CN1159868C - Control method and device for stabilizing output level of light receiver - Google Patents
Control method and device for stabilizing output level of light receiver Download PDFInfo
- Publication number
- CN1159868C CN1159868C CNB991172787A CN99117278A CN1159868C CN 1159868 C CN1159868 C CN 1159868C CN B991172787 A CNB991172787 A CN B991172787A CN 99117278 A CN99117278 A CN 99117278A CN 1159868 C CN1159868 C CN 1159868C
- Authority
- CN
- China
- Prior art keywords
- receiver
- output level
- control signal
- optical
- signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Optical Communication System (AREA)
Abstract
The present invention relates to a method for controlling the stability of the output level of an optical receiver, which controls the stability of the output level by detecting optical power and modulation degree. A receiver for implementing the method comprises an optical receiving module, a fixed gain processing circuit, a variable gain processing circuit, a control signal generating circuit, a DC optical detector, a coupler and a network management signal processing unit, wherein the optical power from the DC optical detector and the modulation degree from the coupler are synthesized by the network management signal processing unit for generating signals for sending in the control signal generating circuit; then, a signal is generated for controlling the gain variation of the variable gain processing circuit for keeping the stability of the output level. The present invention does not need a high frequency processing circuit, and has high control precision and good stability.
Description
The present invention relates to broadcasting and TV and telecommunications etc. and use the field of analog optical transmission system.Particularly, adopt in the optical transmission system of analogue modulation system at cable TV and other, change, import under the situations such as optical power change of optical receiver in the transmitter modulation degree, receiver keeps stabilizing output level.
Existing such as simulated light transmission fields such as Optical CATV in, existing most of optical receivers do not have the function of automatic control stabilizing output level, but by manually or by the network management system Long-distance Control realizing the stable of output level.All by manually finishing, the total signal gain of receiver just can not change once definite said process, and the receiver output level will change owing to variation, the transmitter modulation degree of received optical power and the variation of link attenuation changes.Like this, the receiver output level is unsettled, and receiver does not have automatic output level controlled function in other words.
For having AGC (automatic gain control: the level equalization control method of function AUTO GAIN CONTROL), the 82nd page and 182 pages has comparatively detailed introduction in " " cable TV technology "; Wang Xisheng etc. write, Electronic Industry Press, 1997 " book.As shown in Figure 1, existing optical receiver, comprise Optical Receivers 1, fixed gain rf processing circuitry 2, variable gain treatment circuit 3 (being AGC amplifier or electrically controlled attenuator), radio frequency testing circuit 4, control signal generation circuit 5, direct current optical detecting unit 6 and webmaster signal processing unit 7, also have coupler 8; Its working method is: coupler 8 is coupled out sub-fraction with output level 9, the signal that is coupled out is carried out level detection (level detection control mode) or pilot detection (pilot channel system) by radio frequency testing circuit 4, produce control signal with the signal that detects output by control signal generation circuit 5, control variable gain treatment circuit 3 is realized the stable of output level 9.Control signal generation circuit 5 is also delivered to webmaster signal processing unit 7 with the control signal that produces simultaneously, so that whether the control signal of the operating state of supervision control signal generation circuit 5 and generation is normal.
The main application of the direct current optical detecting unit 6 among Fig. 1 is, for webmaster signal processing unit 7 provides the luminous power of receiver, produces alarm when luminous power surpasses certain scope, because the system transmissions index just can reach requirement when having only luminous power in certain scope.It is the size of knowing received optical power intuitively only that existing receiver luminous power detects, and perhaps informs by webmaster whether each the acceptance point received optical power in the network is normal; Stablizing of 7 pairs of control of direct current optical detecting unit 6 and webmaster signal processing unit output level 9 is also inoperative.The radiofrequency signal that coupler 8 is coupled out also has part to deliver to the demodulator circuit of webmaster signal processing circuit 7, and the user command that front end is sent here, the information such as operating state of transmitter are told receiver.
So in the prior art, in order to solve the problem of receiver stabilizing output level, concluding has three kinds of solutions: level detection control, pilot tone control and manual (machinery or electricity are transferred) control method.
For the level detection control method, require receiver at first the signal level of output to be carried out power detection and produce control signal, go control to have AGC amplifier or electrically controlled attenuator with control signal, change guaranteeing the stable of output level by Amplifier Gain variation or electrically controlled attenuator attenuation.The level detection feedback controling mode has its advantage, but several weak points are also arranged: need high-frequency wideband power detection device, increase the complexity and the cost of hardware; Because detector diode is to the responsiveness difference of different frequency bands, therefore same level will produce different power-level detectors in different frequency ranges, has very big error.This control system can only keep power level total in the whole frequency band to stablize, and can not guarantee the stabilization of level of single channel.For existing in the environment such as burst noise, the electrical level detection portion of this control system will be the very high noise mistake of the amplitude of burst as signal power, and then thinks that level is too high by mistake and produce the level that action reduces signal; In addition, be subjected to average power detection to be subjected to the device performance limitations, control precision is limited.
Pilot channel system is reasonable solution, its essence is by detect the high stable signal that sends by front end at receiver side, judge the variation of transmission channel signal gain and produce feedback control signal according to the variation of the signal that receives and go gain-variable part in the control channel, realize the stable of whole communication channel signal gain according to the variation of channel signal gain.But the pilot tone control system need increase pilot tone equipment at front end, and receiving terminal increases the pilot tone treatment facility, and this has just increased the complexity of network, reduces reliability and has increased the cost of network.
Manual adjusting style can be used at the beginning of the equipment network the independent adjustment to each acceptance point of whole network.This mode is slow to the signal reacting condition.Usually, then adopt manual mode to deal with problems, can not meet the demands at all in many occasions causing improperly consequence to find.
In reverse return system, above-mentioned three kinds of methods all have significant limitation: level detection is subjected to the restriction of burst noise, and returns the different application that also limit this kind method of modulation degree of image and digital signal in the back emitted machine; The pilot tone mode is reality not; Big and difficult realization of manual adjustment workload.Above-mentioned drawbacks limit the use in reverse return system, particularly during large-scale network-estabilishing.
First purpose of the present invention is to propose a kind of method of utilizing optical power signals receiver control stabilizing output level.Adopt the present invention, on existing network, receiver, increase any complicated hardware equipment hardly and just can realize the stable of output level.
Second purpose of the present invention provides a kind of analog optical receiver that adopts above-mentioned stabilizing output level control method.
For realizing first goal of the invention, the step of analog optical receiver stabilizing output level control method is as follows:
1) size of the received optical power of detection optical receiver;
2) judge the variation of output level of light receiver according to the size of received optical power;
3) produce control signal according to above-mentioned situation of change the output level of receiver is changed in the opposite direction, to obtain stable output; Return step 1).
Its feature also is, in above-mentioned steps 1) in except the changing factor of considering luminous power, also consider the information transfer system or the user command information of transmitter, above-mentioned steps 2) produce the output level that control signal makes receiver after the integrated treatment and keep stable.
For realizing second goal of the invention, the analog optical receiver of stabilizing output level is characterized in that comprising:
Optical Receivers is used for opto-electronic conversion;
The fixed gain rf processing circuitry is used for the amplification of described Optical Receivers electrical signal converted, decay etc.;
The variable gain treatment circuit, the signal amplification that is used for described fixed gain rf processing circuitry is sent into, decay etc. come the variation of ride gain by a control signal;
Control signal generation circuit is used to produce the control signal of described variable gain treatment circuit needs;
The direct current optical detecting unit is used to detect the luminous power of described Optical Receivers, and sends into described control signal generation circuit.
Its feature also is, also comprises coupler and webmaster signal processing unit;
Described coupler is used for being coupled out information transfer system or user command information is given the webmaster signal processing unit from the output signal of variable gain treatment circuit; Described direct current optical detecting unit is also sent into optical power signals the webmaster signal processing unit; Described webmaster signal processing unit is used for integrated treatment received optical power, the requirement of percentage modulation user command, sends into described control signal generation circuit to produce control signal.
After adopting the present invention, concluding has following advantage:
1) can when changing, channel number guarantee each channel signals stabilization of level that receiver is exported.Because the channel number of multichannel carrier modulation transmission system such as present Optical Fiber CATV System often changes, adopt the system of level detection control mode actual output level to be reduced or increase, can not keep the stable of every channel level owing to the increase or the minimizing of channel number.And every channel stabilizing output level is very important under many circumstances.Use the present invention, owing to use the direct current light signal as control information, so the variation of channel number can be to any influence of stable generation of output level.Situation is similar to the variation of channel number in the serious system of noise.
2) the stable influence that can not be subjected to the power of burst noise of signal level.The present invention has more effect in the backlight transmission system, at first the influence of burst noise is avoided in the detection of luminous power; Secondly as long as the relation that the modulation degree of image in the transmitter and digital information is maintained fixed can not considered this problem in receiver, only the receiver output level need be adjusted to some fixed values and get final product.The use of the present invention in oppositely returning is actually luminous power as the pilot signal on the light path.Oppositely the received optical power of receiver alters a great deal in addition, guarantees the necessary property of receiver stabilizing output level.Adopt luminous power to detect the control radio frequency level and stablize a kind of reasonable method.
3) can be used to transmit any high frequency and the analog signal optical transmission system of bandwidth arbitrarily.As the application in hyperfrequencies such as Transmission Microwave and ultra-broadband signal optical link, because detecting control mode, luminous power do not need radio frequency or microwave signal power detection or pilot tone detection, therefore control mode and precision are not subjected to the restriction of factors such as transmission bandwidth and frequency, therefore can be used for the analog optical transmission system receiver output level control in the various fields from the arrowband to the broadband, from the low frequency to the microwave.
4) luminous power detection feedback controling mode is very simple, increases hardware investment and complexity hardly; And can carry out FEEDBACK CONTROL timely and accurately to the variation of signal level, realize the stable of output level of light receiver under the various situations.
Below by specific embodiment and in conjunction with the accompanying drawings to the description in further detail of the present invention's do.
Fig. 1 is the functional-block diagram that existing optical receiver utilizes level detection control stabilizing output level;
Fig. 2 is that optical receiver of the present invention utilizes luminous power to detect the functional-block diagram of control stabilizing output level;
Fig. 3 is the application examples of the present invention in the bi-directional light transmissions pass structure.
Figure 1 shows that existing optical receiver, monitor output level immediately and make output level keep stable by feedback control system by the radio frequency testing circuit.
The output level of receiver is mainly by the insertion loss decision of Amplifier Gain and each parts in the resistance of the responsiveness of the photodiode of the percentage modulation receiver of received optical power, transmitter, load resistance, the receiver.The output level of above-mentioned parameter and receiver has fixing relation, wherein the received optical power of modulation degree that mainly contains transmitter that often changes and receiver (in fact, if not artificial modulation degree is changed, the variation of modulation degree is also very little, influence to output level is very little), the rare variation of other parameter.Under the certain condition of modulation degree and received optical power, the receiver output level is fixed, and output level also can change by certain relation when modulation degree or received optical power change.
Figure 2 shows that optical receiver of the present invention.Comparing with existing receiver as shown in Figure 1, cancelled radio frequency testing circuit 4, is not directly to detect the output level size, but controls the stable of output level by the variation that detects luminous power and information transfer system.Optical receiver comprises Optical Receivers 1, fixed gain rf processing circuitry 2, variable gain treatment circuit 3, direct current optical detecting unit 6, control signal generation circuit 5, webmaster signal processing unit 7 and coupler 8.
After Optical Receivers 1 opto-electronic conversion radiofrequency signal is sent into fixed gain rf processing circuitry 2, fixed gain rf processing circuitry 2 comprises that amplification module, fixed attenuator of fixed gain etc. is to the changeless device of effect of signals, this part realizes determining in actual the use output level not to be had automatic control action when the single board design as required.Signal after fixed gain rf processing circuitry 2 is handled is sent into variable gain treatment circuit 3.
Variable gain treatment circuit 3 is generally the device of gain-variables such as the amplifier, electrically controlled attenuator of (automatic gain control) function that has AGC, and they come the variation of ride gain by a control signal.
Control signal generation circuit 5 produces the control signal that variable gain treatment circuit 3 needs, and control variable gain treatment circuit 3 is realized the stable of output level 9.The control signal of control signal generation circuit 5 output can be by following controlling factors according to different situations: received optical power, user's direct requirement, transmitter percentage modulation webmaster signal also can be one or several combinations in the above-mentioned Several Factors.Wherein the received optical power signal is from direct current optical detecting unit 6, and user's direct requirement, percentage modulation webmaster signal are then from webmaster signal processing unit 7.
Direct current optical detecting unit 6 detect Optical Receivers 1 the direct current luminous power size and deliver to webmaster signal processing unit 7.Luminous power detects except keeping original function among the present invention, and webmaster signal processing unit 7 information is in view of the above judged and produced control signal and sends into control signal generation circuit 5.If keep stable (modulation degree is fixed) of output level in the time of only need considering optical power change, 5 luminous powers of sending into according to direct current optical detecting unit 6 of control signal generation circuit directly produce control signal, and do not need the participation of webmaster signal processing unit 7.
The radiofrequency signal that coupler 8 is coupled out is delivered to the demodulator in the webmaster signal processing circuit 7, and the percentage modulation user command that front end is sent here, the information such as operating state of transmitter are told receiver.
Signal that webmaster signal processing unit 7 processing transmitters transmit and the signal of managing receiver self, the percentage modulation received optical power of transmitter and user's requirement are handled the generation control signal, send into control signal generation circuit 5, produce the control signal that meets user's needs.In fact, not strict or only require stabilizing output level and do not require the identical occasion of whole receiver output levels (modulation degree that does not at this moment need to consider different transmitters is slightly different at index request, and modulation degree is approximate immobilizes), be not need the webmaster signal.
Control signal generation circuit 5 is also delivered to webmaster signal processing unit 7 with the control signal that produces simultaneously, so that whether the control signal of the operating state of supervision control signal generation circuit 5 and generation is normal.
In sum, luminous power, modulation degree or three kinds of signals of user command are all sent into webmaster signal processing unit 7 and are carried out integrated treatment, in case any one changes in user command, luminous power or the modulation degree, output level such as luminous power reduction, modulation degree reduction or customer requirements raises, the control signal that webmaster signal processing unit 7 all can make control signal generation circuit 5 produce diminishes and then attenuation is diminished, and finally realizes stabilization of level or reaches some determined values.
Introduce the present invention below and solving forward receiver and the oppositely concrete application of receiver stabilizing output level control.
Fig. 3 is a kind of typical bi-directional light transmissions pass network configuration.Tx-F, Rx-F, Tx-B, Rx-B represent forward transmitter, forward receiver, back emitted machine and reverse receiver respectively among Fig. 3, and wherein Tx-F and Rx-B are positioned at network front end, and Tx-B and Rx-F are positioned at user side (being generally optical node).Tx-F and Rx-F form the forward transmitted passage; Tx-B and Rx-B constitute reverse channel transmission.For yaw guy, next forward transmitter Tx-F of normal conditions is transferred to a plurality of optical receiver Rx-F by optical branching device.Because the influence of various factors, the forward receiver Rx-F received optical power that is positioned at the optical node place will change and then cause the change of output signal level, and the variation of output signal level will cause the variation of index under many circumstances; The occasion that the transmitter that has automatic modulation degree controlled function in addition changes at channel number, the variation of indivedual channel levels and noise increase all can cause the variation of receiver output signal level.In reverse return system, generally the power output of back emitted machine Tx-B is identical value, because the difference of passback distance will cause that the received optical power at reverse receiver Rx-B place in very large range changes; The modulation degree difference of different in addition back emitted machines, even the signal modulation degree of same transmit machine different frequency range is also different, and (this situation is very general in the back emitted machine, such as transmitting image and data-signal simultaneously, the modulation degree of picture intelligence may be than the modulation degree of digital signal high 10dB even higher; Cause receiver output level different frequency range to differ greatly.This situation restriction can not be adopted existing level detection); The output level of the reverse receiver of result also varies, and is unfavorable for Signal Processing.Adopt the present invention to address the above problem well.
To consider the following fact during practical application of the present invention:
1) in the analog-modulated optical transmission system, generally modulation degree is known;
2) signal gain of Optical Receivers is fixed, information that can be by producer or measure;
3) remainder except variable part of the signal gain in the receiver circuit is fixing and known.
Because above-mentioned three facts, the stabilizing output level that the demand that only needs to consider received optical power, transmitter modulation degree and user just can receiver control arrives any value, and this value is in the scope that receiver provides certainly.Because receiver self output level and received optical power, two factors of modulation degree have relation, can control stabilizing output level in some amplitudes by received optical power and modulation degree.
If the modulation degree of transmitter is fixing and known, so Gu Ding luminous power will produce fixing signal level output.Only need to detect luminous power and just can judge the variation of output level and the output signal of receiver be changed in the opposite direction, just can realize the stable of receiver output level by producing control signal.
In fact run into similar problem through regular meeting, the modulation degree of same transmitter is that fix or variable; The modulation degree of different transmitters may be different; Modulation degree has very little difference, also may be very big difference.All can provide good solution for above-mentioned situation the present invention.
(1) each transmitter modulation degree is that fix and modulation degree different transmitters has very other situation of sub-district.
This situation is the simplest, as long as the control signal generation circuit 5 (shown in Figure 2) of receiver is made fixing, it is stable that the output level of each receiver can keep.The fluctuation of different receivers output signal level is limited by a shade of difference of the modulation degree of different transmitters, and it is very little to calculate this difference.Only cause by the difference of the receiver module signal gain in the receiver.Each piece receive in veneer as the isoparametric nuance of signal gain, can recompense by the fine setting of control signal generation circuit.
(2) each transmitter modulation degree be fix but the situation that the modulation degree of different transmitters alters a great deal.
In this case for the output level that guarantees receiver in some scopes, the modulation degree according to each transmitter when networking realizes adjusting the output level basically identical that makes receiver to the receiver output level of correspondence.Control method is with the little situation of modulation degree difference of above-mentioned transmitter afterwards.
(3) the variable situation of the modulation degree of each transmitter.
In this case, because the variation of modulation degree, even the input optical power of receiver remains unchanged, the output signal level of receiver also can change owing to the variation of modulation degree.In order to guarantee under the situation of input optical power and modulation degree variation, to keep the receiver stabilizing output level, need each transmitter that the relevant informations such as modulation degree of oneself are transferred in the receiver webmaster plate (being the webmaster signal processing unit 7 among Fig. 2) by network management system, produce control corresponding voltage by control of webmaster plate and comprehensive luminous power information, the gain of control main path signal so just can guarantee that whole receiver level output is stable and equal.
Oppositely the level control problem of passback receiver is except the modulation degree problem, because each point is different to the distance of front end, thereby the receiver input optical power changes in very wide scope.Adopt the level control method in the variable system of modulation degree in the forward transmitted to address the above problem well.
The stable method that the present invention utilizes the luminous power of detection receiver to remove the receiver control output level has several outstanding features.One, the generation of control signal only come from the detection of luminous power or are the mixed information of the detection of luminous power and modulation degree, do not need complicated high-frequency signal treatment circuit, and circuit is simple and reliable.Its two for control the high stabilizing output level degree of precision good.Its three, the present invention can finish with the inaccessiable effect of first three methods.Such as adopting the level detection can not guarantee that at all output signal level is stable in the variable occasion of modulation degree; Only need know that by the present invention the modulation degree of corresponding transmitter just can realize the stable and consistent of a plurality of receiver output levels.
The present invention makes full use of the information resources of existing transmitter, can realize high-precision output level control under the situation that does not increase additional firmware at an easy rate.And can expand on this basis that its purposes solves that three kinds of traditional methods can not solve or problem that can not fine solution.Along with the development of optical transmission application technology, can be suitable in more conditions.
Claims (5)
1, a kind of control method of stabilizing output level of light receiver may further comprise the steps:
1) at first detects the size of the received optical power of optical receiver;
2) judge the variation of output level of light receiver according to the size of received optical power;
3) produce control signal according to above-mentioned situation of change the output level of receiver is changed in the opposite direction, to obtain stable output; Return step 1);
It is characterized in that, also detect the information transfer system of transmitter in the described step 1), described step 2) in
Also judge the variation of receiver output level according to the variation of modulation degree.
2, the control method of stabilizing output level of light receiver as claimed in claim 1, it is characterized in that: also detect user's command information in the described step 1), also produce the output level that control signal makes receiver in the described step 3) and reach some determined values according to user command.
3, a kind of optical receiver of realizing stabilizing output level control method as claimed in claim 1 is characterized in that comprising:
Optical Receivers (1) is used for opto-electronic conversion;
Fixed gain rf processing circuitry (2) is used for the amplification of described Optical Receivers (1) electrical signal converted, decay etc.;
Variable gain treatment circuit (3), the signal amplification that is used for described fixed gain rf processing circuitry (2) is sent into, decay etc. come the variation of ride gain by a control signal;
Control signal generation circuit (5) is used to produce the control signal of described variable gain treatment circuit (3) needs;
Direct current optical detecting unit (6) is used to detect the luminous power of described Optical Receivers (1), and sends into described control signal generation circuit (5).
4, optical receiver as claimed in claim 3 is characterized in that: also comprise coupler (8) and webmaster signal processing unit (7),
Described coupler (8) is used for being coupled out information transfer system or user command information is given webmaster signal processing unit (7) from the output signal of variable gain treatment circuit (3);
Described direct current optical detecting unit (6) is also sent into optical power signals webmaster signal processing unit (7);
Described webmaster signal processing unit (7) is used for integrated treatment received optical power, the requirement of percentage modulation user command, sends into described control signal generation circuit (5) to produce control signal.
5, optical receiver as claimed in claim 4, it is characterized in that: described control signal generation circuit (5) is also delivered to webmaster signal processing unit (7) with the control signal that produces simultaneously, so that whether the control signal of the operating state of supervision control signal generation circuit (5) and generation is normal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB991172787A CN1159868C (en) | 1999-12-07 | 1999-12-07 | Control method and device for stabilizing output level of light receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB991172787A CN1159868C (en) | 1999-12-07 | 1999-12-07 | Control method and device for stabilizing output level of light receiver |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1290076A CN1290076A (en) | 2001-04-04 |
| CN1159868C true CN1159868C (en) | 2004-07-28 |
Family
ID=5279914
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB991172787A Expired - Fee Related CN1159868C (en) | 1999-12-07 | 1999-12-07 | Control method and device for stabilizing output level of light receiver |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1159868C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4113824B2 (en) * | 2003-09-24 | 2008-07-09 | シリンクス株式会社 | Receiver circuit for optical space communication |
| CN108551365A (en) * | 2018-03-27 | 2018-09-18 | 西安理工大学 | Wireless ultraviolet light scattering signal adaptive receiving system and method for reseptance |
-
1999
- 1999-12-07 CN CNB991172787A patent/CN1159868C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1290076A (en) | 2001-04-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1298115C (en) | Optical receiving device for realizing luminous power adaptation of different inputs | |
| US20040037569A1 (en) | Method and device for evaluating and improving the quality of transmission of a telecommunications signal through an optical fiber | |
| CN1268078C (en) | Method of power control in optical communication system | |
| CN1202631C (en) | Bidirectional trunk amplifier and modem for cable hybrid fiber and coax network | |
| US8045864B2 (en) | Method and apparatus for processing signals of photo-detector in visible light communication system | |
| CN1134112C (en) | Mobile station having emitting power control system | |
| CN1138339C (en) | Wide range variable output amplifier apparatus with high efficiency | |
| CN1191460A (en) | Wireless base station equipment | |
| US20100158515A1 (en) | Transmission system and test apparatus | |
| US20240305377A1 (en) | Optical module | |
| CN1085478C (en) | Output control unit of mobile communication system and its controlling method | |
| CN1159868C (en) | Control method and device for stabilizing output level of light receiver | |
| US6865015B2 (en) | Method and transmission system for optimization of the transmission characteristics of an optical wavelength division multiplex system | |
| CN1913387A (en) | Method for controlling receive signal levels at a network node in tdma point to multi-point radio communications systems | |
| CN1744473A (en) | Carrier optical receiver front feed automatic gain control method and optical receiver using same | |
| CN101030823A (en) | Optical network unit and its controlling method | |
| CN1666445B (en) | Optical receiver circuit | |
| JP4620509B2 (en) | Optical receiver | |
| CN210491075U (en) | Optical AGC type electric dimming receiver | |
| CN1147075C (en) | Single-fiber two-way integral optical module for burst transmission | |
| CN1135835C (en) | Four-phase shift keying modulated signal receiving assembly | |
| CN201571025U (en) | Optical AGC control circuit used for optical receiver | |
| CN208063212U (en) | A kind of radio frequency fiber optic receiving terminal of communication system based on voltage-controlled optical attenuator | |
| CN1132043C (en) | Operation of optical modulators | |
| CN1914920A (en) | Optical signal receiver and optical signal transmitter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20040728 Termination date: 20131207 |