EP1844544A2 - Demodulateur et modulateur-demodulateur par conversion directe de frequence - Google Patents
Demodulateur et modulateur-demodulateur par conversion directe de frequenceInfo
- Publication number
- EP1844544A2 EP1844544A2 EP05809116A EP05809116A EP1844544A2 EP 1844544 A2 EP1844544 A2 EP 1844544A2 EP 05809116 A EP05809116 A EP 05809116A EP 05809116 A EP05809116 A EP 05809116A EP 1844544 A2 EP1844544 A2 EP 1844544A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- input
- circuit
- demodulator
- signal
- modulator
- 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- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/16—Circuits
- H04B1/30—Circuits for homodyne or synchrodyne receivers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
- H03D7/12—Transference of modulation from one carrier to another, e.g. frequency-changing by means of semiconductor devices having more than two electrodes
- H03D7/125—Transference of modulation from one carrier to another, e.g. frequency-changing by means of semiconductor devices having more than two electrodes with field effect transistors
Definitions
- the present invention relates to the field of radio frequency applications, in particular that of radiocommunication with carrier frequency and transceivers by direct conversion of frequency.
- the invention more particularly relates to a demodulator and a modulator-demodulator adapted to be used in particular in such transceivers.
- Direct frequency conversion receivers - also known as homodynes - have become widespread today because of the simplicity of the circuits which makes it possible to limit the costs in comparison with heterodyne architectures. Its principle is based on the vector decomposition of the modulated signal received. Since the modulated signals received are completely characterized by their complex envelopes, a base defined by two orthogonal vectors - the so-called Cartesian base - is sufficient to represent them. However, it is very difficult to provide a two-way circuitry ensuring orthogonality between two signals in a high frequency range as used in broadband and / or multiple band systems.
- Direct frequency conversion receivers more suitable for broadband and / or multiple band systems are the five or six port receivers, see more, which provide from two inputs at least three output signals from which it can be estimated the Cartesian components of the complex envelope of the modulated signal received. These systems make it possible to overcome the orthogonality constraints of Cartesian receivers by means of a calibration procedure throughout the operating frequency band. Similarly, there are uplinks for direct conversion transmitters using two-way modulators carrying Cartesian base signals. Modulators based on three vectors have also been proposed.
- EP-A-0 805 561 discloses a six-port junction based demodulator, power detectors and an analog processing circuit for retrieving the I and Q Cartesian components of the complex envelope of the received signal.
- US-A-6,650,178 a direct conversion receiver with at least three ports. This circuit uses two passive interferometric circuits connected by a phase shifter element. The information carried by the received signal is recovered from the
- US-A-5,498,969 discloses a six-port junction architecture applied to a vector measurement device with a power divider circuit, a phase shifter circuit, a suitable power sensor and three other non-adapted.
- EP-A-0 841 756 discloses a six-port receiver using a correlator circuit in which the received modulated signal is summed with four signals from the reference oscillator, but out of phase with each other by 90 °.
- the values of the Cartesian components of the baseband signal are found by an analog circuit from the powers of the RF signals.
- US-A-5,095,536 discloses a direct conversion receiver based on a three-phase architecture and three mixer circuits.
- the reference signal is divided into three out of phase channels which are then mixed with the received modulated signal.
- the information is recovered by digital processing of the signals supplied to the filter and amplifier outputs placed after the mixers.
- the aim of the invention is to propose a new technology for demodulation, or even modulation and demodulation, by direct frequency conversion which is of a simple and economical implementation, which can notably be implemented at high frequencies such as as microwave but allow to be integrated more easily than existing technologies and that is capable of operating in wide frequency band if this is desirable.
- the present invention firstly proposes a vector addition device of two modulated or non-modulated alternating electrical signals, comprising:
- a first circuit connected to the first input and comprising a number n of outputs, the first circuit supplying, from the first alternating signal applied to the first input, a respective alternating signal on each of the n outputs, the said alternative signals supplied on the n outputs being all of the same amplitude and the same frequency but out of phase with each other so that each is neither in phase nor in phase opposition with any other;
- a second circuit connected to the second input and comprising the same number n of outputs, the second circuit dividing the second alternating signal towards its n outputs;
- the invention comprises one or more of the following features:
- each of the alternating signals supplied by the first circuit on its n outputs is out of phase with each of the other alternating signals supplied by the first circuit on its n outputs of 20 ° to 160 ° in advance or late;
- the summators each comprise two transistors mounted in a differential amplifier;
- the first circuit comprises the same number n of amplifiers, the input of each of the amplifiers being connected to the first input and the output of each of the amplifiers being then connected to a respective phase shift circuit.
- the number n is equal to 3
- each of the alternating signals supplied by the first circuit on its three outputs is out of phase with each of the other two alternative signals supplied by the first circuit on its three outputs by an angle of 80 ° to 160 ° in advance or late; each of the alternating signals supplied by the first circuit on its three outputs is out of phase with each of the other two alternative signals supplied by the first circuit on its three outputs by an angle of 120 ° in advance or late;
- each of the summers is connected to a respective power sensor.
- the invention also proposes a direct conversion demodulator, comprising:
- the invention also proposes an RF receiver, comprising:
- a demodulator according to the invention; a local oscillator connected to the first input of the vector addition device; - an RF receiving antenna; and
- the invention also proposes a direct conversion modulator-demodulator comprising a demodulator according to the invention and in which the modulator comprises:
- variable gain amplifiers the input of each amplifier being connected to a respective output of the first circuit of the vector addition device;
- the modulator-demodulator may advantageously comprise a circuit for selectively connecting the second input of the vector addition circuit to the output of the adder receiving as input the output of each of the n variable gain amplifiers.
- the invention also proposes a transceiver, comprising:
- a local oscillator connected to the first input of the vector addition device; and at least one RF antenna and at least one amplifier for supplying the second input of the vector addition device and for transmitting the signal obtained at the output of the summator connected to the n variable gain amplifiers.
- the invention also proposes a method of calibrating the modulator of a modulator-demodulator according to the invention at a given frequency, the demodulator having been previously calibrated at the given frequency, the method comprising the steps of: - application of a signal alternating with the frequency given at the first input of the vector addition device;
- the invention finally proposes a method of calibrating the demodulator of a modulator-demodulator according to the invention at a given frequency, the modulator having been previously calibrated at the given frequency, the method comprising the steps of:
- FIG. 1 is an illustration in the Fresnel plane of the electrical signals existing in a vectorial addition device according to the invention.
- FIG. 1 is a block diagram of a transceiver embodying the invention.
- FIG. 3 is an electronic diagram of a particular embodiment of a transceiver according to the invention.
- FIGS. 4 to 6 illustrate the results obtained with the circuit described with reference to FIG.
- the vector addition device of two alternative electrical signals comprises a first input for receiving a first AC electrical signal and a second input for receiving a second AC electrical signal. It comprises a first circuit connected to the first input and comprising a number n of outputs, the first circuit providing, from the first alternating signal applied to the first input, a respective alternating signal on each of the n outputs, said alternative signals provided on the n outputs being all of the same amplitude and the same frequency but out of phase with each other.
- These alternative signals provided on the n outputs are out of phase so that each is neither in phase nor in phase opposition with any other of them. In other words, in the Fresnel plane, none of the corresponding vectors is collinear with another of these vectors.
- the number n is greater than or equal to 3.
- It further comprises a second circuit connected to the second input and comprising the same number n of outputs, the second circuit dividing the second AC signal to its n outputs. Finally, it comprises the same number n of summers each receiving at input a respective output of the first circuit and a respective output of the second circuit.
- This device makes it possible, in particular, to supply several signals resulting from the sum of the same alternating signal with another alternating signal of the same frequency each time being out of phase at another angle, which then makes it possible to compare the two signals on the basis of the resulting signals. .
- the first signal provides a kind of vector base defined by n vectors, each of which is then added to the second signal.
- FIG. 1 illustrates this situation with the number n equal to 3, the reference 100 indicating the vector corresponding to the second signal, which is added several times to the first signal each time out of phase in this case by 120 ° and whose vectors are indicated by 101A, 101B and 101C.
- the resulting vectors of the sums are referenced 102A, 102B and 102C.
- Such an addition device advantageously makes it possible to compare two alternating signals of the same frequency both from the point of view of their phase and of their amplitude. For this, simply apply one to the first input of the device and the other to the second input of the device. In particular, the comparison can be
- the AC signals provided on the n outputs of the first circuit are each out of phase with all other of these signals by an angle in the range of 20 ° to 160 °, including terminals, regardless of whether either early or late.
- the direction of the vector corresponding to any one of these signals forms an angle of at least 20 ° with respect to the direction of the vector corresponding to any of these other signals. This makes it possible to obtain a sufficient sensitivity to make the comparison. From this point of view, it is advantageous to choose in the case where n equal to three a configuration for which each output signal of the first circuit is out of phase by + 120 ° and -120 ° with respect to the other two output signals.
- This device advantageously finds application when an incident signal is compared with a reflected signal to determine a reflection factor, for example in the analysis of electrical networks. Similarly, it finds application for the determination of transmission factor from an incident signal and the transmitted signal to implement a radar discriminator.
- This device also makes it possible to implement a demodulator by direct frequency conversion by applying the modulated signal to the second input and to the first input the signal of a local oscillator frequency-adjusted to that of the modulated signal.
- This is preferably digital modulation, but analog modulation is also possible.
- this is phase and / or amplitude modulation, but frequency modulation is also possible.
- the use of summators followed by quadratic detectors is advantageous over the use of mixers as in US-A-5,095,536 since the latter are more complex and more expensive.
- the third vector makes it possible to eliminate the ambiguity due to quadratic detection by
- the receiver portion of the transceiver comprises a D demodulator, a LO local oscillator and a modulated signal receiving antenna RFin.
- the demodulator D comprises a vector base generator 1, an RF signal splitter circuit 2, three RF signal summers 3a, 3b and 3c, three power sensors 4a, 4b and 4c, an analog conversion block. digital 5 and a digital processing circuit 6.
- the vector base generator 1, the RF signal divider circuit 2 and the three RF signal adder 3a, 3b and 3c constitute a vectorial adjuster as previously described.
- the demodulator D receives as input the modulated signal RFin and the alternating signal of a local oscillator LO which serves as a reference.
- the signal of the local oscillator LO is applied to the input of the vector base generator 1. From this signal, the vector base generator 1 outputs three alternating signals of the same frequency and of the same amplitude, but which are out of phase between they, each of the three signals being provided on a separate path. Each of the three channels is connected to an input of a respective summator 3a, 3b and 3c.
- the phase shift between the three signals can be obtained using passive or active filters, transmission lines or any other circuit providing a phase shift to a signal in the operating frequency interval of the demodulator.
- the modulated RFin signal is amplified by a low brait amplifier, not shown, before being applied to the divider circuit 2.
- the divider circuit 2 divides the modulated RFin signal into three distinct channels without introducing a phase difference between
- R ⁇ Brcvets ⁇ 22700 ⁇ 22719.doc - 8/22 they do not differ in amplitude.
- Each of these three paths is connected to the input of a respective summator 3a, 3b and 3c.
- the divider circuit 2 is represented symbolically in FIG. 1 by an input branch on which three branches each connected to an input of a respective summator 3a, 3b and 3c are connected.
- the divider circuit 2 can be implemented by placing the transistors in parallel with their matching and polarization circuits, which has the advantage of allowing the integration of the circuit and providing a wide band of operation by compared to classical structures based on propagation lines such as Wilkinson splitters.
- Each of the summers 3a, 3b and 3c thus provides at the output a signal corresponding to the addition of the signal provided by a respective channel of the vector base generator 1 and the RFin signal after division.
- the power of the output signal of each adder 3a, 3b and 3c is measured by a respective power sensor 4a, 4b and 4c which outputs an analog signal representative of the signal power.
- each power sensor 4a, 4b and 4c is implemented by a non-linear element such as a Schottky diode, followed by a low-pass filter to eliminate signal components other than those of the baseband.
- the analog signal supplied by each power sensor 4a, 4b and 4c is then converted into a digital signal by the analog / digital conversion unit 5, the digital signal being supplied to the digital processing circuit 6. Before digital conversion, this analog signal can optionally be conditioned by an adjustable gain amplifier circuit and / or a compensation circuit of the voltage or DC offset.
- the analog / digital conversion block 5 is implemented by a respective analog / digital converter for each power sensor 4a, 4b and 4c, with the sampling of these converters being simultaneous to ensure the coherence of the three measurement channels.
- the frequency of the local oscillator LO is set to that of the modulated signal RFin.
- the digital processing circuit 6 determines the Cartesian components of the complex envelope - referenced by Out (I, Q) in FIG. 1 - of the modulated signal RFin by digital processing of the signals representative of the powers measured by the power sensors 4a, 4b and 4c. In other words, the digital processing circuit 6 provides the demodulated signal.
- the digital processing circuit can conventionally comprise a microprocessor.
- the digital processing may be based on an appropriate algorithm and / or on a conversion table such as for example described by FR de Sousa, B. Huyart, SYC Catunda and RN de Lima in "A to D Converters and Look-up Tables Dimensioning". for Five-Port Reflectometer Based Systems "published in the Proceedings of the
- This digital processing is based on the transfer functions of the different channels of the demodulator, in particular the phase shifts and attenuations introduced by the vector base generator 1, the divider circuit 2 and the summers 3a, 3b and 3c, as well as the faults. linearity of the power sensors 4a, 4b and 4c. Moreover, these transfer functions generally vary according to the frequency with which the demodulator works.
- the parameters of the transfer function can be determined by a calibration procedure similar to those used in the prior art for five-port receivers or the like. For example, predetermined modulated signal sequences are sent by a base station to the transceiver which has previously stored the Cartesian components I and Q - respectively the real part and the imaginary part - corresponding to the complex envelope of these signals. After demodulation, the digital processing circuit 6 calculates the calibration constants so that the Cartesian components obtained by the demodulation are identical to those in memory, thus making it possible to calibrate the demodulator D as a function of the differences noted.
- the digital processing circuit 6 can further decode the demodulated signal before being restored in a conventional manner.
- VLO and ⁇ respectively the amplitude and the pulsation of the signal supplied by the local oscillator LO;
- the divider circuit 2 provides three signals each expressing: with:
- V RF (t), ⁇ (t) and ⁇ respectively the instantaneous amplitude, the instantaneous phase and the pulsation of the modulated signal RFm received at the input;
- n 3
- K, and KQ are dependent constants of the values of aj, bj, ⁇ , ⁇ ; and VLO
- the calibration procedure mentioned previously therefore consists of determining ai, ⁇ , Ki and KQ.
- these constants are expressed as a function of the parameters a ;, b; and ci from a matrix inversion of the system of three equations connecting the 3 measurement data v 3 '(t), v 4 ' (t) and v 5 '(t) to the three unknowns VRFCO 2 ' I (t) , Q (t) below:
- V 4 1 Ct) b 4 .
- VRF (0 2 + c 4 .cos ⁇ 4 I (t) + c 4 .sin ⁇ 4 Q (t) v 5 '(t) b 5.
- v 3 '(t) v 3 (t) - a 3 .V LO 2
- v 4 ' (t) v 4 (t) - a 4 .V LO 2
- v 5 '(t) v 5 (t) - a 5 .V LO 2
- the variables v 3 (t), v 4 (t), v 5 (t) are the analog output voltages of the power sensors.
- the transmitter part of the transceiver is based on a modulator M.
- the modulator M comprises a digital processing circuit which can be common with the demodulator D as shown in FIG. 1 by the circuit 6.
- D also comprises a block of digital-to-analog conversion 7 and three RF amplifiers with adjustable gain 8a, 8b and 8c and an RF signal summer 9.
- the modulator M furthermore comprises the vector base generator 1, which is therefore advantageously common with the demodulator D.
- Each of the three output channels of the VBG 1 is applied to the input D a respective amplifier 8a, 8b and 8c.
- each amplifier is controlled by a respective signal determined by the digital processing circuit 6 from the Cartesian components In (I, Q) of the coded signal to be modulated for its transmission.
- This digital processing is based on the transfer functions of each channel of the modulator, including phase shifts and attenuations introduced by the vector base generator 1 and the linearity defects of the amplifiers 8a, 8b and 8c.
- these transfer functions generally vary according to the frequency with which the modulator is working. It will be understood that the amplifiers 8a, 8b and 8c do not necessarily work at a gain greater than 1, but can work equally or exclusively at a gain less than 1, that is to say attenuator.
- the gain control signals determined by the digital processing circuit 6 are converted into analog signals by the digital-to-analog converter block 7 to each be applied to the control input of a respective amplifier 8a, 8b and 8c.
- the digital / analog conversion block 7 is implemented by a respective digital / analog converter for each amplifier 8a, 8b and 8c.
- each amplifier 8a, 8b and 8c is applied to a respective input of the adder 9. Therefore, the adder 9 outputs the modulated signal RFout which is the sum of the three signals provided by the amplifiers 8a, 8b and 8c.
- the output signal RFout of the modulator M is then conventionally amplified and applied to a transmitting antenna. Furthermore, the coding of the signal to be transmitted can be carried out by the digital processing circuit 6 prior to the determination of the gain control signals of the amplifiers 8a, 8b and 8c.
- Both the vector addition device according to the invention and the demodulator and the modulator-demodulator which incorporate it can be implemented to work at any frequency at which the receiver and the transceiver operate. They are particularly suitable for working at frequencies greater than or equal to 900MHz and can be used in broadband or multiband applications covering several gigahertz.
- the receiver and the transceiver according to the invention can work in different frequency bands by setting the frequency of the local oscillator to the desired frequency.
- transmission and reception can be at the same frequency or at different frequencies by changing the frequency of the local oscillator in correspondence.
- the invention provides a cost-effective time division duplex transceiver solution - abbreviated as TDD in English - since the vector base generator is common to the transmitting part and the receiving part. It is possible to implement a transceiver operating in frequency division duplex in - abbreviated as FDD in English - by adding a second vector base generator, one being specific to the demodulator and the other to the modulator.
- the transceiver may be subject to an automatic calibration of its modulator M after its demodulator D has been calibrated.
- the preliminary calibration of the demodulator D can be carried out in a conventional manner, in particular as described above.
- a controlled switch 20 - made for example by a transistor - makes it possible to selectively connect the output RFout of the modulator M to the input RFin of the demodulator D.
- the connection is shown in dashed lines in FIG. 2.
- the digital processing circuit 6 comprises in FIG. memory the Cartesian components of the complex envelope of a predetermined sequence of signals. To proceed with the calibration of the modulator M, the digital processing circuit 6 causes the switch 20 to close.
- R Brcvets ⁇ 22700 ⁇ 227I9 doc - 13/22 complex obtained by demodulation with the corresponding Cartesian components in memory used for modulation.
- the digital processing circuit 6 then calibrates the modulator M according to the differences observed during the comparisons. This calibration is made possible because the demodulator D has been previously calibrated and therefore the discrepancies observed during the comparisons come only from the error on the parameters of the modulator M in memory in the digital processing circuit 6.
- the transceiver can be subjected to an automatic calibration of its demodulator D after its modulator M has been calibrated in a conventional manner.
- FIG. 3 shows a simplified electronic transceiver diagram of FIG. 2 which has been implemented in MMIC technology (microwave monolithic integrated circuit) using the GaAs technology (ED02AH) of OMMIC.
- the vector base generator 1 has a three-way channel divider circuit realized by three amplifiers, the input of each of which is connected to the local oscillator LO.
- each amplifier is implemented in the form of a Tl transistor type FET 20 ⁇ m x 4. The fact of using an amplifier-based divider circuit makes it possible to maintain a constant response over a very wide band frequency.
- the transistors T1 are followed by respective phase-shifting circuits to provide the three output signals out of phase with each other.
- two all-pass filters and a fourth-order bandpass filter are used.
- the following values of the components provide a phase shift of 120 ° between two consecutive output channels of the vector base generator 1 in the frequency band 1.8-5.5 GHz: CIa: 0.16 pF Cb: 0.47 pF CIc : 0.31 pF
- the summers 3a, 3b and 3c as well as the power sensors 4a, 4b and 4c are made identically. For this reason, only the components of the summator 3a and the power sensor 4a are referenced in FIG.
- the summers 3a, 3b and 3c are each made by a pair of transistor T2 mounted as a differential amplifier.
- the transistors T2 are of the type
- the use of transistors provides the advantage of operating in a wide band of frequencies in comparison with the adder using transmission lines. In addition, they offer the choice of amplification, which can be an advantage when considering using the circuit with low power RF signals.
- the power sensors 4a, 4b and 4c each consist of a transistor T3, in this case of the FET type 10 ⁇ m ⁇ 1, with the channel close to the nip, which makes it operate in a very non-linear regime that approaches that of a Schottky diode.
- each low-pass filter comprises the resistors R1 and R2 and the capacitor C3 whose values are:
- each power sensor 4a, 4b and 4c delivers a respective output voltage Va, Vb and Vc which is then digitized by the analog / digital conversion block 5 - not shown in FIG. 3 - for the purpose of digital processing to provide the Cartesian components of the complex envelope of the RFin modulated signal.
- the modulated signal RFin is applied to the gates of three transistors of the summator 3a, 3, and 3c.
- the connection of their gates is possible because the isolation between drain and gate is very high, which makes it possible to consider the transistor as unidirectional.
- the matching circuit - not shown - takes into account the reflection factor of the three transistors to allow adaptation. Individually, each transistor works as an amplifier. In this way, the reference divider circuit 2 is obtained in FIG.
- variable gain amplifiers 8a, 8b and 8c of the modulator M are all identical, which is why only the components of the amplifier 8a are referenced in FIG. 3.
- Each amplifier comprises two transistors T4 and T5 mounted in cascode.
- the gain control voltages are symbolized by the generators 10a, 10b and 10c respectively.
- the transistors T4 are of the FET 25 ⁇ m ⁇ 4 type and the T5 transistors are of the 22.5 ⁇ m ⁇ 2 FET type.
- the fact of using cascode-type amplifiers 8a, 8b and 8c is advantageous because it suffices to connect together their outputs to realize the adder 9 given their great isolation.
- the transceiver comprises a switching block 11 which selectively allows to connect or isolate the RFout output of the modulator and the RFin input of the demodulator according to a control signal applied to the input 12. allows to implement the automatic calibration procedure of the
- FIGS. 4 to 6 illustrate the results obtained with the circuit described with reference to FIG.
- FIG. 4 shows the transmission coefficients of the three channels of the vector base generator 1.
- the coefficient module is between -7 dB and -17 dB in the band between 1.8 GHz and 5.5 GHz.
- the phase shift we obtain 120 ° relative between the three channels at about 3.5 GHz, and at the extremities the phase differences are about 80 ° and 160 °.
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR0410644A FR2876517B1 (fr) | 2004-10-08 | 2004-10-08 | Demodulateur et modulateur-demodulateur par conversion directe de frequence |
PCT/FR2005/002476 WO2006040453A2 (fr) | 2004-10-08 | 2005-10-07 | Demodulateur et modulateur-demodulateur par conversion directe de frequence |
Publications (1)
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EP1844544A2 true EP1844544A2 (fr) | 2007-10-17 |
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EP05809116A Withdrawn EP1844544A2 (fr) | 2004-10-08 | 2005-10-07 | Demodulateur et modulateur-demodulateur par conversion directe de frequence |
Country Status (4)
Country | Link |
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US (1) | US7890081B2 (fr) |
EP (1) | EP1844544A2 (fr) |
FR (1) | FR2876517B1 (fr) |
WO (1) | WO2006040453A2 (fr) |
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JP2011205283A (ja) * | 2010-03-25 | 2011-10-13 | Yamaha Corp | 信号処理装置 |
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EP1189338A1 (fr) * | 2000-09-06 | 2002-03-20 | Sony International (Europe) GmbH | Démodulateur I/Q à trois détecteurs de puissance et deux convertisseurs A/N |
JPWO2002091564A1 (ja) * | 2001-05-08 | 2004-08-26 | ソニー株式会社 | 復調器およびそれを用いた受信機 |
DE10122748A1 (de) * | 2001-05-10 | 2002-11-14 | Philips Corp Intellectual Pty | Anti-Demodulatorschaltung, Filtereinrichtung und Demodulatorschaltung |
US6765519B2 (en) * | 2002-12-23 | 2004-07-20 | Agilent Technologies, Inc. | System and method for designing and using analog circuits operating in the modulation domain |
KR100601939B1 (ko) * | 2004-01-16 | 2006-07-14 | 삼성전자주식회사 | Ofdm 시스템에서의 초기 주파수 동기 방법 및 장치 |
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2004
- 2004-10-08 FR FR0410644A patent/FR2876517B1/fr not_active Expired - Fee Related
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2005
- 2005-10-07 US US11/576,844 patent/US7890081B2/en not_active Expired - Fee Related
- 2005-10-07 WO PCT/FR2005/002476 patent/WO2006040453A2/fr active Application Filing
- 2005-10-07 EP EP05809116A patent/EP1844544A2/fr not_active Withdrawn
Non-Patent Citations (1)
Title |
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See references of WO2006040453A2 * |
Also Published As
Publication number | Publication date |
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FR2876517A1 (fr) | 2006-04-14 |
WO2006040453A3 (fr) | 2007-04-05 |
FR2876517B1 (fr) | 2009-04-10 |
US7890081B2 (en) | 2011-02-15 |
WO2006040453A2 (fr) | 2006-04-20 |
US20080064433A1 (en) | 2008-03-13 |
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