sacrifice some voice bandwidth in order to allow
`narrowband telemetry data of blood pressure and heart pulse
`rate to be communicated concurrently with the voice.
`Additionally. a voice signal energy detector may be
`included. such as disclosed in U.S. Pat. No. 5.081.647.
`which would detect periods of silence and send less urgent
`telemetry data during those silence periods. The silence
`periods may be naturally occurring periods. or silence peri-
`ods enforced for the purpose of commurticating telemetry
`information. such as data about the analog information just
`sent or about to be sent. This is illustrated by elements 31
`and 32 in FIG. 9.
`
`I0
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`The fact that the input to element 50 is digital (in a digital
`implementation of elements 50. 60 and 90} and that the input
`to element 60 is also digital should not be confused. The
`digital input to element 60 is a stream of digits that are each
`equally important. Henee, those digits are convened into
`symbols and the symbols into constellation points. and the
`constellation points are within neighborhoods which are
`identified by a slicer (cg. slicer 220 in FIG. 1] within a
`modem's receiver section. In contradistinction. the digital
`signals applied to element 50 correspond to digital words
`that represent amplitude, and the specific inten'elationship
`between adjacent bits of the digital words is maintained. As
`indicated above. being a fundamental distinction. the signal
`cloud around a signal point within a constellation does not
`represent a plurality of signal points that must be distin-
`guished.
`FIG. 10 presents a basic block diagram of a modcm's
`receiver section in conformance with the principles dis-
`closed herein. The modulated input signal received from the
`channel is applied to demodulator 210 which develops the
`in—phasc and quadrature components. Those are applied to
`slicer 220 which identifies the symbols, and the symbols are
`applied to tie-mapper 230. All this is in accord with corn
`ventlonal modern approaches. as described in connection
`with FIG. 1. In addition, FIG. 10 includes a mapper 240 that
`is responsive to the symbols developed by slicer 220. The
`output of mapper 240 is an accurate estimate of the set of
`in~phase and quadrature components (that are applied in the
`FIG. I arrangement to elements 150 and 160). The outputs
`of mapper 240 are subtracted from the outputs of demodu-
`lator 210 in subtractors 250 and 260. The outputs of sub-
`tractors 250 and 260 are applied to 2~to—l dc-mapper 270
`which recombines the analog samples to form an estimate of
`the original analog signal. Dc-mappcr 2T0 performs the
`inverse function of mapper 50.
`In may be noted that slicer 220 can be designed to directly
`provide the output signals that mapper 240 develops; and
`moreover, de-mapper 230 can be made responsive to such
`signals. That would alter the FIG. 10 in the sense that slicer
`220 and mapper 240 would combine to form a single
`element and tie-mapper 230 as well as adders 250 and 260
`would be responsive to that combined element.
`In analog realizations (c.g.. FIG. 6]. mappchO is respon—
`sivc to analog signals. Various approaches can be taken to
`develop the plurality of outputs [two outputs. in the ease of
`element 50 shown in the FIGS.) For example. a single
`bandlirnited analog signal can be divided into a plurality of
`baseband signals by simply filtering and modulating
`selected sub-bands. Alternatively. element Si] can accept a
`plurality of bandlimited analog signals and assign each one
`of the plurality of bandlimited analog signals to different
`outputs of element 50.
`In time sampled realizations [whether the realization
`continues with analog circuitry or digital circuitry). element
`5|] can simply route alternate samples of a single analog
`signal
`to different outpu