EP0876725A1 - Codage de donnees numeriques en une forme d'onde analogique a diagramme d'interference a niveaux et a frequences multiples pour transmission - Google Patents

Codage de donnees numeriques en une forme d'onde analogique a diagramme d'interference a niveaux et a frequences multiples pour transmission

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Publication number
EP0876725A1
EP0876725A1 EP97903777A EP97903777A EP0876725A1 EP 0876725 A1 EP0876725 A1 EP 0876725A1 EP 97903777 A EP97903777 A EP 97903777A EP 97903777 A EP97903777 A EP 97903777A EP 0876725 A1 EP0876725 A1 EP 0876725A1
Authority
EP
European Patent Office
Prior art keywords
analog waveform
waves
symbol
waveform
input data
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97903777A
Other languages
German (de)
English (en)
Inventor
William A. Ganter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Transcendata Inc
Original Assignee
Transcendata Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Transcendata Inc filed Critical Transcendata Inc
Publication of EP0876725A1 publication Critical patent/EP0876725A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems

Definitions

  • the present invention relates to a data encoding method and apparatus capable of encoding digital data into a smooth analog waveform.
  • Fig. 1 illustrates the pulse code modulation (PCM) in a 100 Mbps Ethernet wire LAN, defined within the IEEE Standard 802 series.
  • PCM pulse code modulation
  • Fig. 1 illustrates the pulse code modulation (PCM) in a 100 Mbps Ethernet wire LAN, defined within the IEEE Standard 802 series.
  • PCM is widely used in connecting distributed computers to servers and in other computer networks, such as Intranets.
  • this technology is limited by specification to 328 feet of propagation.
  • the voltage state changes produce many unwanted frequencies that interfere with the data transmission and complicate data detection by a detector. For example, a voltage swing of one volt within a few nanoseconds results in the ringing shown in Fig. 1.
  • a plurality of N selected sinusoidal waves of N frequencies be set to particular gain levels and particular phase shifts to form a code set. (symbol) .
  • the code set is detected by a detector which performs a discrete Fourier transform (DFT) computation on the detected symbol at each of the N frequencies to recover each of the N gain and N phase shift settings that were in effect during that symbol interval .
  • DFT discrete Fourier transform
  • Each of the N waves is treated as a separate subcarrier and the bandwidth spans the full range of the N frequencies used. Due to the computational complexity and discontinuities of N waves at each symbol boundary, the symbol must be held for a sufficiently long symbol duration (interval) for the detector to identify and decode the received symbol. However, such long symbol interval leads to low data transmission rates and may explain why this method is not utilized in currently available data transmission devices.
  • Another object of this invention to provide an encoding method and apparatus which controls the frequency content of the waveform that is used to transmit the encoded data.
  • a further object of this invention is to provide an apparatus and technique as aforesaid, wherein the AC analog waveform that transmits the encoded data is within a narrow bandwidth such that it can be bandpass filtered to remove out-of-band noise, thereby enabling independent transmission channels to be closely spaced for efficient spectrum utilization.
  • An additional object of this invention is to provide an apparatus and technique as aforesaid for encoding data with a high encoding efficiency.
  • an encoding method for encoding input data into a plurality of analog waves which are combined to produce a unique interference pattern representing the input data.
  • a plurality of analog waves of selected frequencies is generated, each exhibiting a phase- and gain-controlled in accordance with the input data.
  • the phase- and gain-controlled waves are combined to create a unique interference pattern that appears as a single AC analog waveform.
  • the input data is divided into data segments of N-bits and the N-bit data segment is encoded into a plurality of phase- and gain-controlled analog waves .
  • encoding and decoding apparatus are incorporated in transmitter and receiver, respectively, to permit communication of information across large distances. Also, the encoding and decoding apparatus may be incorporated in a regenerative repeater to assist in the transmission of information without deterioration.
  • Fig. 1 is an actual A/D sampling of a 100 Mbps Ethernet transmission
  • Fig. 2 is an actual A/D sampling of a 200 KHz waveform transmission of the present invention
  • Fig. 4 is an actual A/D sampling of the symbol waveforms s(t) generated and transmitted by another embodiment of the present invention,-
  • Fig. 5 is an actual A/D sampling of the symbol waveforms s(t) generated and transmitted by yet another embodiment of the present invention.
  • Fig. 6 is an actual A/D sampling of the symbol waveforms s(t) generated and transmitted by still another embodiment of the present invention,-
  • Fig. 7 is an actual A/D sampling of the symbol waveforms s(t) generated and transmitted by still yet another embodiment of the present invention
  • Fig. 8 is a block diagram illustrating an embodiment of the encoding apparatus of the present inven ion;
  • Fig. 9 is a block diagram illustrating another embodiment of the encoding apparatus of the present invention,-
  • Fig. 10 is a block diagram showing W separate frequency synthesizers incorporated in the encoding apparatus of Fig. 9,- and
  • Fig. 11 is a block diagram of the generalized A/D sampling and signal processing apparatus of the present invention, for detection and decoding of the received AC analog waveform.
  • the transmission apparatus of the present invention propagates a smooth analog AC waveform directly in either wire or air, or alternatively this waveform modulates a carrier wave which is then propagated.
  • the waveform is made up of a sequence of symbols that are seamed together at the symbol boundaries.
  • the voltage level of the waveform at the symbol boundaries is zero so that symbols can be seamed together without significant discontinuity.
  • Fig. 2 shows a smooth AC analog waveform in accordance with this invention having a frequency of 200 KHz .
  • Waveforms in accordance with this invention can propagate several thousands of feet in wire, supporting data rates of several hundred Mbps. Its data rates are limited only by the maximum clock rates of present integrated circuit (IC) technology, rather than by noise.
  • IC integrated circuit
  • the AC analog waveform in accordance with this invention may modulate an RF carrier wave.
  • the AC analog waveform generated in accordance with this invention offers a high spectral utilization resulting from closely spaced non-interfering carrier waves or from closely spaced non-interfering directly propagating waveforms.
  • the carrier-to-noise ratio of this invention in order to support a given bit error rate, is very favorable due to its narrow bandwidth, which allows out-of-band noise to be filtered out.
  • Each symbol encodes N bits of digital data.
  • variables needed to code and generate the symbol waveforms, and needed to detect and decode these symbol waveforms, are computed.
  • these computed variables are designed into the custom integrated circuits (IC' ⁇ ) that implement the transmission technology of the present invention.
  • the variables are optimized, through the computation discussed below, for its particular operating environment.
  • multiple combinations of the variables are available, but the optimal selection of these variables may be limited by a series of tradeoffs, such as cost and various performance requirements of that particular application.
  • Each symbol spans predetermined timing intervals, referred to as cells, where each cell represents a predetermined time duration L seconds.
  • the polarity of the AC analog waveform which represents the symbols alternates by cell, that is, it is opposite in adjacent cells.
  • t ranges from 0 to KL seconds (defining the outer boundaries of a symbol)
  • K is equal to the span or number of cells
  • g ⁇ and p ⁇ denote the gain and phase of the x wave.
  • the frequency of the x wave is given by f x/2KL Hz.
  • the gain and/or phase of each wave are controlled so that the signal level of the symbol waveform s(t) is substantially zero at all of the symbol boundaries.
  • equation (1) reduces to the following:
  • Fig. 3 illustrates two symbol waveforms s(t) representing two symbols seamed together to form an AC analog waveform.
  • M--16 unique interference patterns can be generated, in this example, with each of the 16 interference patterns representing a unique symbol.
  • N the maximum number of data bits that can be encoded per symbol
  • the number of constraints i.e., C ⁇ and C 2 , is shown to be equal to two per cell, it is appreciated that the number of constraints per cell can be any number greater than or equal to one.
  • Fig. 4 is a received AC analog waveform formed from five symbol waveforms s(t) representing five successive symbols.
  • Each symbol waveform is the interference pattern formed from three sinusoidal waves having a narrow band of frequencies f 1 8 , f 2 and f 2.
  • f 1 8 , f 2 and f 2 frequencies f 1 8 , f 2 and f 2.
  • f 1 8 , f 2 and f 2 frequencies f 1 8 , f 2 and f 2.
  • K 2 cell span
  • g ⁇ represents the gain of a constituent wave having frequency f ⁇ .
  • s 5 (t) - ⁇ 5 sin(1.667 ⁇ t+p 5 ⁇ )
  • s (t) s (t) +s 3 (t) +s E (t) .
  • the amplitude of the symbol waveform s(t) at the interior cell boundaries are not constrained to zero and are not necessarily at the zero voltage level.
  • the shape of the AC analog waveform can be more precisely controlled and two readings of C ⁇ , C 2 and C 3 can be provided to reduce the effects of noise.
  • An example describing a technique for increasing the number M of symbols by controlling, i.e., tilting, the waveform shape within each cell is described later.
  • equation (17) cannot be used to solve for the five wave variables, g -g s .
  • the remaining solutions for g ⁇ , g 3 and g 5 can be derived by adding s(.25L) to s(2.75L), adding s(.75L) to s(2.25L) and adding s(1.25L) to s(1.75L) :
  • Fig. 7 is the received analog waveform representing the same three symbols as in Fig.
  • Tilting the symbol waveform s(t) with the dependent wave advantageously increases the number of encoded bits per symbol from 8 to 10.
  • the number of arbitrarily chosen dependent waves that can be added is not limited to one, but any practical number greater than or equal to one can be added so long as the symbol boundary conditions are met, the number of independent equations is not increased and the detector is able to recognize the additional interference patterns. For example, if another dependent in-phase wave having frequency f is added to the aforementioned example, the number of unique symbols can be further increased.
  • the system may dynamically adjust the value of M (the number of unique symbols) in response to the condition of the transmission channel, i.e., use the reduced set of symbols for a noisy channel and the full set of symbols for a "clean" channel.
  • the data (transmission) rate may be initially set to the highest error-free rate and lowered when the error count exceeds a predetermined threshold, i.e., the data rate can be lowered by setting g 9 to zero and further lowered by setting both g g and g 6 to zero. It is appreciated that the system may dynamically adjust the value of M in response to other conditions, such as an overload detector.
  • the additional dependent waves can be used to reduce the amplitude requirements of W sinusoidal waves to create an unique interference pattern.
  • the amplitude of the symbol waveform s(t) at the center of two exterior cells (first and fifth cells) of each symbol can be constrained to one predetermined voltage level, such as the average amplitude, but the three interior cells (second, third and fourth cells) of each symbol may have a total of M combinations of constrained amplitudes.
  • the data bits are coded into only the three interior cells of each symbol and the exterior cells (first and fifth cells) contain no coded data and may be treated as overhead.
  • the non-coding of the exterior cells enables a detector to recognize individual symbols easier and minimizes the narrow bandpass filter memory effects by partially decoupling the sequence of symbols.
  • the non-coding overhead can be avoided by spreading the filter cutoffs until the narrow bandpass filter memory effects are minimized.
  • Fig. 8 there is illustrated a block diagram of one embodiment of the encoding apparatus of the present invention.
  • the encoding apparatus of Fig. 8 is preferably implemented as an integrated circuit and is comprised of a data buffer 210, a controller 220, a local oscillator 230, a frequency synthesizer and shaper 240, phase shifters 250A and 250B, gain amplifiers 260A and 260B, and combiners 270A and 270B.
  • the wave variables g ⁇ and p ⁇ for each of the constituent waves, manner discussed above, are stored in the gate logic of controller 220.
  • the oscillator 230 generates a clock signal, which is supplied to the frequency synthesizer and shaper 240 for generating a predetermined number W (W>1) of the aforementioned substantially pure sinusoidal waves of selected frequencies. These waves (W is an integer) are coupled alternately to the phase shifters 250A and 250B. It is appreciated that a set of W waves of different frequencies is generated with the lowest frequency wave being thought of as the first wave in the set (wave labeled as g_sin(.5t ⁇ ) in Fig.
  • a single reference wave may be generated, from which the remaining constituent waves may be synthesized by appropriate frequency division and frequency multiplication.
  • it may be more convenient to generate W waves using W separate frequency synthesizers and shapers.
  • Input data such as the serialized bits of digital information
  • the data buffer 210 which divides the input data into data segments of N-bits wherein N represents an integer greater than or equal to one.
  • Successive data segments are supplied to the controller 220 which generates, as a function of the N- bit data segment, a predetermined number of phase shifts (p ⁇ 's) and a predetermined number of gains (g ⁇ 's) .
  • a respective phase shift p ⁇ and a respective gain g ⁇ correspond to each wave generated by the frequency synthesizer and shaper 240.
  • the phase shifts are supplied alternately to the phase shifters 250A and 250B, and the gains are supplied alternately to the gain amplifiers 260A and 260B.
  • phase shifters 250A and 250B control the phase of each wave received from the frequency synthesizer and shaper 240 in accordance with the corresponding phase shift (p ⁇ ) received from the controller 220.
  • the phase controlled waves are then supplied from the phase shifters to the gain amplifiers 260A and 260B, respectively.
  • Each gain amplifier is uniquely associated with a particular phase shifter.
  • the gain amplifiers 260A and 260B control the amplitude of each phase controlled wave received from the respective phase shifters 250A and 250B in accordance with the corresponding gain (gj supplied thereto from the controller 220.
  • the gain and phase controlled waves are then coupled to the combiners 270A and 270B, and each combiner is uniquely associated with a particular gain amplifier.
  • Each of the combiners 270A and 270B combines gain- and phase-controlled waves to create an interference pattern that is formed as a symbol waveform s(t) representing a unique symbol, such as shown in Fig. 3.
  • N-bits of data are encoded as a unique interference pattern, or symbol, depending upon the value of those N-bits.
  • Each combiner may comprise a digital signal processor to enhance the processing of the combined waves.
  • the symbol waveform s(t) is then supplied to the output unit 80 for transmission.
  • the output unit 80 seamlessly combines the symbol waveforms s(t) representing successive N-bit data segments to create a single AC analog waveform for transmission. It is recalled that this advantageously results because of the symbol boundary condition, i.e., zero voltage level. Pairs of phase shifters, gain amplifiers, and combiners enable the apparatus to prepare the next N-bit data segment while transmitting the current data segment. For example, the circuits of what may be thought of as channel A may function to transmit the current data segment while the circuits of channel B function to prepare the next data segment.
  • a switch 90 connects the output unit 80 either to combiner 270A or 270B depending upon which combiner is processing the current data segment.
  • the number of channels of phase shifters, gain amplifiers, and combiners is not limited to two and can be any practical number greater than two as long as these additions improve the symbol set upon implementation by allowing additional symbol set-up time.
  • Fig. 9 there is shown a block diagram of one section of the encoding apparatus of Fig. 8. Each section comprises phase shifters 250A ⁇ -250A w and corresponding W gain amplifiers 260A ⁇ -260A w .
  • the oscillator 230 supplies the clock signal to each of the frequency synthesizer and shapers 240 ⁇ 240 ⁇ Each frequency synthesizer and shaper generates one of the W waves (see Figs. 3-7) to be superimposed to create the symbol waveform s(t); i.e., the frequency synthesizer and shaper 240: generates the wave x out of , which is supplied to the phase shifter 250A ⁇ (see Fig. 3) .
  • Each one of the p r hase shifters 250AI-250AW controls the phase of a respective one of the W waves received from the frequency synthesizer and shaper 240 - 240 w with the corresponding phase shift; i.e., p ⁇ controls the phase of the wave x of the first set of W waves.
  • the W phase controlled waves in the set are then supplied to the gain amplifiers 260 ⁇ -260 w . That is, the phase shifter 250A controls the phase of the wave x with the corresponding phase shift p ⁇ and supplies the phase controlled wave x to the gain amplifier 260A ⁇ .
  • Each one of the W gain amplifiers 260A ⁇ -260A w controls the gain (amplitude) of a respective one of the phase controlled waves with the gain corresponding thereto; and the W phase and gain controlled waves in a set are supplied to the combiner 270A.
  • the gain shifter controls the amplitude of the phase controlled wave x with the corresponding gain g and supplies the phase and gain controlled wave x to the combiner 270A.
  • FIG. 10 there is illustrated a block diagram of another embodiment of the apparatus for encoding and generating a sequence of symbol waveforms s(t) for transmission.
  • the apparatus is comprised of a data buffer 110, an address generator 120, an electronic memory table 130, a D/A converter 140, a low pass filter 150 and an output unit 80.
  • Input data such as serialized bits of digital information, is supplied to the data buffer 110 which divides the input data into data segments of N-bits wherein N represents an integer greater than or equal to one. Successive N-bit data segments are read from the data buffer 110 by the address generator 120.
  • the address generator 120 generates a code or address, corresponding to each N-bit data segment to uniquely identify a previously recorded (stored) symbol waveform s(t) out of the possible M previously recorded symbol waveforms s(t) .
  • the address is supplied to the table 130.
  • Table 130 has electronically stored therein the sample digital output values (levels) associated with each of the M unique symbol waveforms s(t) in a respective table. For example, there are M addressable tables to record the sample amplitude levels for each of the M symbol waveforms s(t) . In one embodiment, these sample amplitude levels were previously obtained by sampling each of the M unique symbol waveforms at P equally spaced intervals per cell.
  • the table 130 uses the address received from the address generator 120 to uniquely address (identify) a respective table from which the sequence of output values representing the symbol waveform s(t) is supplied to the D/A converter 140.
  • Figs. 2 and 4-7 represent the symbol waveforms s(t) actually generated and transmitted by the encoding apparatus of Fig. 10 using D/A converter 140 with 12 bit output resolution, i.e., there are 4096 distinct output levels available.
  • the digital output value 2047 was set at the DC reference 0 volts.
  • the digital output values 0 and 4094 were adjusted to -400 mV and 400 mV, respectively, as a full scale.
  • Fig. 5 shows two symbol waveforms s(t) seamed together to form an AC analog waveform,- the first and second symbol waveforms were generated using tables 3.1 and 3.2, respectively. That is the output sequence 1-24 in table 3.1 was used to generate the first symbol waveform s(t) in Fig. 5 and the output sequence 25-48 was used to generate the second symbol waveform s(t) in Fig. 5.
  • the D/A converter 140 holds each received digital output level for L/P seconds and then outputs the next digital output level in the received sequence from table 130.
  • the low pass filter 150 smoothes these D/A output steps into the smooth AC analog waveform, such as in Figs. 4-7, and supplies the AC analog waveform to the output unit 80 for transmission.
  • the D/A converter produces a compound output wave analogous to that of CD music.
  • the AC analog waveform s(t) of this invention is much less musically rich as it produces usually a single varying amplitude tone of frequency 1/2L Hz.
  • the actual AC analog waveform generated and transmitted by the encoding apparatus of Fig. 10 and sampled by the digital oscilloscope are shown as the received waveforms in Figs. 4-7.
  • the digital oscilloscope determines (senses) the average frequency of the resulting AC analog waveform based upon the zero crossings of the waveform, which are approximately 500 KHz, 600 KHz, 450 KHz and 450 KHz, respectively, the f ⁇ frequencies of the aforementioned examples.
  • a spectrum analyzer instrument measuring these AC analog waveforms shows a spike at frequency f ⁇ , and nowhere else. This spectrum analyzer result supports the non-interference advantage of this invention.
  • the PCM waveform in Fig. 1, and all other pulse codes display many frequencies on a spectrum analyzer.
  • a fast Fourier transform (FFT) computation across the AC analog waveform of many seamed symbols of this invention typically only shows frequency component f ⁇ above the noise .
  • the W constituent frequencies are averaged to near zero power across many seamed symbols.
  • the detecting apparatus is preferably implemented as a custom integrated circuit and is comprised of a bandpass filter 310, an A/D sampler data buffer 320, a signal processor 330 and a decoder/memory 340.
  • the input AC analog waveform with the symbols (interference patterns) seamed together as depicted in Figs. 3-7 is supplied to the bandpass filter 310 which filters out the undesirable frequency range, i.e., frequencies sufficiently outside of the range of the W waves used to create the AC analog waveform.
  • the AC analog waveform within the pass band is then supplied to the A/D sampler data buffer 320 which samples the filtered AC analog waveform at predetermined spaced intervals. This sampled waveform contains systematic transmission effects, which alters the generated waveform.
  • the A/D sampler data buffer 320 preferably includes an internal clock for generating sampling pulses at these predetermined spaced intervals,- and the sampled values (or voltage readings) are supplied to the signal processor 330.
  • the signal processor 330 must take into account the systematic transmission effects, including the effects of the bandpass filter 310 and the low pass filter 150 in Fig. 10.
  • the signal processor may be implemented with analog comparison circuitry, but for longer cell durations, a digital signal processor (DSP) utilizing conventional processing techniques and combinations hereof, such as integration, differentiation, threshold detection, and general pattern recognition, is preferable.
  • DSP digital signal processor
  • microcode improvements and updates may be readily implemented to overcome potential detector performance problems that were not previously considered or apparent in selecting (designing) the detector.
  • the signal processor 330 utilizing conventional processing techniques, processes the samples to determine the sequence of constrained output levels from C , C,, C and so forth used in generating the AC analog waveform stored in decoder/memory 340 (analogous to the sequence of output levels stored in the Table 130 in Fig. 10, i.e. Tables 3.1 and 3.2) .
  • the function of the signal processor 330 is to correctly recognize the sequence of symbols making up the transmitted AC analog waveform.
  • the recognized sequence of output levels is supplied to the decoder/memory 340.
  • the decoder/memory 340 decodes a recognized sequence of symbols received from the signal processor 330. If the received symbol is a data symbol, the decoder/memory 340 recovers the N-bits of data therefrom. On the other hand, if the received symbols corresponds to an extra symbol x, control action that may be represented by such extra symbol x is recovered. Some extra symbols may be used to control synchronization, addressing protocol, error detection, scrambling and compaction, among others.
  • the integrated circuits (ICs) of the generating and detecting apparatus of this invention are a matched pair of IC chips that contain the results of the design process.
  • the generating and detecting apparatus may be constructed as conventional microprocessors, preferably high-speed microprocessors.
  • the above-mentioned encoding and decoding apparatuses may be incorporated into an optical transmission system, such as a fiber optic system, a laser communication system, or the like.
  • the output unit 80 (Figs. 8 and 10) supplies the AC analog waveform representing a symbol to an optical intensity modulator which modulates the photon output of a light wave.
  • the encoding apparatus may be incorporated into an RF transmitter so that the AC analog waveform modulates a carrier wave resulting in an AM modulated waveform.
  • the RF carrier frequency thus modulated is assumed to be significantly higher than the frequency f ⁇ . It is recognized that the symbol waveform, that is, the AC analog waveform representing a sequence of symbols, amplitude modulates the RF carrier frequency.
  • the encoding apparatus may be incorporated into a magnetic storage device, wherein the AC analog waveform from the output unit 80 (Figs. 8 and 10) is used to modulate the write current of a recording head so as to induce flux changes in the magnetic media of a magnetic recorder.
  • the read head of the magnetic storage device provides the analog waveform input to the bandpass filter 310 of the decoder (Fig. 11) .
  • the encoder and decoder are provided at each end of a two-way transmission system.
  • the two-way transmission system may operate with a single channel by utilizing reverse signalling.
  • Two-way systems may also operate with separate channels, with a respective channel being assigned to a particular transmission direction.
  • the encoder and the decoder are incorporated into a regenerative repeater.
  • the AC analog waveform s(t) received by the repeater is decoded into data by the decoder; and the encoder re-encodes that decoded data into another AC analog waveform s' (t) that is re ⁇ transmitted.
  • the repeater may encode the data differently from the form in which it is received to provide added security, i.e., different embodiments of the encoder are incorporated into the transmitter and the repeater, respectively.
  • the analog waveform generated by the repeater s' (t) may differ from the received analog waveform s(t) .

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Dc Digital Transmission (AREA)

Abstract

L'invention se rapporte à un système qui consiste à coder des donées numériques en une série de formes d'onde analogiques, appelées formes d'onde de symboles résultant de l'interférence de diagrammes d'interférence d'ondes sinusoïdales. Chacune de ces formes d'onde constitue une version codée de N-bits de données (case 210). Ces formes d'onde de symboles codés représentent une version codée très différente, tant en apparence qu'en ce qui concerne leurs propriétés de propagation, des codes de signalisation d'état de la tension ou des codes d'impulsions. Les formes d'ondes de symboles codés sont formées par la création (cases 230 et 240) et la superposition (cases 270A et 270B) d'un ensemble d'ondes sinusoïdales analogiques, dans lequel le gain (cases 260A et 260B) et le décalage de phase (cases 250A et 250B) de chaque onde sont calculés de façon à fournir, par combinaison, un diagramme d'interférence unique qu'un détecteur peut reconnaître par des techniques de traitement des signaux, pour ensuite le décoder. Les formes d'onde de symboles sont calculés de telle sorte que les formes d'onde de symboles successifs se combinent ensemble pour former un signal analogique AC continu lisse présentant les caractéristiques suivantes: il ne crée pas, en tant que tel, de fréquences de brouillage; il peut être filtré par filtre passe-bande et convient à une propagation longue distance. La technique de transmission faisant l'objet de la présente invention s'applique, entre autres, à un dispositif ou à un système de communication numérique.
EP97903777A 1996-01-16 1997-01-10 Codage de donnees numeriques en une forme d'onde analogique a diagramme d'interference a niveaux et a frequences multiples pour transmission Withdrawn EP0876725A1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US984396P 1996-01-16 1996-01-16
US9843P 1996-01-16
US77352797A 1997-01-01 1997-01-01
PCT/US1997/000397 WO1997026745A1 (fr) 1996-01-16 1997-01-10 Codage de donnees numeriques en une forme d'onde analogique a diagramme d'interference a niveaux et a frequences multiples pour transmission
2003-12-03

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US11876659B2 (en) 2017-10-27 2024-01-16 Terawave, Llc Communication system using shape-shifted sinusoidal waveforms

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US4058805A (en) * 1975-06-16 1977-11-15 Comdial Corporation Digital multitone generator for telephone dialing
US4349704A (en) * 1979-12-31 1982-09-14 Bell Telephone Laboratories, Incorporated Digital multifrequency signal generator
EP0147791B1 (fr) * 1983-12-26 1990-08-29 Kabushiki Kaisha Toshiba Générateur de signaux DTMF
US4563548A (en) * 1984-04-10 1986-01-07 Advanced Micro Devices, Inc. Method and circuit for telephone dialing signal generation
GB2177862B (en) * 1985-07-09 1989-07-19 Motorola Inc Waveform generators
US5588053A (en) * 1995-11-29 1996-12-24 Advanced Micro Devices DTMF detector system and method which performs static and dynamic thresholding

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