WO2005018118A1 - 歪み発生回路およびプリディストーション回路、並びにこれを用いた光信号送信機および光信号伝送システム - Google Patents
歪み発生回路およびプリディストーション回路、並びにこれを用いた光信号送信機および光信号伝送システム Download PDFInfo
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- WO2005018118A1 WO2005018118A1 PCT/JP2004/011553 JP2004011553W WO2005018118A1 WO 2005018118 A1 WO2005018118 A1 WO 2005018118A1 JP 2004011553 W JP2004011553 W JP 2004011553W WO 2005018118 A1 WO2005018118 A1 WO 2005018118A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/50—Transmitters
- H04B10/58—Compensation for non-linear transmitter output
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/50—Transmitters
- H04B10/516—Details of coding or modulation
- H04B10/548—Phase or frequency modulation
Definitions
- the present invention relates to a distortion generating circuit and a predistortion circuit used for optical signal transmission of a wideband signal, an optical signal transmitter using the predistortion circuit, and an optical signal transmission using the optical signal transmitter.
- a distortion generation circuit used for optical signal transmission of a multi-channel video signal that has been frequency-division multiplexed and that has been subjected to amplitude modulation (AM) or quadrature amplitude modulation (QAM).
- AM amplitude modulation
- QAM quadrature amplitude modulation
- the present invention relates to a predistortion circuit, an optical signal transmitter using the predistortion circuit, and an optical signal transmission system using the optical signal transmitter.
- an optical signal transmitter and an optical signal transmission system for optically transmitting a multi-channel video signal subjected to frequency division multiplexed amplitude modulation or quadrature amplitude modulation a video signal multiplexed by frequency division multiplexing is used.
- optical signal transmitters and optical signal transmission systems that use the FM-block conversion method to perform frequency modulation.
- FIG. 1 shows a configuration of a conventional optical signal transmitter and an optical signal transmission system using the FM-to-Batch conversion method.
- Figures 2A, 2B, and 2C show the signal formats at locations A, B, and C in Figure 1.
- the optical signal transmission system shown in FIG. 1 includes an optical signal transmitter 80 including an FM—conversion circuit 81, a light source 82, and an optical amplification circuit 83, an optical transmission line 85, a photoelectric conversion circuit 91, and an FM demodulation circuit.
- An optical signal receiver 90 provided with a 92, a set-top box 93, and a television receiver 94 are provided.
- 2A, 2B, and 2C show the signals A, B, and C in FIG. 1, respectively. Represents a spectrum. The same applies to A, B, and C in the following figures.
- a frequency-multiplexed video signal as shown in FIG. 2A is converted into one broadband frequency as shown in FIG. Converted to a modulated signal.
- the frequency modulation signal is intensity-modulated by a light source 82, further optically amplified by an optical amplifier circuit 83, and transmitted to an optical transmission line 85.
- the frequency-modulated signal that has been intensity-modulated is photoelectrically converted by the photoelectric conversion circuit 91 and returned to an electric signal.
- This electric signal is a wideband frequency-modulated signal, and is frequency-demodulated by the FM demodulation circuit 92 to demodulate a frequency-multiplexed video signal as shown in FIG. 2C.
- An appropriate video channel is selected from the demodulated video signal by a receiver 94 via a set-top box 93.
- FIG. 3 shows a configuration of an FM demodulation circuit applicable to the optical signal receiver 90.
- the FM demodulation circuit 92 shown in FIG. 3 is an FM demodulation circuit based on delay line detection, and includes a limiter amplifier 76, a delay f spring 77, an AND gate 78, and a rho-finolators 79.
- the input frequency modulated optical signal is shaped into a square wave by the limiter amplifier 76.
- the output of the limiter amplifier 76 is branched into two, one is input to the input terminal of the AND gate 78, and the other is inverted in polarity and then delayed by the time ⁇ by the delay line 77 to the input terminal of the power AND gate 78. Is entered.
- the output power of the AND gate 78 becomes a frequency demodulated output when smoothed by the one-pass filter 79 (for example, see Non-Patent Document 2).
- the FM demodulation circuit may be a two-tuned type frequency discriminator using a resonance circuit, a Foster Seely type frequency discriminator, There is a detection type FM demodulator.
- Low distortion is required for an optical signal transmitter and an optical signal transmission system using the FM-conversion conversion method.
- the CNR Carrier-to-Noise Ratio
- the CSO Composite Second-Order Distortion
- CTB Compositete Triple Beat
- Patent Document 2 describes a configuration in which a pre-distortion circuit is applied to distortion compensation of an FM batch conversion circuit.
- a pre-distortion circuit is configured using a distortion generating circuit composed of a non-linear element such as a diode, a FET, or a transistor to compensate for the distortion of the FM-combination circuit.
- the frequency-multiplexed AM that is input may be used. Since the signal frequencies of video and QAM video signals are wide, for example, from 93 MHz to 747 MHz, it has been difficult to compensate for all distortions of the FM-to-band conversion circuit over this wide band.
- Patent Document 1 Japanese Patent No. 2700622
- Patent Document 2 Japanese Patent No. 3371355
- Non-Special Noon Document 1 ITU-Tte quasi J. 185 ⁇ Transmission Equipment for transferring multi-channel televison signals over optical access networks by FM conversionj, ITU-T
- Non-Patent Document 2 Nobuteru Shibata et al., "FM—Optical Video Distribution System Using the Convergence Conversion Method," IEICE Transactions B, Vol. J83-B, No. 7, pp. 948-959, 2000 July, 2005
- Non-Patent Document 3 Suzuki et al., “Pulsed FM—Conversion-Modulated Analog Optical CATV Distribution System” IEICE Autumn Meeting, B-603, 1991
- the present invention even when an input electric signal over a wide frequency range is frequency-modulated by an FM-to-conversion circuit, distortion substantially equal to that of the FM-to-conversion circuit is generated. It is an object of the present invention to provide a distortion generating circuit that performs the following. It is another object of the present invention to provide a pre-distortion circuit that compensates for the distortion of the FM-to-BGA conversion circuit using the distortion generation circuit. It is another object of the present invention to provide an optical signal transmitter with less distortion using the pre-distortion circuit. Further, it is another object of the present invention to provide an optical signal transmission system that realizes transmission of a wideband signal such as a video signal with little distortion using the optical signal transmitter.
- a distortion generating circuit is a distortion generating circuit that generates a distortion substantially equal to the distortion of the FM-to-conversion circuit, and converts an input electric signal into an electric signal.
- a distribution circuit for distributing the signals into two electric signals, an FM-band conversion circuit for frequency-modulating and outputting one output from the distribution circuit, and an FM for demodulating and outputting the output of the FM-band conversion circuit A demodulation circuit, an amplitude delay adjustment circuit that performs amplitude adjustment and delay adjustment on the other output from the distribution circuit and outputs the result, and combines an output from the FM demodulation circuit and an output from the amplitude delay adjustment circuit. And a synthesizing circuit for outputting the result.
- the distribution circuit is a differential distribution circuit that distributes an input electric signal to two electric signals having phases inverted to each other, and the combining circuit includes the FM circuit.
- An in-phase synthesizing circuit that in-phase synthesizes an output from the demodulation circuit and an output from the amplitude delay adjustment circuit and outputs the same, or the distribution circuit is an in-phase distribution circuit that distributes an input electric signal to two electric signals.
- the synthesizing circuit may be a differential synthesizing circuit for differentially synthesizing an output from the FM demodulation circuit and an output from the amplitude delay adjusting circuit and outputting the result.
- the distortion generating circuit of the present invention includes a light source that outputs an optical signal obtained by intensity-modulating the output of the FM-converting circuit, and an optical signal that converts an optical signal output from the light source into an electric signal and outputs the electric signal. And a conversion circuit.
- the distortion generating circuit of the present invention can include an amplitude control terminal for adjusting the amplitude by external control and a delay control terminal for adjusting the delay by external control.
- the predistortion circuit includes a distributor that distributes an input electric signal into two electric signals, a delay line that delays one output from the distributor and outputs the delayed signal, A second amplitude delay adjusting circuit that performs amplitude adjustment and delay adjustment on the output from the distortion generating circuit and outputs the result, and an output from the delay line and the second amplitude delay adjusting circuit.
- the predistortion circuit of the present invention can include a differential distributor or an in-phase distributor as the distributor, and a differential combiner or an in-phase combiner as the combiner.
- an optical signal transmitter includes the distortion generating circuit according to the present invention or the predistortion circuit according to the present invention.
- an optical signal transmission system of the present invention includes the distortion generating circuit of the present invention.
- the distortion generating circuit of the present invention even when an input electric signal over a wide frequency range is frequency-modulated by the FM-bridge conversion circuit, generates distortion substantially equal to that of the FM-bridge conversion circuit. be able to.
- the predistortion circuit of the present invention can output the inverse distortion for compensating for the distortion of the FM-block conversion circuit by using this distortion generation circuit.
- the optical signal transmitter of the present invention can transmit an optical signal with less distortion by using the pre-distortion circuit.
- the optical signal transmission system of the present invention can realize transmission of a wideband signal such as a video signal with little distortion using the optical signal transmitter.
- FIG. 1 is a diagram illustrating a configuration of a conventional optical signal transmitter and an optical signal transmission system using an FM-to-band conversion method.
- FIG. 2A is a diagram illustrating a signal spectrum in an optical signal transmitter and an optical signal transmission system.
- FIG. 2B is a diagram illustrating a signal spectrum in the optical signal transmitter and the optical signal transmission system.
- FIG. 2C is a diagram illustrating a signal spectrum in the optical signal transmitter and the optical signal transmission system.
- FIG. 3 is a diagram illustrating a configuration of an FM demodulation circuit applicable to an optical signal receiver.
- FIG. 4 is a diagram illustrating a configuration of a distortion generating circuit applicable to a predistortion circuit and an optical signal transmitter.
- FIG. 5 is a diagram illustrating a configuration of a distortion generating circuit applicable to a predistortion circuit and an optical signal transmitter.
- FIG. 6 is a diagram illustrating a configuration of a distortion generating circuit applicable to a predistortion circuit and an optical signal transmitter.
- FIG. 7 is a diagram illustrating a configuration of a distortion generating circuit applicable to a predistortion circuit and an optical signal transmitter.
- FIG. 8 is a diagram illustrating a configuration of an FM-bundling conversion circuit applied to a distortion generating circuit, which uses an optical frequency modulation unit.
- FIG. 9 is a diagram illustrating an FM-bundling conversion circuit applied to a distortion generating circuit, in which two optical frequency modulation sections are used in a push-pull configuration.
- FIG. 10 is a diagram for explaining a configuration of an FM-bundling conversion circuit applied to a distortion generating circuit, which uses a voltage-controlled oscillator.
- FIG. 11 is a diagram illustrating an FM-bridge conversion circuit applied to a distortion generation circuit, which uses two voltage-controlled oscillators in a push-pull configuration.
- FIG. 12 is a diagram illustrating a configuration of a pre-distortion circuit using a distortion generation circuit.
- FIG. 13 is a diagram illustrating a configuration of a pre-distortion circuit using a distortion generation circuit.
- FIG. 14 is a diagram illustrating a configuration of a pre-distortion circuit using a distortion generation circuit.
- FIG. 15 is a diagram illustrating a configuration of a pre-distortion circuit using a distortion generation circuit.
- FIG. 16 is a diagram illustrating a configuration of an optical signal transmitter using a predistortion circuit.
- FIG. 17 is a diagram illustrating a configuration of an optical signal transmitter using a distortion generation circuit.
- FIG. 18 is a diagram illustrating a configuration of an optical signal transmitter using a distortion generation circuit.
- FIG. 19 is a diagram illustrating a configuration of an optical signal transmission system including an optical signal transmitter having a distortion generating circuit and a predistortion circuit and an optical signal receiver.
- FIG. 20 is a diagram illustrating a configuration of a distortion generating circuit applicable to a predistortion circuit and an optical signal transmitter.
- FIG. 21 is a diagram illustrating a configuration of a distortion generating circuit applicable to a predistortion circuit and an optical signal transmitter.
- FIG. 22 is a diagram illustrating a configuration of a distortion generating circuit applicable to a predistortion circuit and an optical signal transmitter.
- FIG. 23 is a diagram illustrating a configuration of a distortion generating circuit applicable to a predistortion circuit and an optical signal transmitter.
- the present embodiment is an embodiment of a distortion generating circuit. 4 and 20 show the configuration of the distortion generating circuit according to the present embodiment.
- the distortion generation circuit 16 shown in FIG. 4 includes an FM—conversion circuit 12, a differential distribution circuit 21, an in-phase synthesis circuit 37, an amplitude adjustment circuit 38, a delay adjustment circuit 39, and an FM demodulation circuit 92. .
- the distortion generation circuit 16 shown in FIG. 20 further includes an amplitude control terminal 101 for adjusting the amplitude of the output of the amplitude adjustment circuit 38, and a delay control terminal 102 for adjusting the delay of the output of the delay adjustment circuit 39.
- the electric signal input to the differential distribution circuit 21 is distributed to two electric signals of 0 phase and ⁇ phase whose phases are inverted from each other.
- One of the divided electric signals is input to the F / C conversion circuit 12, and the other is input to the amplitude adjustment circuit 38.
- the FM—conversion converter circuit 12 frequency-modulates one output from the differential distribution circuit 21 and outputs the result to the FM demodulation circuit 92.
- the FM demodulation circuit 92 demodulates the frequency of the frequency-modulated electric signal and outputs it to the in-phase synthesis circuit 37.
- the in-phase synthesizing circuit 37 in-phase synthesizes the output from the FM demodulation circuit 92 and the output from the delay adjustment circuit 39 and outputs the result.
- the in-phase synthesizing circuit 37 After the phase is reversed in the differential distribution circuit 21, the signals are synthesized with the same amplitude and the same delay amount, so that the two input electric signals are canceled each other. However, if there is distortion in both or any one of the FM-block conversion circuit 12 and the FM demodulation circuit 92, the in-phase synthesis circuit 37 outputs the distortion.
- the output to the FM-combination conversion circuit 12 is set to 0 phase, and the amplitude is adjusted.
- the output to the circuit 38 is ⁇ -phase
- the output of the distortion generation circuit 16 outputs the same phase distortion as the distortion generated by the FM-block conversion circuit 12 and the FM demodulation circuit 92.
- the output of the distortion generation circuit 16 is the distortion generated by the FM—band conversion circuit 12 and the FM demodulation circuit 92. Outputs anti-phase distortion.
- the amplitude adjustment circuit 38 has an amplitude control terminal 101 for adjusting the output amplitude
- the delay adjustment circuit 39 has a delay control terminal 102 for adjusting the output delay.
- the amplitude and delay can be adjusted by an external input.
- the FM-band conversion circuit 12 and the FM demodulation circuit 92 used are the FM-band conversion circuit of the optical signal transmitter and the optical signal receiver to which the distortion generation circuit 16 is applied.
- both the amplitude adjustment circuit 38 and the delay adjustment circuit 39 are linear circuits, the order may be reversed. Further, the amplitude adjustment circuit 38 and the delay adjustment circuit 39 may be arranged on the side of the FM-combination circuit 12 in order to adjust the amplitude and delay of the input to the in-phase synthesis circuit 37.
- the distortion generation circuit 16 of the present embodiment is equivalent to the distortion generated by the FM-to-FM conversion circuit and the FM demodulation circuit of the optical signal transmitter and optical signal receiver to which the distortion generation circuit 16 is applied. Can be output.
- the present embodiment is another embodiment of the distortion generating circuit.
- 5 and 21 show the configuration of the distortion generation circuit according to the present embodiment.
- the distortion generating circuit 16 shown in FIG. 5 includes an FM-blocking conversion circuit 12, an amplitude adjustment circuit 38, a delay adjustment circuit 39, an in-phase distribution circuit 48, a differential synthesis circuit 49, and an FM demodulation circuit 92.
- the distortion generating circuit 16 shown in FIG. 21 further includes an amplitude control terminal 101 for adjusting the output amplitude of the amplitude adjustment circuit 38, and a delay control terminal 102 for adjusting the output delay of the delay adjustment circuit 39.
- the electric signal input to the in-phase distribution circuit 48 is distributed to two electric signals having the same phase.
- One of the divided electric signals is input to the FM-block conversion circuit 12, and the other is input to the amplitude adjustment circuit 38.
- the FM-bundling conversion circuit 12 frequency-modulates one output from the in-phase distribution circuit 48 and outputs it to the FM demodulation circuit 92.
- the FM demodulation circuit 92 demodulates the frequency of the frequency-modulated electric signal and outputs it to the differential synthesis circuit 49.
- the amplitude adjustment circuit 38 and the delay adjustment circuit 39 are connected to each other from the common-mode distribution circuit 48 so that the amplitude and the delay of the electric signal from the FM demodulation circuit 92 and the delay adjustment circuit 39 are matched by the differential synthesis circuit 49. The output of this is adjusted in amplitude and delay and output to the differential combining circuit 49.
- the differential synthesis circuit 49 performs differential synthesis on the output from the FM demodulation circuit 92 and the output from the delay adjustment circuit 39 and outputs the result.
- the differential combining circuit 49 After being distributed by the in-phase distribution circuit 48, the signals are combined with the same amplitude and the same delay amount and in opposite phases, so that the two input electric signals are canceled each other. However, if there is a distortion in either or both of the FM batch conversion circuit 12 and the FM demodulation circuit 92, the differential synthesis circuit 49 outputs the distortion.
- the FM demodulation circuit When the input phase of the differential combining circuit 49 for differentially combining the output from the FM demodulation circuit 92 and the output from the delay adjustment circuit 39 is set to 0 phase and ⁇ phase, the FM demodulation circuit When the output from the output 92 is 0-phase and the output from the delay adjustment circuit 39 is differentially combined as the ⁇ -phase, the output of the distortion generation circuit 16 is in the same phase as the distortion generated by the FM-combination conversion circuit 12 and the FM demodulation circuit 92. Outputs distortion.
- the output of the distortion generation circuit 16 is the distortion generated by the FM-combination conversion circuit 12 and the FM demodulation circuit 92. And output the opposite phase distortion.
- the amplitude adjustment circuit 38 adjusts the output amplitude.
- An amplitude control terminal 101 is provided, and the delay adjustment circuit 39 is provided with a delay control terminal 102 for adjusting an output delay amount, and the amplitude amount and the delay amount can be adjusted by an external input.
- the FM-band conversion circuit 12 and the FM demodulation circuit 92 used are the FM-band conversion circuit of the optical signal transmitter and the optical signal receiver to which the distortion generation circuit 16 is applied.
- both the amplitude adjustment circuit 38 and the delay adjustment circuit 39 are linear circuits, the order may be reversed. Further, the amplitude adjustment circuit 38 and the delay adjustment circuit 39 may be arranged on the side of the FM-total conversion circuit 12 in order to adjust the amplitude and delay of the input to the differential synthesis circuit 49.
- the distortion generation circuit 16 of the present embodiment is equivalent to the distortion generated by the FM-to-FM conversion circuit and the FM demodulation circuit of the optical signal transmitter and the optical signal receiver to which the distortion generation circuit 16 is applied. Can be output.
- This embodiment is another embodiment of the distortion generating circuit. 6 and 22 show the configuration of the distortion generation circuit according to the present embodiment.
- the distortion generating circuit 16 shown in FIG. 6 includes an FM-to-conversion circuit 12, a differential distribution circuit 21, an in-phase synthesis circuit 37, an amplitude adjustment circuit 38, a delay adjustment circuit 39, a light source 82, and a photoelectric conversion circuit. 91 and an FM demodulation circuit 92.
- the distortion generating circuit 16 shown in FIG. 22 further includes an amplitude control terminal 101 for adjusting the output amplitude of the amplitude adjustment circuit 38 and a delay control terminal 102 for adjusting the output delay of the delay adjustment circuit 39.
- the difference from the first embodiment is that a light source 82 and a photoelectric conversion circuit 91 are added, and conversion into an optical signal and inverse conversion are performed between frequency modulation and frequency demodulation. That is, in FIGS. 6 and 22, the electric signal input to the differential distribution circuit 21 is distributed to two electric signals of 0 phase and ⁇ phase whose phases are inverted from each other. One of the divided electric signals is input to the FM-block conversion circuit 12, and the other is input to the amplitude adjustment circuit 38.
- the FM-bundling conversion circuit 12 frequency-modulates one output from the differential distribution circuit 21 and outputs it to the light source 82.
- the light source 82 converts the frequency-modulated electric signal into an optical signal and outputs the optical signal to the photoelectric conversion circuit 91.
- the photoelectric conversion circuit 91 converts the optical signal into an electric signal and outputs the electric signal to the FM demodulation circuit 92.
- the FM demodulation circuit 92 frequency-demodulates the frequency-modulated electric signal and outputs it to the in-phase synthesis circuit 37.
- the amplitude adjusting circuit 38 and the delay adjusting circuit 39 are connected to each other by the in-phase synthesizing circuit 37 so that the amplitude and the delay of the electric signal from the FM demodulating circuit 92 and the delay adjusting circuit 39 coincide with each other.
- the output is adjusted to the amplitude and delay, and output to the in-phase synthesis circuit 37.
- the in-phase synthesizing circuit 37 in-phase synthesizes the output from the FM demodulation circuit 92 and the output from the delay adjustment circuit 39 and outputs the result.
- the in-phase synthesizing circuit 37 After the phase is reversed by the differential distribution circuit 21, the signals are synthesized with the same amplitude and the same delay amount, so that the two input electric signals are canceled each other. However, if all or any one of the FM-blocking conversion circuit 12, the light source 82, the photoelectric conversion circuit 91, and the FM demodulation circuit 92 has a distortion, the in-phase synthesis circuit 37 outputs the distortion.
- the output phase of the differential distribution circuit 21 for distributing two electric signals whose phases are inverted to each other is set to 0 phase and ⁇ phase
- the output to the FM-combination conversion circuit 12 is set to 0 phase, and the amplitude is adjusted.
- the output to the circuit 38 is ⁇ -phase
- the output of the distortion generation circuit 16 outputs the same phase distortion as the distortion generated by the FM-block conversion circuit 12, the light source 82, the photoelectric conversion circuit 91, and the FM demodulation circuit 92.
- the output of the distortion generation circuit 16 is the output of the FM conversion circuit 12, the light source 82, the photoelectric conversion circuit 91, Outputs a distortion having a phase opposite to the distortion generated by the FM demodulation circuit 92.
- the amplitude adjustment circuit 38 has an amplitude control terminal 101 for adjusting the output amplitude
- the delay adjustment circuit 39 has a delay control terminal 102 for adjusting the output delay.
- the amplitude and delay can be adjusted by an external input.
- the FM-block conversion circuit 12, the light source 82, the photoelectric conversion circuit 91, and the FM demodulation circuit 92 used are an optical signal transmitter to which the distortion generation circuit 16 is applied, and an optical signal transmitter.
- the signal receiver preferably has the same or close distortion characteristics as the FM converter, the light source as the transmission circuit, the photoelectric conversion circuit, and the FM demodulation circuit.
- both the amplitude adjustment circuit 38 and the delay adjustment circuit 39 are linear circuits, the order may be reversed. Further, the amplitude adjustment circuit 38 and the delay adjustment circuit 39 may be arranged on the side of the FM-combination circuit 12 in order to adjust the amplitude and delay of the input to the in-phase synthesis circuit 37. Therefore, in the distortion generating circuit 16 of the present embodiment, the optical signal transmitter to which the distortion generating circuit 16 is applied, the FM-to-optical conversion circuit of the optical signal receiver, the light source, the photoelectric conversion circuit, and the FM demodulation circuit Can be output as a distortion equivalent to the distortion that occurs.
- This embodiment is another embodiment of the distortion generating circuit. 7 and 23 show the configuration of the distortion generation circuit according to the present embodiment.
- the distortion generating circuit 16 shown in FIG. 7 includes an FM-blocking conversion circuit 12, an amplitude adjustment circuit 38, a delay adjustment circuit 39, an in-phase distribution circuit 48, a differential combining circuit 49, a light source 82, and a photoelectric conversion circuit. 91 and an FM demodulation circuit 92.
- the distortion generating circuit 16 shown in FIG. 23 further includes an amplitude control terminal 101 for adjusting the output amplitude of the amplitude adjustment circuit 38, and a delay control terminal 102 for adjusting the output delay of the delay adjustment circuit 39.
- the difference from the second embodiment is that a light source 82 and a photoelectric conversion circuit 91 are added, and conversion into an optical signal and inverse conversion are performed between frequency modulation and frequency demodulation. That is, in FIGS. 7 and 23, the electric signal input to the in-phase distribution circuit 48 is distributed to two electric signals having the same phase.
- the FM-bundling conversion circuit 12 frequency-modulates one output from the in-phase distribution circuit 48 and outputs it to the light source 82.
- the light source 82 converts the frequency-modulated electric signal into an optical signal and outputs it to the photoelectric conversion circuit 91.
- the photoelectric conversion circuit 91 converts the optical signal into an electric signal and outputs the electric signal to the FM demodulation circuit 92.
- the FM demodulation circuit 92 demodulates the frequency of the frequency-modulated electric signal and outputs it to the differential synthesis circuit 49.
- the amplitude adjusting circuit 38 and the delay adjusting circuit 39 are connected to each other by the differential synthesizing circuit 49 so that the amplitude and the delay of the electric signal from the FM demodulating circuit 92 and the delay adjusting circuit 39 coincide with each other.
- the output is amplitude-adjusted and delay-adjusted and output to the differential synthesis circuit 49.
- the differential combining circuit 49 performs differential combining of the output from the FM demodulation circuit 92 and the output from the delay adjustment circuit 39 and outputs the result.
- the differential combining circuit 49 After being distributed by the in-phase distribution circuit 48, the signals are combined with the same amplitude and the same delay amount and in opposite phases, so that the two input electric signals are canceled each other. However, all of the FM batch conversion circuit 12, light source 82, photoelectric conversion circuit 91, and FM demodulation circuit 92 If any of them has a distortion, the differential combining circuit 49 outputs the distortion.
- the FM demodulation circuit When the input phase of the differential combining circuit 49 for differentially combining and outputting the output from the FM demodulation circuit 92 and the output from the delay adjustment circuit 39 is 0 phase and ⁇ phase, the FM demodulation circuit When the output from the 92 is differentially combined with the output from the 0 phase and the output from the delay adjustment circuit 39 as the ⁇ phase, the output from the distortion generation circuit 16 is the FM—bundling conversion circuit 12, light source 82, photoelectric conversion circuit 91, and FM demodulation circuit 92 And outputs a distortion having the same phase as the distortion generated.
- the output from the FM demodulation circuit 92 When the output from the FM demodulation circuit 92 is differentially combined with the ⁇ -phase output from the delay adjustment circuit 39 and the output from the delay adjustment circuit 39 as the 0-phase, the output from the distortion generation circuit 16 becomes the FM-bundling conversion circuit 12, light source 82, photoelectric conversion circuit 91, Outputs a distortion having a phase opposite to the distortion generated by the demodulation circuit 92.
- the amplitude adjustment circuit 38 has an amplitude control terminal 101 for adjusting the output amplitude
- the delay adjustment circuit 39 has a delay control terminal 102 for adjusting the output delay.
- the amplitude and delay can be adjusted by an external input.
- the FM-to-conversion circuit 12, the light source 82, the photoelectric conversion circuit 91, and the FM demodulation circuit 92 used are an optical signal transmitter to which the distortion generation circuit 16 is applied, an optical signal It is preferable that the distortion characteristics be the same as or close to those of the FM-to-converter circuit of the receiver, the light source as the transmitting circuit, the photoelectric conversion circuit and the FM demodulation circuit.
- both the amplitude adjustment circuit 38 and the delay adjustment circuit 39 are linear circuits, the order may be reversed. Further, the amplitude adjustment circuit 38 and the delay adjustment circuit 39 may be arranged on the side of the FM-total conversion circuit 12 in order to adjust the amplitude and delay of the input to the differential synthesis circuit 49.
- the optical signal transmitter to which the distortion generation circuit 16 is applied the FM-to-optical conversion circuit of the optical signal receiver, the light source as the transmission circuit, the photoelectric conversion circuit, and the FM A distortion equivalent to the distortion generated by the demodulation circuit can be output.
- the present embodiment is applied to an FM global conversion circuit that can be used for the distortion generation circuits of the first to fourth embodiments, that is, the distortion generation circuit 16 in FIGS. 4 to 7 or FIGS. 20 to 23.
- This is an embodiment of the FM-bundling conversion circuit 12 that can be used.
- FIG. 8 shows an FM-to-FM converter using an optical frequency modulator and an optical frequency local oscillator.
- . 8 includes an optical frequency modulation unit 22, an optical multiplexer 23, an optical detector 24, and an optical frequency local oscillation unit 32.
- the optical frequency Ffmld of the optical signal at the output of the optical frequency modulation section 22 becomes If the deviation is S f,
- a DFB-LD distributed Feed-Back Laser Diode, distributed feedback semiconductor laser
- the optical frequency local oscillator 32 oscillates using an oscillating light source having an optical frequency fl, and multiplexes the optical signal from the optical frequency modulator 22 with the optical multiplexer 23.
- DFB-LD can be used as the oscillation light source of the optical frequency local oscillator 32.
- the two optical signals multiplexed by the optical multiplexer 23 are detected by a photodiode which is an optical heterodyne detector 24.
- the frequency f of the detected electrical signal is
- the intermediate frequency fi fo ⁇ fl as shown in FIG. It is possible to obtain a frequency-modulated electric signal having a frequency shift ⁇ f.
- the optical frequency of a DFB-LD is modulated by an injection current, and its optical frequency fluctuates in a width of several GHz with the injection current. Therefore, a value of several GHz can be obtained as the frequency shift ⁇ f. it can.
- a distortion generating circuit that can generate distortion equivalent to the distortion generated in the FM-band conversion circuit and the like by the FM-band conversion circuit using the optical frequency modulation unit and the optical frequency local oscillation unit is provided. Can be configured.
- the present embodiment can be used for the distortion generating circuits of the first to fourth embodiments.
- Fig. 9 shows an FM-bundling conversion circuit using two optical frequency modulation sections in a push-pull configuration.
- 9 includes a differential distributor 25, an optical frequency modulator 22-1, an optical frequency modulator 22-2, an optical multiplexer 23, and an optical detector 24. .
- the frequency-multiplexed video signal as shown in FIG. 2A is distributed by the differential distribution unit 25 as two electric signals of 0 phase and ⁇ phase whose phases are inverted with respect to each other. .
- the optical frequency modulation unit 22_1 performs frequency modulation using a carrier light source of the optical frequency fol, the frequency shift becomes ⁇ f / 2, the optical frequency Ffmldl of the optical signal at the output of the optical frequency modulator 22-1 is
- Ffmldl fol + ( ⁇ f / 2)-sin (2 ⁇ -fs -t) (3)
- the modulation signal is a signal of frequency fs.
- the ⁇ -phase electric signal of the two electric signals from the differential distributor is used as the modulation input and the optical frequency modulation unit 22-2 performs frequency modulation using the carrier light source of the frequency fo2, the frequency shift becomes ⁇ f / When 2, the optical frequency of the optical signal at the output of the optical frequency modulator 22-2 is Ffmld2,
- Ffmld2 fo2- (5 f / 2)-sin (2 ⁇ -fs -t) (4)
- DFB-LD distributed Feed-Back Laser Diode, distributed feedback semiconductor laser
- DFB-LD distributed Feed-Back Laser Diode, distributed feedback semiconductor laser
- the outputs from the optical frequency modulators 22-1 and 22-2 are multiplexed by the optical multiplexer 23, and the two optical signals multiplexed by the optical multiplexer 23 are heterodyne-detected by the optical detector 23.
- the optical detector a photodiode functioning as a heterodyne detector can be used.
- the frequency f of the electric signal subjected to heterodyne detection by the optical detector 24 an electric signal having a frequency having a difference between the values represented by the above-described equations (3) and (4) is obtained. That is,
- the intermediate frequency as shown in FIG. fi fo—Fl is several GHz and frequency-modulated electric signal with frequency shift ⁇ f can be obtained.
- the DFB-LD is modulated by the injection current, and the optical frequency fluctuates in a width of several GHz with the injection current. Therefore, a value of several GHz can be obtained as the frequency deviation ⁇ f. it can.
- a distortion generating circuit capable of generating the same distortion as the distortion generated in the FM-band conversion circuit or the like is configured by the FM-band conversion circuit using the two optical frequency modulation sections in a push-pull configuration. can do.
- the present embodiment is applied to an FM global conversion circuit that can be used in the distortion generating circuits of the first to fourth embodiments, that is, the distortion generating circuit 16 in FIGS. 4 to 7 or FIGS. 20 to 23.
- This is an embodiment of the FM-bundling conversion circuit 12 that can be used.
- FIG. 10 shows an FM-block converter using a voltage-controlled oscillator.
- the FM-to-Batch conversion circuit 12 shown in FIG. 10 shows an FM-block converter using a voltage-controlled oscillator.
- the modulation signal is a signal of frequency fs.
- the FM-bundling conversion circuit using the voltage-controlled oscillator makes it possible to use the FM-bundling conversion circuit and the like.
- a distortion generating circuit capable of generating a distortion equivalent to the distortion generated in the above.
- the present embodiment is applied to an FM global conversion circuit that can be used in the distortion generating circuits of the first to fourth embodiments, that is, the distortion generating circuit 16 in FIGS. 4 to 7 or FIGS. 20 to 23.
- This is an embodiment of the FM-bundling conversion circuit 12 that can be used.
- FIG. 11 shows a configuration of an FM-block converter using two voltage-controlled oscillators in a push-pull configuration.
- 11 includes a differential distribution section 25, a voltage controlled oscillator 28-1, a voltage controlled oscillator 28-2, a mixer 29, and a low-pass filter 30.
- the frequency-multiplexed video signal as shown in FIG. 2A is distributed to two electric signals whose phases are inverted by the differential distribution unit 25.
- Differential distribution unit 25 When the voltage-controlled oscillator 28-1 frequency-modulates the zero-phase electric signal of the two electric signals whose phases are inverted from each other with the center frequency of the frequency fo, the output electric signal is obtained.
- the frequency fvl of is, when the frequency shift is ⁇ f / 2,
- the modulation signal is a signal of the frequency fs.
- the ⁇ -phase electric signal of the two electric signals whose phases are inverted from each other from the differential distribution unit 25 is used as the modulation input, and the voltage is controlled by the voltage-controlled oscillator 28-2 so that the frequency f ol is the center frequency.
- the frequency fv2 of the output electric signal is, when the frequency shift is ⁇ f / 2,
- the outputs from the voltage controlled oscillators 28_1 and 28-2 are mixed by the mixer 29, and the two electric signals mixed by the mixer 29 are smoothed by the low-pass filter 30.
- the frequency f of the electric signal smoothed by the low-pass filter 30, which passes the electric signal of the frequency, is equal to the difference between the intermediate frequency f ol and the intermediate frequency fo2.
- An electric signal having a frequency equal to the difference represented by is obtained. That is,
- a distortion generating circuit capable of generating the same distortion as the distortion generated in the FM-bridge conversion circuit or the like is configured by the FM-bridge conversion circuit using two voltage-controlled oscillators in a push-pull configuration. be able to.
- the present embodiment is a pre-distortion circuit using any of the distortion generating circuits described in the first to eighth embodiments.
- FIG. 12 shows the configuration of the predistortion circuit of the present embodiment.
- the pre-distortion circuit 41 shown in FIG. 12 includes a distortion generation circuit 16, a differential distributor 18, a differential synthesizer 40, a delay line 43, an amplitude adjustment circuit 45, and a delay adjustment circuit 46. .
- differential distributor 18 divides an input electric signal into two electric signals having phases inverted from each other, and outputs the electric signal to delay line 43 and distortion generating circuit 16.
- the distortion generating circuit 16 of the present embodiment is a distortion generating circuit which is one of the distortion generating circuits described in the first to eighth embodiments. This is a distortion generation circuit that outputs distortion that is out of phase with the distortion generated by the conversion circuit, light source, photoelectric conversion circuit, and FM demodulation circuit.
- the delay line 43 delays one output from the differential distributor 18 and outputs it to the differential synthesizer 40.
- the distortion generation circuit 16 outputs the distortion from the other output from the differential distributor 18 to the amplitude adjustment circuit 45.
- the amplitude adjustment circuit 45 and the delay adjustment circuit 46 adjust the amplitude and delay of the output from the distortion generation circuit 16 so as to minimize the distortion generated by the FM-combination conversion circuit that connects the pre-distortion circuit.
- the differential combiner 40 differentially combines the output from the delay line 43 and the output from the delay adjustment circuit 46 with a phase that cancels the distortion of the circuit connecting the predistortion circuit 41, and outputs the combined result.
- the phase of the output of the differential distributor 18 that distributes the two electric signals whose phases are inverted to each other is 0 phase and ⁇ phase
- the output to the delay line 43 is 0 phase
- the output to the distortion generation circuit 16 is Is the ⁇ -phase
- the output of the delay line 43 and the output of the delay adjustment circuit 46 are differentially combined and output.
- the phase of the electric signal at the output of the predistortion circuit 41 is the same as the phase of the electric signal at the input of the predistortion circuit 41.
- the distortion at the output of the pre-distortion circuit 41 is caused by the FM batch conversion circuit and the FM demodulation circuit of the distortion generation circuit 16 or the FM-band conversion circuit, the light source, the photoelectric conversion circuit, and the FM demodulation circuit. And reverse-phase distortion.
- the output phase of the differential distributor 18 for distributing the two electric signals whose phases are inverted to each other is 0 phase and ⁇ phase
- the output to the delay line 43 is ⁇ phase
- the distortion generation circuit The output to 16 is set to 0 phase
- the phase of the input of the differential combiner 40 that differentially synthesizes the output from the delay line 43 and the output from the delay adjustment circuit 46 is set to 0 phase and ⁇ phase.
- the phase of the electric signal at the output of the pre-distortion circuit 41 becomes The distortion at the output of the pre-distortion circuit 41 is the same as the phase, and the distortion generated by the FM—bundling conversion circuit and FM demodulation circuit of the distortion generation circuit 16 or the FM—bundling conversion circuit, light source, photoelectric conversion circuit, and FM This is a distortion having the opposite phase to the distortion generated by the demodulation circuit.
- the pre-distortion circuit 41 cancels the distortion of the wide-band signal such as the video signal to be input, which is generated by the FM-block conversion circuit or the like that connects the pre-distortion circuit 41. It is possible to add distortion of opposite phase in advance and output.
- both the amplitude adjustment circuit 45 and the delay adjustment circuit 46 are linear circuits, the order may be reversed.
- the amplitude adjustment circuit 45 and the delay adjustment circuit 46 are arranged on the side of the delay line 43 to adjust the amplitude and delay of the input to the differential combiner 40, and the functions of the delay line 43 and the function are degenerated. Is also good.
- a distortion having a phase opposite to that of the distortion generated in the FM-combination conversion circuit and the like connected downstream of the pre-distortion circuit 41 is added.
- a wideband signal can be output.
- the present embodiment is a pre-distortion circuit using any of the distortion generating circuits described in Embodiments 1 to 8.
- FIG. 13 shows the configuration of the predistortion circuit of the present embodiment.
- the predistortion circuit 41 shown in FIG. 13 includes the distortion generating circuit 16, the differential distributor 18, the delay line 43, the amplitude adjusting circuit 45, the delay adjusting circuit 46, and the in-phase synthesizer 50.
- differential distributor 18 divides an input electric signal into two electric signals having phases inverted to each other, and outputs the electric signal to delay line 43 and distortion generating circuit 16.
- the distortion generating circuit 16 of the present embodiment is a distortion generating circuit which is one of the distortion generating circuits described in the first to eighth embodiments. This is a distortion generation circuit that outputs the same phase distortion as the distortion generated by the conversion circuit, light source, photoelectric conversion circuit, and FM demodulation circuit.
- the delay line 43 delays one output from the differential distributor 18 and outputs it to the in-phase combiner 50.
- the distortion generation circuit 16 outputs the distortion from the other output from the differential distributor 18 to the amplitude adjustment circuit 45.
- the amplitude adjustment circuit 45 and the delay adjustment circuit 46 adjust the amplitude and delay of the output from the distortion generation circuit 16 so that the distortion generated by the FM-combined conversion circuit to which the pre-distortion circuit is connected is minimized.
- the in-phase combiner 50 is a phase for canceling the distortion of the circuit connected to the pre-distortion circuit 41, and in-phase combines the output from the delay line 43 and the output from the delay adjustment circuit 46 to output.
- the output phase of the differential distributor 18 for distributing two electric signals whose phases are inverted to each other is 0 phase and ⁇ phase
- the output to the delay line 43 is 0 phase
- the output to the distortion generation circuit 16 is Is the phase of the electric signal at the output of the predistortion circuit 41
- the phase of the electric signal at the input of the predistortion circuit 41 is in phase
- the distortion at the output of the predistortion circuit 41 is Distortion generated by the FM-bundling conversion circuit and the FM demodulation circuit, or distortion in the opposite phase to the distortion generated by the FM-bundling conversion circuit, the light source, the photoelectric conversion circuit, and the FM demodulation circuit.
- the output of the differential distributor 18 for distributing the two electric signals whose phases are inverted to each other is obtained.
- the phases are 0 and ⁇
- the output to the delay line 43 is ⁇
- the output to the distortion generator 16 is 0
- the output from the delay line 43 and the output from the delay adjustment circuit 46 are Assuming that both phases of the input of the in-phase synthesizer 50 that outputs the same in phase are the ⁇ -phase, that is, an inverting type in-phase synthesizer, the phase force of the electric signal output from the pre-distortion circuit 41 and the input of the input of the pre-distortion circuit 41
- the phase at the output of the pre-distortion circuit 41 becomes in-phase with the electric signal, and the distortion generated by the FM-bundling conversion circuit and the FM demodulation circuit of the distortion generating circuit 16 or the FM-bundling conversion circuit, the light source, and the photoelectric conversion This is the opposite phase of the distortion generated by the circuit and the FM demodulation circuit.
- the pre-distortion circuit 41 cancels the distortion of the wide band signal such as the video signal to be input, which is generated by the FM-combination conversion circuit or the like that connects the pre-distortion circuit 41 to the wide band signal. It is possible to add distortion of opposite phase in advance and output.
- both the amplitude adjustment circuit 45 and the delay adjustment circuit 46 are linear circuits, the order may be reversed.
- the amplitude adjustment circuit 45 and the delay adjustment circuit 46 are arranged on the side of the delay line 43 to adjust the amplitude and delay of the input to the differential combiner 40, and the functions of the delay line 43 and the function are degenerated. Is also good.
- the pre-distortion circuit 41 of the present embodiment outputs a wide-band signal to which distortion in the opposite phase to the distortion generated in the FM-combination circuit or the like connected at the subsequent stage of the pre-distortion circuit 41 is added. be able to.
- the present embodiment is a pre-distortion circuit using any of the distortion generating circuits described in Embodiments 1 to 8.
- FIG. 14 shows the configuration of the predistortion circuit of the present embodiment.
- the pre-distortion circuit 41 shown in FIG. 14 includes a distortion generation circuit 16, an in-phase distributor 19, a differential synthesizer 40, a delay line 43, an amplitude adjustment circuit 45, and a delay adjustment circuit 46.
- in-phase distributor 19 distributes an input electric signal into two electric signals and outputs the electric signal to delay line 43 and distortion generating circuit 16.
- the distortion generation circuit 16 of the present embodiment is the distortion generation circuit described in the first to eighth embodiments, and the FM—conversion conversion of the distortion generation circuit 16 is performed.
- This is a distortion generating circuit that outputs the same distortion as the distortion generated by the circuit and the FM demodulation circuit, or the distortion generated by the FM-to-FM conversion circuit, the light source, the photoelectric conversion circuit, and the FM demodulation circuit.
- the delay line 43 delays one output from the differential distributor 18 and outputs it to the differential combiner 40.
- the distortion generation circuit 16 outputs the distortion from the other output from the in-phase distributor 19 to the amplitude adjustment circuit 45.
- the amplitude adjustment circuit 45 and the delay adjustment circuit 46 adjust the amplitude and delay of the output from the distortion generation circuit 16 so that the distortion generated by the FM-combination conversion circuit that connects the pre-distortion circuit is minimized. And outputs it to the differential combiner 40.
- the differential synthesizer 40 differentially combines the output from the delay line 43 and the output from the delay adjustment circuit 46 with a phase that cancels the distortion of the circuit connected to the predistortion circuit 41 and outputs the result.
- the delay line 43 When the input phase of the differential synthesizer 40 for differentially synthesizing the output from the delay line 43 and the output from the delay adjustment circuit 46 is set to 0 phase and ⁇ phase, the delay line 43 When the output of the delay adjustment circuit 46 is set to the ⁇ -phase and the output of the delay adjustment circuit 46 is set to the ⁇ -phase, the phase of the electric signal at the output of the pre-distortion circuit 41 becomes the same as the phase of the electric signal at the input of the pre-distortion circuit 41.
- the distortion at the output of the circuit 41 is generated by the FM—bundling conversion circuit and the FM demodulation circuit of the distortion generation circuit 16 or generated by the FM—bundling conversion circuit, the light source, the photoelectric conversion circuit, and the FM demodulation circuit.
- the distortion has a phase opposite to that of the distortion.
- both the outputs of the in-phase distributor 19 for distributing the two electric signals are set to the ⁇ -phase, that is, the inverting type in-phase distributor, and the output from the delay line 43 and the output from the delay adjustment circuit 46 are output.
- the input phase of the differential combiner 40 that differentially synthesizes and outputs is 0 phase and ⁇ phase
- the output from the delay line 43 is ⁇ phase
- the output from the delay adjustment circuit 46 is 0 phase.
- the phase force of the electric signal at the output of the predistortion circuit 41 becomes the same as the phase of the electric signal at the input of the predistortion circuit 41, and the distortion at the output of the predistortion circuit 41 becomes the FM—conversion circuit of the distortion generation circuit 16 And the distortion generated by the FM demodulation circuit, or the distortion in the opposite phase to the distortion generated by the FM batch conversion circuit, the light source, the photoelectric conversion circuit, and the FM demodulation circuit.
- the pre-distortion circuit 41 cancels the distortion of the wide-band signal such as the video signal to be input, which is generated by the FM-block conversion circuit or the like that connects the pre-distortion circuit 41. Can be added in advance and output it can.
- both the amplitude adjustment circuit 45 and the delay adjustment circuit 46 are linear circuits, the order may be reversed.
- the amplitude adjustment circuit 45 and the delay adjustment circuit 46 are arranged on the side of the delay line 43 to adjust the amplitude and delay of the input to the differential combiner 40, and the functions of the delay line 43 and the function are degenerated. Is also good.
- the pre-distortion circuit 41 of the present embodiment the pre-distortion circuit
- the present embodiment is a pre-distortion circuit using any of the distortion generating circuits described in the first to eighth embodiments.
- FIG. 15 shows the configuration of the predistortion circuit of the present embodiment.
- a pre-distortion circuit 41 shown in FIG. 15 includes a distortion generation circuit 16, an in-phase distributor 19, a delay line 43, an amplitude adjustment circuit 45, a delay adjustment circuit 46, and an in-phase synthesizer 50.
- in-phase distributor 19 divides an input electric signal into two electric signals, and outputs the two electric signals to delay line 43 and distortion generating circuit 16.
- the distortion generating circuit 16 of the present embodiment is a distortion generating circuit of the distortion generating circuit 16 described in the first to eighth embodiments. This is a distortion generation circuit that outputs distortion that is out of phase with the distortion generated by the conversion circuit, light source, photoelectric conversion circuit, and FM demodulation circuit.
- the delay line 43 delays one output from the in-phase distributor 19 and outputs it to the in-phase combiner 50.
- the distortion generating circuit 16 generates the distortion described in the first to eighth embodiments from the other output from the in-phase distributor 19 and outputs the same to the amplitude adjusting circuit 45.
- the amplitude adjustment circuit 45 and the delay adjustment circuit 46 adjust the amplitude and delay of the output from the distortion generation circuit 16 so as to minimize the distortion generated by the FM-combined conversion circuit that connects the predistortion circuit.
- the in-phase combiner 50 combines the output from the delay line 43 and the output from the delay adjustment circuit 46 in phase with the phase for canceling the distortion of the circuit connected to the pre-distortion circuit 41 and outputs the result.
- the phase of the electric signal output from the predistortion circuit 41 is The phase of the electrical signal at the input of 41 becomes in-phase, and the distortion at the output of the pre-distortion circuit 41 is the distortion generated by the FM-to-FM conversion circuit and FM demodulation circuit of the distortion generation circuit 16 or the FM-to-FM conversion circuit , Light source, photoelectric conversion circuit, and FM demodulation circuit.
- the phases of the outputs of the in-phase distributor 19 that distributes the two electric signals are both ⁇ -phase, that is, an inverting-type in-phase distributor, and the output from the delay line 43 and the output from the delay adjustment circuit 46 are output.
- both of the input phases of the in-phase combiner 50 for in-phase synthesis and output are ⁇ -phase, that is, an inversion type in-phase combiner
- the output from the delay line 43 is the ⁇ -phase
- the output from the delay adjustment circuit 46 is Assuming that the output is 0 phase, the phase force S of the electric signal at the output of the predistortion circuit 41 and the phase of the electric signal at the input of the predistortion circuit 41 are in phase, and the distortion at the output of the predistortion circuit 41 becomes the distortion generation circuit. Distortion generated by the 16 FM-bundling conversion circuit and FM demodulation circuit, or distortion in opposite phase to the distortion generated by the FM-bundling conversion circuit, light source, photoelectric conversion circuit, and FM demodulation circuit.
- the pre-distortion circuit 41 cancels the distortion of the wide-band signal such as the video signal to be input, which is generated by the FM-block conversion circuit or the like that connects the pre-distortion circuit 41 to the wide-band signal. It is possible to add distortion of opposite phase in advance and output.
- both the amplitude adjustment circuit 45 and the delay adjustment circuit 46 are linear circuits, the order may be reversed.
- the amplitude adjustment circuit 45 and the delay adjustment circuit 46 adjust the input amplitude and delay to the in-phase synthesizer 50. Good.
- the pre-distortion circuit 41 of the present embodiment outputs a wide-band signal to which distortion in the opposite phase to the distortion generated in the FM-combination circuit and the like connected at the subsequent stage of the pre-distortion circuit 41 is added. be able to.
- This embodiment is an optical signal transmitter using the pre-distortion circuit described in Embodiments 9 to 12. More specifically, this is an optical signal transmitter using a pre-distortion circuit including the distortion generation circuit described in Embodiments 1 to 8.
- Figure 16 shows the form of this embodiment. 1 shows a configuration of an optical signal transmitter in a state.
- the optical signal transmitter 10 shown in FIG. 16 includes a section circuit 41, a second FM-bundling converter circuit 42, a light source 14 as a transmission circuit, and an optical amplifier circuit 15, and an optical signal Send
- the pre-distortion circuit 41 when a wide-band signal such as a video signal is input to the pre-distortion circuit 41, the pre-distortion circuit adds a distortion having an opposite phase to the distortion generated by the FM-combination conversion circuit and the like, Output to the second FM-bundling conversion circuit 42.
- the second FM-block converter 42 frequency-modulates the output from the pre-distortion circuit 41 and outputs the result.
- the light source 14 as a transmission circuit outputs an optical signal by intensity-modulating the output of the FM-to-conversion circuit. DFB-LD can be used as the light source. If the transmission light power from the light source is insufficient, an optical amplifier circuit 15 is added to the transmission circuit. The optical signal from the transmitting circuit is transmitted to the optical transmission line 85.
- An optical signal receiver is connected to the other end of the optical transmission line 85 to receive an optical signal.
- the predistortion circuit 41 provided in the optical signal transmitter 10 is generated by an FM-conversion conversion circuit or the like. If a wideband signal such as a video signal is frequency-demodulated by an optical signal receiver connected to the optical signal transmitter in order to add in advance reverse phase distortion that cancels out the distortion, a wideband signal with little distortion can be obtained. .
- the present embodiment is an optical signal transmitter using the distortion generation circuit described in Embodiments 1 to 8.
- FIG. 17 shows the configuration of the optical signal transmitter according to the present embodiment.
- the optical signal transmitter 10 shown in FIG. 17 includes a light source 14 as a transmission circuit, an optical amplifier circuit 15, one of the distortion generating circuits 16 described in Embodiments 1 to 8, and a second FM A circuit 42, an input terminal 51, a combiner / divider 52, a pilot signal oscillator 53, a delay line 54, a control circuit 56 as a first control circuit, and a distributor 57 as a first distributor.
- Send Send.
- pilot signal oscillator 53 outputs a pilot signal of frequency fo.
- the frequency fo is set to a frequency not used as a video channel. That is, the frequency is set to the frequency of a frequency channel in which the frequency range of the frequency-multiplexed AM video signal and QAM video signal of the input signal is not allocated. Also, 3Xfo, which is the third harmonic of the frequency fo, falls within the frequency range of the AM video signal and the QAM video signal, for example, the frequency range of the frequency-multiplexed AM video signal and QAM video signal of the input signal. It is set so that it is within 93MHz to 747MHz.
- a wideband signal such as a video signal is input to the combining / distributing device 52 via the input terminal 51.
- the combining / distributing unit 52 combines the input electric signal and the pilot signal from the pilot signal oscillator, further distributes the electric signal to two electric signals, and outputs the two electric signals to the distortion generating circuit 16 and the delay line 54.
- Delay line 54 delays the other output from combiner / distributor 52 and outputs it to differential combiner 60.
- the distortion generation circuit 16 is any of the distortion generation circuits described in the first to eighth embodiments.
- the distortion generating circuit 16 also generates a distortion in the input signal power and outputs the distortion to the distributor 57.
- Divider 57 divides the output from the distortion generating circuit into two electric signals, and outputs them to amplitude adjuster 58 and bandpass filter 62.
- the band-pass filter 62 passes an electric signal of frequency fo from one output of the divider 57 and outputs the electric signal to the level detector 63.
- the level detector 63 detects a signal level from the output of the band-pass filter 62 and outputs the signal level to the control circuit 56.
- the control circuit 56 controls the amplitude delay adjustment circuit included in the distortion generation circuit 16 so that the output from the level detector 63 is minimized.
- the control of the amplitude delay adjustment circuit of the distortion generation circuit 16 is performed by controlling the amplitude control terminal 101 of the amplitude adjustment circuit 38 of the distortion generation circuit 16 and the delay control terminal 102 of the delay adjustment circuit 39 shown in FIGS.
- an adjustment amount for controlling the amplitude amount or the delay amount is input from the control circuit 56, respectively.
- the amplitude delay adjustment circuit of the distortion generation circuit 16 is used.
- the set point of the amplitude and the set point of the delay are alternately and slightly changed, and the set point of the amplitude and the set point of the delay are controlled so that the output from the level detector 63 is minimized. If this control is executed constantly or intermittently, the component of the frequency fo is removed from the output of the distortion generation circuit 16. With such control, the distortion generating circuit can generate an optimal amount of reverse distortion that cancels out the distortion generated in the FM-to-batch conversion circuit and the like.
- the other output of distributor 57 is input to amplitude adjuster 58.
- the amplitude adjuster 58 adjusts the amplitude and outputs the result to the delay adjuster 59.
- the delay adjuster 59 adjusts the amount of delay and outputs the result to the differential synthesizer 60. Since both the amplitude adjuster 58 and the delay adjuster 59 are linear circuits, the order may be reversed.
- the amplitude adjuster 58 and the delay adjuster 59 are arranged on the side of the delay line 54 to adjust the amplitude and delay of the input to the differential synthesizer 60, and the function of the delay line 54 is degenerated. Moyore.
- the differential synthesizer 60 combines the output from the delay line 54 and the output from the delay adjuster 59 in opposite phases and outputs the combined result to the second FM-to-binary conversion circuit 42.
- the second FM-bundling conversion circuit 42 frequency-modulates the output from the differential combiner 60 and outputs it to the distributor 67.
- the divider 67 divides the output from the second FM-to-buffer conversion circuit 42 into two electric signals, and outputs the two electric signals to the light source 14 as a transmission circuit and the second FM demodulation circuit 95.
- the second FM demodulation circuit 95 outputs two frequency-demodulated electric signals from one output of the divider 67.
- the two outputs of the second FM demodulation circuit 95 are input to bandpass filters 65-1 and 65-2, respectively.
- the bandpass filter 65-1 passes an electric signal of frequency 2 Xfo
- the bandpass filter 65-2 passes an electric signal of frequency 3 Xfo.
- the output from the band-pass filters 65-1 and 65-2 is detected by the level detectors 64_1 and 64_2, respectively, and the level detectors 64_1 and 64-2 are respectively 2X fo and 3X frequency.
- the signal level of fo is detected and output to the control circuit 61.
- the control circuit 61 controls the amplitude adjustment circuit 58 and the delay adjustment circuit 59 so that the outputs from the level detectors 64-1 and 64-2 are minimized.
- the set point of the amplitude amount of the amplitude adjustment circuit 58 and the set point of the delay amount of the delay adjustment circuit 59 are alternately and slightly changed so that the output from the level detector 64-1 is minimized.
- the light source 14 as a transmission circuit outputs an optical signal after intensity modulation by the output from the distributor 67.
- DFB-LD can be used as the light source. If the transmitted light power from the light source is insufficient, an optical amplifier circuit 15 is added to the transmission circuit. The optical signal from the transmitting circuit is transmitted to the optical transmission line 85 via the output terminal 68.
- An optical signal receiver is connected to the other end of the optical transmission line 85, and the optical signal receiver receives an optical signal.
- the optical signal transmitter 10 is an optical signal receiver connected to the optical signal transmitter to add a reverse distortion that cancels the distortion generated in the FM-combination circuit or the like. When a wideband signal is demodulated, a wideband signal with little distortion can be obtained.
- the phases of the electric signal and the distortion in the distortion generating circuit 16, the combiner / distributor 52, the distributor 57, the differential combiner 60, the distributor 67, the second FM demodulation circuit 95, and the like are controlled.
- the phase is not limited to the above-mentioned phase as long as the circuit 56 and the control circuit 61 are set to perform the feedback control operation to reduce the distortion.
- the present embodiment is an optical signal transmitter using the distortion generation circuit described in Embodiments 1 to 8.
- FIG. 18 shows the configuration of the optical signal transmitter according to the present embodiment.
- An optical signal transmitter 10 shown in FIG. 18 includes a light source 14 as a transmission circuit, an optical amplifier circuit 15, one of the distortion generating circuits 16 described in the first to eighth embodiments, and a second FM A circuit 42, an input terminal 51, a combiner / divider 52, a pilot signal oscillator 53, a delay line 54, a control circuit 56 as a first control circuit, and a distributor 57 as a first distributor.
- pilot signal oscillator 53 outputs a pilot signal of frequency fo.
- the frequency fo is set to a frequency not used as a video channel. That is, the frequency is set to the frequency of a frequency channel in which the frequency range of the frequency-multiplexed AM video signal and QAM video signal of the input signal is not allocated. Also, 3Xfo, which is the third harmonic of the frequency fo, falls within the frequency range of the AM video signal and the QAM video signal, for example, the frequency range of the frequency-multiplexed AM video signal and QAM video signal of the input signal. It is set so that it is within 93MHz to 747MHz.
- a wideband signal such as a video signal is input to the combining / distributing device 52 via the input terminal 51.
- the combining / distributing unit 52 combines the input electric signal and the pilot signal from the pilot signal oscillator, further distributes the electric signal to two electric signals, and outputs the two electric signals to the distortion generating circuit 16 and the delay line 54.
- Delay line 54 delays the other output from combiner / distributor 52 and outputs it to differential combiner 60.
- the distortion generation circuit 16 is any of the distortion generation circuits described in the first to eighth embodiments.
- the distortion generating circuit 16 also generates a distortion in the input signal power and outputs the distortion to the distributor 57.
- Divider 57 divides the output from the distortion generating circuit into two electric signals, and outputs them to amplitude adjuster 58 and bandpass filter 62.
- the band-pass filter 62 passes an electric signal of frequency fo from one output of the divider 57 and outputs the electric signal to the level detector 63.
- the level detector 63 detects a signal level from the output of the band-pass filter 62 and outputs the signal level to the control circuit 56.
- the control circuit 56 controls the amplitude delay adjustment circuit included in the distortion generation circuit 16 so that the output from the level detector 63 is minimized.
- Amplitude delay adjustment of distortion generation circuit 16 The circuit is controlled by an external input to the amplitude control terminal 101 of the amplitude adjustment circuit 38 of the distortion generation circuit 16 and the delay control terminal 102 of the delay adjustment circuit 39 shown in FIGS. Enter the adjustment amount for controlling the amplitude or delay.
- the set point of the amplitude and the set point of the delay of the amplitude delay adjusting circuit of the distortion generating circuit 16 are alternately and slightly changed so that the output from the level detector 63 is minimized. And the set point of the amplitude and the set point of the delay.
- the distortion generating circuit can generate an optimal amount of reverse distortion that cancels out the distortion generated in the FM-to-batch conversion circuit and the like.
- the other output of distributor 57 is input to amplitude adjuster 58.
- the amplitude adjuster 58 adjusts the amplitude and outputs the result to the delay adjuster 59.
- the delay adjuster 59 adjusts the amount of delay and outputs the result to the differential synthesizer 60. Since both the amplitude adjuster 58 and the delay adjuster 59 are linear circuits, the order may be reversed.
- the amplitude adjuster 58 and the delay adjuster 59 are arranged on the side of the delay line 54 to adjust the amplitude and delay of the input to the differential synthesizer 60, and the function of the delay line 54 is degenerated. Moyore.
- the differential combiner 60 combines the output from the delay line 54 and the output from the delay adjuster 59 in opposite phases, and outputs the combined result to the second FM-combined conversion circuit 42.
- the second FM-converter 42 frequency-modulates the output from the differential combiner 60 and outputs it to the light source 14 as a transmission circuit.
- the light source 14 as a transmission circuit outputs an optical signal after the intensity is modulated by the output from the second FM-bundling conversion circuit 42.
- DFB-LD can be used as the light source. If the light power transmitted from the light source is insufficient, an optical amplifier circuit 15 is added to the transmission circuit.
- the optical signal from the transmitting circuit is output to the optical splitter 69, and a part is transmitted to the optical transmission line 85 via the output terminal 68.
- Another optical signal from the optical splitter 69 is input to the photoelectric conversion circuit 91 and is converted into an electric signal.
- the photoelectric conversion circuit 91 outputs the converted electric signal to the second FM demodulation circuit 95.
- the second FM demodulation circuit 95 frequency-demodulates the input electric signal and outputs two frequency-demodulated electric signals.
- Two outputs from the second FM demodulation circuit 95 are input to bandpass filters 65-1, 65-2, respectively.
- Bandpass filter 65—1 has frequency 2 X f
- the bandpass filter 65-2 passes the electric signal having a frequency of 3 ⁇ fo, while allowing the electric signal having the frequency o to pass.
- the outputs from the band-pass filters 65-1 and 65-2 are input to level detectors 64-1 and 64-2, respectively, and the level detectors 64-1 and 64-2 respectively have a frequency of 2 X fo and a frequency of 3 X fo And outputs it to the control circuit 61.
- the control circuit 61 controls the amplitude adjustment circuit 58 and the delay adjustment circuit 59 so that the output from the level detectors 64-1 and 64-2 is minimized.
- the set point of the amplitude amount of the amplitude adjustment circuit 58 and the set point of the delay amount of the delay adjustment circuit 59 are alternately and slightly changed so that the output from the level detector 64-1 is minimized.
- the set point of the amplitude amount of the amplitude adjustment circuit 58 and the set point of the delay amount of the delay adjustment circuit 59 are alternately slightly changed again.
- the set point of the amplitude amount and the set point of the delay amount are controlled so that the output from the level detector 64_2 is minimized. If this control is executed constantly or intermittently, the components of the frequency 2 Xfo and the frequency 3 Xfo in the output from the FM demodulation circuit in the optical signal receiver connected to the optical signal transmitter 10 become minimum. . By controlling in this way, it is possible to output a wideband signal such as a video signal having an optimal amount of reverse distortion that cancels out the distortion generated in the FM-to-band conversion circuit and the like. That is, automatic control can be performed so that distortion compensation by predistortion can be performed by this control method.
- An optical signal receiver is connected to the other end of the optical transmission line 85, and the optical signal is received by the optical signal reception.
- the optical signal transmitter 10 is an optical signal receiver connected to the optical signal transmitter in order to add in advance reverse distortion that cancels out distortion generated in an FM-to-conversion circuit or the like. When frequency demodulation is performed, a wideband signal with little distortion can be obtained.
- the phase is not limited to the above-described one as long as the circuit 61 is set so as to perform the feedback control operation to reduce the distortion.
- This embodiment is directed to any one of the optical signal transmitters described in Embodiments 13, 14, and 15.
- An optical signal transmission system comprising: a photoelectric conversion circuit connected to the optical signal transmitter via an optical transmission line; and an optical signal receiver having an FM demodulation circuit for frequency demodulating an output from the photoelectric conversion circuit. It is.
- FIG. 19 shows an optical signal transmitter having the pre-distortion circuit described in the above embodiment, a photoelectric conversion circuit connected to the optical signal transmitter via an optical transmission line, and the photoelectric conversion circuit.
- FIG. 2 is a diagram illustrating a configuration of an optical signal transmission system including an optical signal receiver having an FM demodulation circuit for frequency demodulating an output from a circuit.
- the optical transmission system shown in FIG. 19 includes an optical signal transmitter 10 including a second FM-to-conversion circuit 42, an optical source 14 as a transmission circuit, an optical amplifier circuit 15, and a pre-distortion circuit 41; A transmission path 85, an optical signal receiver 90 including a photoelectric conversion circuit 91 and a second FM demodulation circuit 95, a set-top box 93, and a television receiver 94 are provided.
- a distortion opposite to the distortion generated in the second FM-block conversion circuit 42 and the like is added in advance.
- the broadband signal with the reverse distortion applied passes through the second FM-to-buffer conversion circuit 42, the light source 14 as a transmission circuit, and the optical amplification circuit 15 installed as necessary, and is converted into an optical transmission line 85 as an optical signal. Sent to
- the photoelectric conversion circuit 91 of the optical receiver 90 receives the optical signal from the optical transmission line 85, and the frequency is demodulated by the second FM demodulation circuit 95. During propagation of a series of signals, distortion is added to a wideband signal to which reverse distortion has been added in advance, and the distortion is canceled.
- the optical signal transmission system described in the present embodiment can transmit a wideband signal with little distortion.
- the distortion generation circuit, the pre-distortion circuit, the optical signal transmitter, and the optical signal transmission system described in the present specification it is possible to improve distortion characteristics in transmission of a wideband signal.
- the reception quality of the video signal can be improved.
- the improvement of the distortion characteristics will increase the transmission distance and the optical branch between the optical signal transmitter and the optical signal receiver. The ratio can be increased.
- the distortion generating circuit and the pre-distortion circuit of the present invention can be applied to an optical signal transmitter, and the optical signal transmitter and the optical transmission system of the present invention have a single star (SS) network configuration of the optical transmission line.
- SS single star
- Star type topology
- PDS Passive Double Star
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- Optical Communication System (AREA)
- Amplifiers (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/559,268 US20060116143A1 (en) | 2003-08-13 | 2004-08-11 | Distortion generator circuit, pre-distortion circuit, optical signal transmitter using the same, and optical signal transmission system |
JP2005513169A JPWO2005018118A1 (ja) | 2003-08-13 | 2004-08-11 | 歪み発生回路およびプリディストーション回路、並びにこれを用いた光信号送信機および光信号伝送システム |
EP04771538A EP1655866A1 (en) | 2003-08-13 | 2004-08-11 | Distortion generator circuit, pre-distortion circuit, optical signal transmitter using the same, and optical signal transmission system |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2003-292735 | 2003-08-13 | ||
JP2003292735 | 2003-08-13 | ||
JP2003372026 | 2003-10-31 | ||
JP2003-372026 | 2003-10-31 |
Publications (1)
Publication Number | Publication Date |
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WO2005018118A1 true WO2005018118A1 (ja) | 2005-02-24 |
Family
ID=34197139
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PCT/JP2004/011553 WO2005018118A1 (ja) | 2003-08-13 | 2004-08-11 | 歪み発生回路およびプリディストーション回路、並びにこれを用いた光信号送信機および光信号伝送システム |
Country Status (4)
Country | Link |
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US (1) | US20060116143A1 (ja) |
EP (1) | EP1655866A1 (ja) |
JP (1) | JPWO2005018118A1 (ja) |
WO (1) | WO2005018118A1 (ja) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20150014444A (ko) * | 2012-04-04 | 2015-02-06 | 로슈티슬라브 보로뒤미로비취 보센코 | 채널(베리언트) 내 왜곡을 보상하는 무선 용량 신호 수신 및 송신 시스템, 방법 및 장치 |
JPWO2022024293A1 (ja) * | 2020-07-30 | 2022-02-03 | ||
WO2022144972A1 (ja) * | 2020-12-28 | 2022-07-07 | 日本電信電話株式会社 | 光送信装置及び信号検出方法 |
WO2023162207A1 (ja) * | 2022-02-28 | 2023-08-31 | 日本電信電話株式会社 | 光送信装置及び送信方法 |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
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GB2428149B (en) * | 2005-07-07 | 2009-10-28 | Agilent Technologies Inc | Multimode optical fibre communication system |
US20070249290A1 (en) * | 2006-04-24 | 2007-10-25 | Sony Ericsson Mobile Communications Ab | Adaptive pre-distortion |
FR3016262A1 (fr) * | 2014-01-07 | 2015-07-10 | Orange | Pre-distorsion d'un signal optique a sous-porteuses multiplexees en frequence |
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JP2000022641A (ja) * | 1998-07-02 | 2000-01-21 | Hitachi Cable Ltd | 広帯域fm変調器 |
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2004
- 2004-08-11 US US10/559,268 patent/US20060116143A1/en not_active Abandoned
- 2004-08-11 EP EP04771538A patent/EP1655866A1/en not_active Withdrawn
- 2004-08-11 JP JP2005513169A patent/JPWO2005018118A1/ja active Pending
- 2004-08-11 WO PCT/JP2004/011553 patent/WO2005018118A1/ja active Application Filing
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JPH09326769A (ja) * | 1996-04-05 | 1997-12-16 | Nippon Telegr & Teleph Corp <Ntt> | 変調方式変換回路及び光信号伝送装置 |
JP2000022641A (ja) * | 1998-07-02 | 2000-01-21 | Hitachi Cable Ltd | 広帯域fm変調器 |
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20150014444A (ko) * | 2012-04-04 | 2015-02-06 | 로슈티슬라브 보로뒤미로비취 보센코 | 채널(베리언트) 내 왜곡을 보상하는 무선 용량 신호 수신 및 송신 시스템, 방법 및 장치 |
KR102145969B1 (ko) | 2012-04-04 | 2020-08-20 | 로슈티슬라브 보로뒤미로비취 보센코 | 채널(베리언트) 내 왜곡을 보상하는 무선 용량 신호 수신 및 송신 시스템, 방법 및 장치 |
JPWO2022024293A1 (ja) * | 2020-07-30 | 2022-02-03 | ||
JP7328600B2 (ja) | 2020-07-30 | 2023-08-17 | 日本電信電話株式会社 | 光伝送システム及び伝送品質監視方法 |
WO2022144972A1 (ja) * | 2020-12-28 | 2022-07-07 | 日本電信電話株式会社 | 光送信装置及び信号検出方法 |
WO2023162207A1 (ja) * | 2022-02-28 | 2023-08-31 | 日本電信電話株式会社 | 光送信装置及び送信方法 |
Also Published As
Publication number | Publication date |
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EP1655866A1 (en) | 2006-05-10 |
US20060116143A1 (en) | 2006-06-01 |
JPWO2005018118A1 (ja) | 2007-10-04 |
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