CN1394400A - Method and system for transmitting signal via non-linear transmission unit - Google Patents

Method and system for transmitting signal via non-linear transmission unit Download PDF

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CN1394400A
CN1394400A CN01803228.1A CN01803228A CN1394400A CN 1394400 A CN1394400 A CN 1394400A CN 01803228 A CN01803228 A CN 01803228A CN 1394400 A CN1394400 A CN 1394400A
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signal
power
transmission unit
control signal
amplifier
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里奥尼德·鲍古德
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Nokia Oyj
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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
    • H04B10/501—Structural aspects
    • H04B10/503—Laser transmitters
    • H04B10/504—Laser transmitters using direct modulation
    • 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
    • H04B10/501—Structural aspects
    • H04B10/503—Laser transmitters
    • 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
    • H04B10/564—Power control
    • 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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  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Optical Communication System (AREA)
  • Control Of Amplification And Gain Control (AREA)
  • Amplifiers (AREA)
  • Transmitters (AREA)

Abstract

The invention relates to a system and method for transmitting a signal via a non-linear transmission unit, wherein the system aims to reduce distortion in the signal after transmission caused by intermodulation products. For achieving a decrease of intermodulation products in the output signal the system comprises a power splitter (110) for dividing the signal into a main signal and an auxiliary signal. The system further includes a power variation detector (120) for detecting power variations in said auxiliary signal and for generating a control signal representing said power variations. The system further includes a variable attenuator 130 for attenuating the power of said main signal in response to said control signal such that the said power of the main signal being input to said non-linear transmission line (200a) is kept constant if the power of the input signal exceeds a predetermined reference power value Pref. After transmission the signal is recovered by amplifying the main signal by a first variable gain amplifier (310) in response to said control signal.

Description

Method and system by the non-linear transmission unit transmission signals
Technical field
The present invention relates to a kind of method and system, this system comprises preparation unit and recovery unit, is used for by non-linear transmission unit, and especially optical fiber link comes transmission signals.
Background technology
For example from satellite or telecommunications application, can understand this system.These application require transmission unit that high dynamic range is arranged usually, preferably possess the bandwidth of several megahertzes simultaneously, because the power of typical input signal can change in the dynamic range of for example 100dB.
The traditional solution that satisfies these demands is to use optical fiber link as shown in Figure 8.This optical fiber link has low-loss, high bandwidth and lightweight advantage.According to Fig. 8, this optical fiber link comprises laser diode 850, and being used for received signal is modulated light signal with this signal transformation also.Optical fiber link comprises optical fiber 860 in addition, is used to transmit described light signal to photodiode 870, photodiode 870 from the transmission after be reduced to the signal that is input to described laser diode 850 through modulated light signal.Therefore the required high dynamic range of this transmission unit requires linear propagation characteristics.Yet optical fiber link is the nonlinear transport unit, and particularly the nonlinear characteristic by laser diode causes.Comprised in the output signal of described non-linear transmission unit in described non-linear equipment because the distortion that not wishing of causing of intermodulation occurs.
Intermodulation is meant the component of a plurality of frequency contents in the output signal of non-linear equipment; Described frequency content correspondence from wanting channel (hope) and from the signal of the adjacent channel that enters system input (undesirable) and with difference frequency (sum and differencefrequency).
In addition, intermodulation component is meant the special component in the described frequency content.
Say that exactly the secondary intermodulation component is characterised in that frequency is f1-f2 or f2-f1, and slope is 2 in the power output of described non-linear equipment and input power graph of a relation.In addition, third-order intermodulation product is characterised in that, frequency is (2f1-f2) or (2f2-f1), and wherein its slope of curve is 3 in output and input power graph of a relation.
Perhaps in optical fiber link, reduce the influence do not wish the described intermodulation component that occurs and realize that the way of high dynamic range is to use laser diode and/or the external modulator that is of high quality.Yet these two kinds of methods are all very expensive.
At US 5,321,849 and US 5,457,811 and the paper " A dynamicrange enhancement technique for fiber optic microcell radio system (dynamic range of optical fiber microcell radio system develops skill) " published of IEEE, Cheng, F., Lemson, P., Reed, J.H., Jacobs, I.Vehicular Technology Conference, 1995IEEE 45 Th, Volume 2,1995 Pages 774-778 disclose the system of the dynamic range that is used to increase transmission link respectively.The common trait of all these prior art systems is that control signal generates from transmission signals, and control signal was adjusted it before transmission signals enters non-linear transmission unit.
Summary of the invention
Come from prior art, the objective of the invention is to improve dynamic range by the system and method that is used for the non-linear transmission unit transmission signals.
Above-mentioned purpose realizes by the theme of independent claims 1 and 9 respectively.
According to claim 1, the realization of above-mentioned purpose is achieved in that power splitter is divided into main signal and auxiliary signal with signal; The variable power detector detects the variable power of described auxiliary signal and generates the control signal of the described variable power of expression; The decay power of described main signal of the described control signal that responds variable attenuator makes the power of the described main signal that is input to described non-linear transmission unit (200a) keep constant; And for recovering this signal once more, by amplifier amplify main signal after described non-linear transmission unit transmission with response also through control signals transmitted.
Because by variable attenuator output and the main signal power that is input to described non-linear transmission unit is constant, so also be constant by the baseband signal of described transmission unit output and the ratio of intermodulation component.Like this, by reducing second order and third-order intermodulation product, the system that is proposed makes is enough to have the very signal of high dynamic range by the non-linear transmission unit transmission.
Therefore, this system particularly linearity of transmission unit is improved, and has reduced the distortion of this system output signal simultaneously.Can use the transmission unit that linearity improves, transmission unit substitutes costliness cheaply.
According to first embodiment, described system comprises comparator, is used for the power and the predetermined reference power value of described auxiliary signal are made comparisons, and generates the control signal of the described comparative result of expression.Described comparator is more convenient for detecting described variable power.
More advantageously, this system comprises second amplifier, to through described main transmission equipment or described other transmission unit control signals transmitted, amplifies before being sent to first amplifier.Control signal with the control signal that the be input to described variable attenuator identical mode of described second amplifier by being used for controlled first amplifier, the loss of compensating signal in described other transmission units.Can guarantee that by this method the decay that described controlled first amplifier causes is accurately reduced.
According to another embodiment, system comprises that to be used for transmission of control signals better to another transmission unit of first amplifier.Described another transmission unit is not required high linear characteristic, consequently, can use low-cost element, particularly digital laser diode or cheap LED cheaply.This system is based on such theory, for most of cellular protocols such as Wideband Code Division Multiple Access (WCDMA) (W-CDMA) or global system for mobile communications (GSM) transmission, the variation of I/O power occurs in one slowly in the markers, therefore, does not need phase adjustment device.
Perhaps, control signal is not by described other transmission line transmission, but employing wavelength division multiplexing (WDM) technology is transmitted by the identical traffic circuit with the main signal use.For realizing this technology, the non-linear transmission unit of system comprises: the laser diode that is used for main signal is converted to first light signal; Be used for control signal is converted to the light-emitting diode of second light signal; Be used for generating the multiplexer of multiplexed signals by multiplexing first and second light signals; Be used for transmitting the optical fiber of described multiplexed signals to demodulation multiplexer from described multiplexer, wherein the effect of demodulation multiplexer is from through the multiplexed signals of described Optical Fiber Transmission, reduce described first light signal and described second light signal, and export the photodiode of these light signals to two separation respectively, with reduction main signal and control signal.
This purpose also can realize by method according to Claim 8.The advantage of the corresponding above mentioned system of the advantage of described method.
Advantageously, the adding of control signal only makes that the power of main signal just remained constant when power at input signal surpassed described predetermined reference power value.
In addition, by using preparation unit in the system of mentioning in the above, and comprise power splitter, variable power detector and variable attenuator can be realized this purpose.Preparation unit can advantageously be guaranteed to generate main signal from input signal, if the power of input signal surpasses predetermined reference power value P like this Ref, the power of main signal remains constant behind a certain setting power.Main signal is transmitted by described nonlinear transport circuit.
In addition, by using recovery unit in the above in the system of mentioning and comprising that amplifier can realize this purpose.Described recovery unit helps restoring signal correctly from the main signal of transmission.
Description of drawings
Following accompanying drawing has explanation, wherein
Fig. 1 is the system block diagram according to first embodiment of the invention;
Fig. 2 is second embodiment of the transmission unit of system shown in Figure 1;
Fig. 3 is the schematic diagram of the power ratio of baseband signal composition and third-order intermodulation product in the output signal of non-linear equipment;
Fig. 4 is the under powered schematic diagram of third-order intermodulation product in optical fiber link according to the present invention;
Fig. 5 is the graph of a relation of power output and power input, has illustrated in typical nonlinear equipment response input power, the power of the third-order intermodulation product in the output signal;
Fig. 6 is the graph of a relation of power output and power input, has illustrated for first group of analog parameter the reduction of third-order intermodulation product in according to the output signal of system of the present invention;
Fig. 7 is the graph of a relation of power output and input power, has illustrated for second group of analog parameter the reduction of the third-order intermodulation product of realizing for system according to the present invention;
Fig. 8 is the block diagram as the optical fiber link of the embodiment of technical known nonlinear transport equipment; And
Fig. 9 is to the improvement according to the block diagram of Fig. 1.
Embodiment
Describe the present invention in detail below with reference to Fig. 1 to 7.
Fig. 1 is first embodiment according to system of the present invention.This system comprises preparation unit 100, transmission unit 200 and recovery unit 300.
Preparation unit 100 comprises power splitter 110, is used for signal, hereinafter claims input signal, is divided into main signal and auxiliary signal, and wherein the ratio of main signal power and auxiliary signal power is for example 1: 10.Auxiliary signal is sent to variable power detector 120, is used for detecting in the variable power of described auxiliary signal and the control signal that generates the described variable power of expression.For realizing this function, variable power detector 120 comprises power detector 124, leaches power signal from described auxiliary signal, and exports described power signal to the comparator 126 that is also included within the variable power detector 120.Described comparator 126 is with the power of described power signal and by reference voltage V RefThe predetermined reference power value P of expression RefMake comparisons.Comparator 126 detects the variable power of auxiliary signal and generates control signal and represents described variable power in this way.
Described control signal is sent to variable attenuator 130, is used to respond the decay power of described main signal of described control signal.
By presenting control signal to variable attenuator 130, when preparation unit 100 can guarantee that the power P 1 when auxiliary signal surpasses described reference power value, the power of main signal kept constant.
According to Fig. 1, main signal and control signal promptly, are passed through independently transmission unit 200a and transmission unit 200b respectively by the transmission unit 200 of first embodiment, are sent to recovery unit 300 from preparation unit 100.Transmission unit 200a and 200b are for example technical known optical fiber links, and as top with reference to as described in the figure 8.Suppose special because the nonlinear characteristic of laser diode 250, the transmission unit 200a that is used to transmit main signal is in particular non-linear transmission unit.
Laser diode 250 can be the laser diode of any kind, does not have the special linear requirement at application-specific; Therefore, it can be cheap laser diode, as is generally used for the fabry-Perot laser diode of digital application (digital laser), or high linear expensive laser diode, as is generally used for the DFB laser diode of simulation application.Yet what should emphasize once more is, supposes that the linearity at the transmission unit 200a laser diode 250 that is used for transmitting main signal is not enough to satisfy the needs of application-specific.
In addition, the linearity that is used for the second transmission unit 200b from preparation unit 100 transmission of control signals to recovery unit 300 requires also very low, therefore, the laser diode among the optical fiber link 200b can replace or only replace with LED with cheap fabry-Perot laser diode.
When the power of input signal surpasses P RefThe time, have the main signal of firm power, after non-linear transmission unit 200a transmission, the amplifier 310 that is resumed in the unit 300 receives and amplification.The amplification of described amplifier 310, thereby the amplification of the main signal that receives are subjected to be sent to by the described second transmission unit 200b control of the control signal of recovery unit.
Transmission unit 200b or recovery unit 300 preferably include the second amplifier 200c, are used for amplifying described control signal before described control signal is transmitted the back and is being input to described controlled first amplifier 310.The gain of the preferred described second amplifier 200c of adjustment is to compensate the loss in the described second transmission unit 200b.In that case, it is identical with the control signal that is applied to controlled first amplifier 310 to be applied to variable attenuator 130.At that rate, according to system of the present invention, more precisely, controlled first order amplifier 310 is suitable at its output main signal being reverted to its initial value, refers to input signal here.In other words, controlled first order amplifier 310 is suitable for compensating the decay that is provided by described variable attenuator 130.
In a word, the gain G of the second amplifier 200c 2Can be calculated as: G 2 = α 1 · L 2 α 2 - - - ( 1 )
In the formula:
L2: represent the loss in second optical fiber link;
A1: the proportionality coefficient that is variable attenuator; And
A2: the proportionality coefficient that is variable amplifier.
Fig. 2 is second embodiment according to the transmission unit of system of the present invention shown in Figure 1.According to Fig. 2, main signal and control signal all pass through to adopt same optical fiber 260 transmission of WDM technology.
For achieving this end, in second embodiment 200 ', transmission unit is embodied as optical fiber link, and it comprises that laser diode 250 is converted into first light signal with main signal, comprises light-emitting diode 250 ' control signal is converted to second light signal simultaneously.Described first and second light signals all are sent to multiplexer 210, generate multiplexed signals by multiplexing described two light signals.This multiplexed signals also is a light signal, and it is exported from described multiplexer, is transferred to demodulation multiplexer 220 through optical fiber 260.The effect of this demodulation multiplexer 220 is, through the multiplexed signals of transmission, isolate described first and second light signals from described, and with isolated light signal output to the photodiode 270,270 of two separation ', these two diodes are converted to main signal and control signal respectively with light signal.
Control signal was preferably amplified by the second amplifier 200c before being sent to first order amplifier 310.For understanding the operation of described second level amplifier 200c, referring to the description of Fig. 1.
Mention above, in system according to the present invention,, when the power of input signal surpasses predetermined reference power value Pref, have firm power through main signal according to the described non-linear transmission unit transmission of first and second embodiment.
In that one of them carries out between transmission period by described transmission unit 200a or 200 ', the constant of main signal power makes main signal when described linear transfer unit 200a or 200 ' exports, and third-order intermodulation product IM3 has wherein reduced.Therefore, after recovering from described main signal, promptly after described controlled first amplifier 310 outputs by recovery unit 300, the IM3 component in the input signal has also reduced.Because the reduction of described IM3 component, the main signal distortion that is caused by the non-linear transmission unit 200a or 200 ' of first or second embodiment has also reduced, and in this way, linear degree, or in other words, the high dynamic range of system is achieved.Therefore, also can be counted as linearizer according to system of the present invention.
To prove described purport of the present invention in detail below:
Mention that with reference to figure 8 and 9 intermodulation component can appear in any non-linear equipment as top.For the system according to Fig. 1 or Fig. 2, variable attenuator should think not produce the passive device of any intermodulation component.Yet, being further confirmation, transmission unit 200a and controlled first amplifier 310 all should think to produce respectively the non-linear equipment of intermodulation component in their output signal.
Therefore, when the whole system of considering according to Fig. 1 or 2, suppose that intermodulation component composition that the main signal by controlled first amplifier output comprises can think the stack of the intermodulation component that self causes by the first transmission unit 200a with by controlled first amplifier 310.Yet according to the present invention, the intermodulation component that is generated by described non-linear transmission unit 200a reduces, and the intermodulation component in the output signal of controlled like this first amplifier has also reduced.
Explain this design below with reference to Fig. 3 to 7.
Fig. 3 illustrated in the output signal of typical nonlinear equipment, for specific input power P1, and the ratio of baseband signal composition power and third-order intermodulation product power.
For example, the output signal of this non-linear equipment also comprises third-order intermodulation product IM3 except comprising the baseband signal composition.Suppose that the signal that is input to described equipment has input power P1=-40dBm, the power P _ fund of the baseband signal composition in the output signal is-25dBm that the power P _ IM3 of the IM3 in the output signal is about-110dBm.
Yet as can be seen from Figure 3, in the output signal of described system, the curve of baseband signal composition P_fund and third-order intermodulation product P_IM3 has Different Slope in power output and input power graph of relation; Exactly, in described curve chart, the slope of baseband signal composition is 1, and the slope of third-order intermodulation product is 3.
Therefore, for each non-linear equipment, the crosspoint definable IM3 capture point separately of curve by baseband signal composition P_fund and the curve of third-order intermodulation product P_IM3.Each crosspoint also can be by power output and the input power graph of a relation according to Fig. 3, i.e. its output defines with the coordinate in input crosspoint, three rank.
With reference to Fig. 1 and 2, the transmission characteristic of non-linear transmission unit 200a and non-linear controlled first amplifier 310 can be described by the curve chart separately according to Fig. 3 respectively.
Only the third-order intermodulation product IM3 of non-linear transmission unit 200a and controlled first amplifier 310 is discussed below, and its baseband signal composition is not discussed, because baseband signal is recovered by variable gain amplifier AMP1 310 according to control signal.
Non-linear transmission unit 200a, (output) power of the third-order intermodulation product P_IM3 of optical fiber link fol exactly, can calculate like this:
P_IM3 fol＝3xP out-2xOIP3 fol (2)
In the formula
P Out: the power of representing the output signal of described non-linear transmission unit 200a; And
OIP3 Fol: the power output of representing the TOI point of described non-linear transmission unit 200a.
Formula (2) provides the simple computation method of the power of third-order intermodulation product, because OIP3 FolUsually do not rely on gain.
At the power P _ IM3 shown in Fig. 4 FolBe schematically, promptly without any conversion relation.
According to Fig. 4, at P_IM3 FolCurve in two zones can distinguish and be:
1. for input power P InLess than reference power P Ref, referring to Fig. 1 explanation, for example P Ref=-45dBm, expression P_IM3 FolCurve illustrated that slope is 3 common characteristics.
2. for input power P InGreater than reference power P Ref=-45dBm, P_IM3 FolCurve is a level, this means P_IM3 and P InIrrelevant.
P In＞P RefThe time IM3 power constant mean that IM3 reduces in the output signal of described optical fiber link.This is because the constant that is input to according to the main signal power in the optical fiber link of the present invention causes, referring to the explanation of Fig. 1 and 2.
With P_IM3 discussed above FolOn the contrary, the P_IM3 of controlled first amplifier 310 FolCan be calculated as follows:
PIM3 AMP1＝3xP out_AMP1-2xOIP3 AMP1 (3)
In the formula
PIM3 AMP1: the power that is illustrated in third-order intermodulation product in the output signal of the first controlled amplifier 310;
P Out_AMP1: the power output of representing baseband signal composition in the output signal of first amplifier 310;
OIP3 AMP1: the power output component of representing the TOI point of first amplifier 310.
Can obviously find out from formula 3, as parameter OIP3 AMP1When high, nonlinear amplifier, for example the power of the IM3 in the output signal of first amplifier 310 is little.
Be correct recovery amplitude, the gain G of variable optical fiber link TOTALShould be constant.It can calculate according to following formula:
G TOTAL＝-L att+G link+G AMP1(4)
In the formula: L Att: the attenuator loss of representing with dB
G Link: first link gain of representing with dB
G AMP1: the AMP1 power gain of representing with dB.
Because from OPAMP 126 feedbacks according to Fig. 1, L AttDepend on input power P In, and can be described as:
L att＝L 0+(P in-P ref)+a1 (5)
In the formula: L 0: the initial decay so that dB represents reaches
A1: the proportionality coefficient of variable attenuator.
G LinkDo not rely on P InUp to saturation condition, and can be taken as constant.
G AMP1Depend on input power P In:
G AMP1＝G 0+(P in-P ref)+a2+G link2+G AMP2 (6)
In the formula: G 0: the initial power gain of AMP1,
A2: the proportionality factor of variable amplifier,
G Link2And G AMP2: be respectively second link and second Amplifier Gain.
Recover G for amplitude AMP1Should equal L Att, or have the P of being independent of InDifferent constants.
Fig. 5 illustrated at nonlinear amplifier, first amplifier 310 itself for example, output signal in the characteristic of IM3.Clearly, according to equation 3 third-order intermodulation product P_IM3 AMP1Power slope be 3.
As top pointed, at power P IM3 according to the third-order intermodulation product in the output signal of the controlled first order amplifier 310 of Fig. 1 TOTAL, can think by each non-linear transmission unit 200a i.e. optical fiber link, the third-order intermodulation product P_IM3 that causes FolWith the third-order intermodulation product P_IM3 that itself causes by first amplifier 310 AMP1Stack.Therefore, P_IM3 TOTALCan be calculated as:
P_IM3 TOTAL＝P_IM3 fol+P_IM3 AMP1 (7)
Fig. 6 has illustrated for the result according to the described stack of system of Fig. 1 or 2.Specifically, it has been illustrated for the system according to Fig. 1 or 2, has been the power P _ IM3 of the power third-order intermodulation product of response input signal in the output signal of first amplifier 310 AMP1
Clearly, with input power less than reference power P RefThe time slope compare, input power surpasses reference power P RefP_IM3 during=-45dBm TOTALSlope of a curve is less.The reducing of slope means when input power and surpasses P RefDuring=-45dBm, the power of total third-order intermodulation product has reduced in the output signal of first amplifier 310.Described reduction its power owing to being imported into non-linear transmission unit 200a when main signal is that constant causes, referring to Fig. 4 explanation.
Also show according to the simulation of Fig. 6 in the output signal of first order amplifier 310 and remove P_IM3 TOTALOuter baseband signal component P_fund, this simulation utilizes following parameter to carry out:
The optical fiber link gain G TOTAL=-15dB;
The power output OIP3 of the TOI point of optical fiber link Fol=20dBm; And
The power output OIP3 of the TOI point of first amplifier AMP1=100dBm (the first desirable amplifier).
From the analog result of Fig. 6 as can be seen, in the output signal of first amplifier 310, the ratio of baseband signal and the power of total third-order intermodulation product is at input power P InDuring＞-45dBm constant (curve of the curve of baseband signal composition and IM3 component is substantially parallel).
Because be responding power greater than the input signal of-45dBm, the IM3 in the system output signal reduces, therefore the distortion of the described output signal that is caused by described IM3 reduces (comparing with continuous slope 3 in whole input power range).Therefore, system according to the present invention resembles works the linear circuit, and can transmit the signal with high dynamic range.
Fig. 7 shows another analog result according to the system of Fig. 1 or 2 at last, wherein is provided with following parameter:
The optical fiber link gain G TOTAL=-15dB;
OIP3 Fol=20dBm, and
OIP3 AMP1＝35dBm。
Different with Fig. 6 is that according to Fig. 7 simulation is non-ideal amplifier 310.In the case, being connected in series of the TOI of whole system point, particularly non-linear transmission unit 200a and first amplifier 310 as can be seen in Fig. 7.Obviously, surpass reference power P in input power RefDuring=-45dBm, system's final output signal, promptly the IM3 in the output signal of amplifier 310 has reduced about 20dB.The power output OIP3 of the TOI point of whole system as a result TOTAL, promptly according to the OIP3 of the linear circuit of Fig. 1 or 2 TOTALIncreased about 10dB.
Therefore, Fig. 7 has illustrated in real system according to the present invention, also can realize third-order intermodulation product and the minimizing of the distortion in the output signal after transmitting thus.
Fig. 9 has illustrated according to the improvement of the system of Fig. 1.Except comprising multiplexer 127 in addition, the complete characteristic shown in Fig. 9 system is all corresponding with the characteristic of Fig. 1.Multiplexer 127 has reference voltage as its first input signal, and the signal that is produced by base band (BB) processor is as its second input signal.Signal SBB is generated in the usual way by baseband processor.
Preferably according to signal to noise ratio (SNR BPEC) needs reference power P is set Ref
If described system is used as the down link of base station, minimum P RefCan be calculated as:
P ref＝SNR BPEC+NF link+N floor+10*log(BW)
In the formula:
NF Link--the noise factor of the optical fiber link represented with dB
N Floor--the transmitter noise radix of representing with dBm/Hz
The frequency transmission signal bandwidth that BW--represents with Hz
If described system is used for ul transmissions, P RefSetting just more complicated.In this case, in identical frequency band, undesired signal may be stronger than the signal of wanting.Therefore should P be set according to the SNR of desired signal Ref, rather than P is set according to the SNR of total input signal RefLike that just need be from the response of base band (BB) processor, this is to be provided by the multiplexer among Fig. 9 127.

Claims (12)

1. one kind is used for by non-linear transmission unit (200a, 200 '), and particularly optical fiber link comes the system of transmission signals, the system is characterized in that:
Power splitter (110) is used for signal is divided into main signal and auxiliary signal;
Variable power detector (120) is used to detect the variable power of described auxiliary signal, and generates the control signal of the described variable power of expression;
Variable attenuator (130) is used to respond the described control signal power of described main signal of decaying, and remains constant so that be input to the power of the described main signal in the described non-linear transmission unit (200a, 200 '); And
Amplifier (310) is used to respond the described control signal that also is transmitted, and amplifies through the main signal after described non-linear transmission unit (200a, the 200 ') transmission, so that recover this signal once more.
2. according to the system of claim 1, it is characterized in that, variable power detector (120) comprises comparator (126), is used for the power and predetermined reference power value (Pref) of more described auxiliary signal, and generates the described control signal of the described comparative result of expression.
3. according to the system of claim 2, it is characterized in that control signal embodies by this way, promptly only when the power of input signal surpasses described predetermined reference power value, keeping the power of main signal is constant.
4. according to the system of claim 2, it is characterized in that variable power detector (120) also comprises power detector (124), be used for being input to described comparator (126) before, it is carried out filtering in auxiliary signal.
5. according to the system of claim 1, it is characterized in that second amplifier (200c) is used in described control signal after transmitting and being input to amplifier (310) before it being amplified.
6. according to the system of claim 1, it is characterized in that this system also comprises another transmission unit (200b), be used for transmission of control signals to amplifier (310).
7. according to the system of claim 1, it is characterized in that non-linear transmission unit (200 ') comprising:
Laser diode (250) is used for main signal is converted to first light signal;
Luminaire (250 ') is used for control signal is converted to second light signal;
Multiplexer (210) is used for by multiplexing first and second light signals, produces multiplexed signals;
Optical fiber (260), be used for described multiplexed signals is sent to demodulation multiplexer (220) from described multiplexer (210), wherein demodulation multiplexer (220) is used for from recovering described first light signal and described second light signal by the described multiplexed signals through transmission after described optical fiber (260) transmission, and the photodiode (270,270 ') of exporting described first and second light signals to two separation respectively.
8. according to the system of claim 2, it is characterized in that the reference power value (P that this is predetermined Ref) from multiplexing reference voltage (V Ref) with from output in the multiplexer (127) of the response signal of broadband processor.
9. one kind is used for the method for coming transmission signals by non-linear transmission unit (200a), particularly optical fiber link, the method is characterized in that step:
Signal is divided into main signal and auxiliary signal;
Detect the variable power of described auxiliary signal and generate the control signal of representing described variable power;
Respond the described control signal power of described main signal of decaying, remain constant so that be input to the power of the described main signal of described non-linear transmission unit (200a);
By described non-linear transmission unit (200a) transmission main signal; And
By amplifying main signal, from through the main signal of transmission, recovering this signal, to respond the described control signal that also is transmitted through transmission.
10. method according to Claim 8 is characterized in that, control signal embodies by this way, and promptly only when the power of input signal surpasses predetermined reference power value, the power that enters into the main signal of transmission unit (200a) remains constant.
11. the preparation unit as the part of the system as claimed in claim 1 (100) is characterized in that:
Power splitter (110), variable power detector (120) and variable attenuator (130).
12. the recovery unit as the part of the system as claimed in claim 1 (300) is characterized in that:
Variable gain amplifier (310).
CN01803228.1A 2000-09-21 2001-09-21 Method and system for transmitting signal via non-linear transmission unit Pending CN1394400A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EPPCT/EP00/09264 2000-09-21
PCT/EP2000/009264 WO2002025843A1 (en) 2000-09-21 2000-09-21 Method and system for transmitting a signal via a non-linear transmission unit

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CN1394400A true CN1394400A (en) 2003-01-29

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CN01803228.1A Pending CN1394400A (en) 2000-09-21 2001-09-21 Method and system for transmitting signal via non-linear transmission unit

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JP (1) JP2004509554A (en)
CN (1) CN1394400A (en)
AU (2) AU2000279058A1 (en)
BR (1) BR0107239A (en)
WO (2) WO2002025843A1 (en)

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Publication number Priority date Publication date Assignee Title
US7657189B2 (en) * 2004-12-17 2010-02-02 Raytheon Company Optical link

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2610667B2 (en) * 1988-11-25 1997-05-14 住友電気工業株式会社 Optical communication system
US5321849A (en) * 1991-05-22 1994-06-14 Southwestern Bell Technology Resources, Inc. System for controlling signal level at both ends of a transmission link based on a detected valve
JPH05291981A (en) * 1992-04-15 1993-11-05 Sony Corp Digital signal processor
JP3183417B2 (en) * 1992-04-17 2001-07-09 ソニー株式会社 A / D converter
JP3202867B2 (en) * 1993-09-07 2001-08-27 松下電器産業株式会社 Signal compression circuit and optical transmitter
JP4405598B2 (en) * 1996-07-09 2010-01-27 富士通株式会社 Signal light output device and optical transmission system having signal light output device
US5793782A (en) * 1996-11-15 1998-08-11 Ericsson, Inc. Linearized external modulator transmitter with improved dynamic range
JPH11122190A (en) * 1997-10-15 1999-04-30 Kokusai Electric Co Ltd Optical transmitter
JP3618208B2 (en) * 1997-11-12 2005-02-09 パイオニア株式会社 Noise reduction device

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WO2002025843A1 (en) 2002-03-28
WO2002025844A1 (en) 2002-03-28
BR0107239A (en) 2002-07-09
JP2004509554A (en) 2004-03-25
AU2001287745A1 (en) 2002-04-02
AU2000279058A1 (en) 2002-04-02

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