CN111970053A - Demodulation device for top modulation signal and optical module - Google Patents
Demodulation device for top modulation signal and optical module Download PDFInfo
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- CN111970053A CN111970053A CN202010803394.XA CN202010803394A CN111970053A CN 111970053 A CN111970053 A CN 111970053A CN 202010803394 A CN202010803394 A CN 202010803394A CN 111970053 A CN111970053 A CN 111970053A
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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
- H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
- H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
- H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
- H04B10/0795—Performance monitoring; Measurement of transmission parameters
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
Abstract
The invention relates to a demodulation device of a pilot tone signal and an optical module, comprising: a sampling circuit and an amplifying circuit; the sampling circuit is used for carrying out alternating current coupling on the input RSSI voltage signal to remove a direct current component in the RSSI voltage signal and outputting an alternating current signal; the amplifying circuit is used for amplifying the input alternating current signal and then outputting the amplified alternating current signal to the comparator for judgment and recovery to obtain a modulation signal. The invention has the beneficial effects that: through adopting the sampling circuit to carry out ac coupling to the RSSI voltage signal of sampling resistance output, reject the direct current composition on the RSSI signal, the problem that the signal is easy to saturate when having solved conventional scheme and going up the highlight to the amplifier circuit has been added to the rear end and has realized several times (or tens of times) the enlargies to the alternating current signal of input, the problem that signal amplitude is little under the solution weak light (and the signal also can not distort under the highlight), can promote detection circuitry's dynamic range 10dB and above, signal detection's dynamic range has fully been enlarged.
Description
Technical Field
The invention belongs to the technical field of optical communication modules, and particularly relates to a top-modulation signal demodulation device and an optical module.
Background
With the rapid development of 5G wireless communication technology, wavelength division multiplexing optical modules are increasingly applied to 5G devices. For example, a 12-wave tunable optical module based on Dense Wavelength Division Multiplexing (DWDM), or a 20-wave tunable optical module; a 12-wave optical module based on Medium Wavelength Division Multiplexing (MWDM) and a 12-wave optical module based on fine wavelength division multiplexing (Lan-WDM). In order to facilitate the management of the wavelength division multiplexing optical module with a plurality of channels, the function of the wavelength division multiplexing optical module with a 'network management' is gradually changed into 'standard allocation': the communication channel established by the optical module is multiplexed, and the near-end equipment can flexibly control the far-end equipment without adding an additional communication channel, so that the operation cost is saved.
The 'network management' function of the wavelength division multiplexing module is usually realized by adopting a 'tuning top' technology, namely, a low-frequency driving circuit is added at the transmitting end of an optical module, and a low-frequency modulation signal is loaded on a laser through the driving circuit and is used for modulating the amplitude of an output optical signal in a small amplitude (generally, the modulation depth of the low frequency is less than 10%); the receiving end of the optical module detects the intensity change of the photoelectric conversion signal (RSSI), and makes a decision through the comparison circuit to recover the modulation signal, so that a signal processing unit (such as an MCU) at the later stage can analyze a corresponding 'network management' instruction, and the circuit principle is as shown in fig. 1:
the RSSI is a current signal of photoelectric conversion, and generally comes from the output of a transimpedance amplifier (TIA) of a receiving device, or the output of some mirror image photoelectric conversion current circuits (including the mirror image current output of an integrated chip, such as the RSSI output of an APD type boost control chip, etc.), and the sampling resistor R1 is used for converting the RSSI current signal into an RSSI voltage signal for the comparator U2 to use; the reference level circuit U1 provides a dc level decision threshold for the comparator U2, and the output signal after the decision of the comparator U2 is the recovered modulation signal.
Because the RSSI current signal dynamic range of the photoelectric conversion is large (for example, the current may reach mA level under strong light, and reach uA level under weak light), the sampling resistor R1 is generally kilo-ohm (Kohm) level, and the voltage signal converted by R1 has a difference of several tens times (or hundreds times) between strong light and weak light, which may cause the signal under strong light to easily reach the upper level limit (saturation) of the circuit, and cause U2 to be unable to correctly distinguish; the signal amplitude under weak light is too small, and is easily interfered by power supply noise or other noises, so that signal distortion is caused, and further the comparator U2 misjudges, so that the dynamic range of signal detection is insufficient.
Disclosure of Invention
The invention provides a top-modulation signal demodulation device and an optical module, which have the characteristics of fully expanding the dynamic range of signal detection and the like, and aims to solve the problems that signals under strong light easily reach the upper level limit (saturation) of a circuit and the amplitude of signals under weak light is too small to be easily interfered so that the dynamic range of signal detection is insufficient in the prior art.
A demodulation apparatus for a pilot tone signal according to an embodiment of the present invention includes: a sampling circuit and an amplifying circuit;
the sampling circuit is used for carrying out alternating current coupling on an input RSSI voltage signal to remove a direct current component in the RSSI voltage signal and outputting an alternating current signal;
the amplifying circuit is used for amplifying the input alternating current signal and then outputting the amplified alternating current signal to the comparator for judgment and recovery to obtain a modulation signal.
Further, the demodulation apparatus for the pilot tone signal further includes: and the decision threshold circuit is arranged between the amplifying circuit and the comparator and is used for filtering the amplifying signal output by the amplifying circuit and outputting a direct current mean level as a direct current level decision threshold of the comparator.
Further, the sampling circuit includes: and the coupling capacitor is connected between the sampling resistor and the amplifying circuit and is used for carrying out alternating current coupling on the RSSI voltage signal.
Further, the amplifying circuit is a proportional amplifying circuit, an input end of which is connected with the coupling capacitor, and an output end of which is respectively connected with the decision threshold circuit and the comparator.
Further, the proportional amplification circuit comprises an amplifier, a first resistor and a second resistor;
the first input end of the amplifier is connected with the coupling capacitor, and the output end of the amplifier is respectively connected with the decision threshold circuit and the comparator;
one end of the first resistor is grounded, and the other end of the first resistor is connected with the second input end of the amplifier;
one end of the second resistor is connected with the second input end of the amplifier, and the other end of the second resistor is connected with the output end of the amplifier.
Furthermore, the sampling circuit further comprises an anti-interference branch, one end of the anti-interference branch is connected between the sampling resistor and the grounding point, and the other end of the anti-interference branch is connected with a second input end of the amplifier and used for filtering interference signals in the RSSI voltage signals.
Further, the anti-jamming branch comprises: a third resistor and a first filter, the third resistor being connected between the sampling resistor and the ground point;
one end of the first filter is connected with a connection point of the third resistor and the sampling resistor, and the other end of the first filter is connected with the second input end of the amplifier.
Further, the decision threshold circuit is a second filter connected between the amplifying circuit and the comparator.
Further, the first filter and the second filter are both active filters.
According to the embodiment of the invention, the optical module comprises the demodulation device for the pilot tone signal.
The invention has the beneficial effects that: through adopting the sampling circuit to carry out ac coupling to the RSSI voltage signal of sampling resistance output, reject the direct current composition on the RSSI signal, the problem that the signal is easy to saturate when having solved conventional scheme and going up the highlight to the amplifier circuit has been added to the rear end and has realized the enlarging of several times (or tens of times) to the alternating current signal of input, the problem that signal amplitude is little under the weak light is solved (and the signal also can not distort under the highlight), can promote detection circuitry's dynamic range 10dB and above, signal detection's dynamic range has fully been enlarged.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic diagram of a prior art tune-to-tune signal detection circuit provided in accordance with an exemplary embodiment;
fig. 2 is a schematic diagram of a set-top signal demodulation apparatus provided in accordance with an example embodiment;
fig. 3 is another schematic diagram of a set-top signal demodulation apparatus provided in accordance with an exemplary embodiment;
fig. 4 is a circuit diagram of a demodulation apparatus for a pilot tone signal according to an exemplary embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.
Referring to fig. 2, an embodiment of the present invention provides a demodulation apparatus for a pilot tone signal, including: a sampling circuit and an amplifying circuit;
the sampling circuit is used for carrying out alternating current coupling on an input RSSI voltage signal to remove a direct current component in the RSSI voltage signal and outputting an alternating current signal;
the amplifying circuit is used for amplifying the input alternating current signal and then outputting the amplified alternating current signal to the comparator for judgment and recovery to obtain a modulation signal.
Specifically, the RSSI current signal generally comes from the output of a transimpedance amplifier (TIA) of an optical module receiving device, or the output of some mirror image photoelectric conversion current circuits (including the mirror image current output of an integrated chip, such as the RSSI output of an APD type boost control chip); the current signal is converted into an RSSI voltage signal through a sampling resistor R1, the sampling circuit is used as the sampling input of the demodulation device circuit, the voltage signals at two ends of the R1 can be collected in a differential mode, common mode signals on the RSSI voltage signal can be eliminated, alternating current coupling is carried out, and then direct current components on the RSSI signal can be eliminated, so that the problem that the signal is easy to saturate in strong light in the conventional scheme is solved; the amplifying circuit can amplify the processed alternating current signals, can amplify the input alternating current signals by multiple times (or tens of times) according to the requirements of product design, solves the problem of small signal amplitude under weak light (and the signals cannot be distorted under strong light), can improve the dynamic range of the detection circuit by 10dB or more, thus not only avoiding the saturated distortion caused by the direct current large signals, but also eliminating the common mode noise in the circuit, improving the detection capability of the small signals and greatly improving the dynamic range of signal detection.
In order to further optimize the technical solution, referring to fig. 3, some embodiments of the present invention further include: and the judgment threshold circuit is arranged between the amplifying circuit and the comparator U2 and is used for filtering the amplified signal output by the amplifying circuit and outputting a direct current mean level as a direct current level judgment threshold of the comparator U2.
The signal amplified by the amplifying circuit is divided into two paths, one path directly enters one input end of the comparator U2, the other path outputs a direct current mean value level signal after being processed by the decision threshold circuit and enters the other input end of the comparator U2 to be used as a decision threshold, and the decision level of the comparator U2 directly comes from the direct current mean value of the input signal, so that the decision threshold can be correspondingly changed along with the change of the input signal, and the problem that the reference level of a conventional 'top-regulating' signal detection circuit is difficult to control is effectively solved.
It should be noted that the comparator U2 may be an independent device, or may be a part of a functional unit of some integrated circuits, for example, a comparator is integrated inside some single chip, and the present invention is not limited herein.
As a possible implementation manner of the above embodiment, referring to fig. 4, the sampling circuit F1 includes: the coupling capacitor C1 and the coupling capacitor C1 are connected between the sampling resistor R1 and the amplifying circuit F2, and are used for ac coupling of the RSSI voltage signal.
The amplifying circuit F2 is formed by connecting the input end of a proportional amplifying circuit with a coupling capacitor C1, and the output end of the proportional amplifying circuit is respectively connected with a decision threshold circuit F3 and a comparator U2.
The proportional amplifying circuit comprises an amplifier U3, a first resistor R3 and a second resistor R4;
a first input end of the amplifier U3 is connected with the coupling capacitor C1, and output ends of the amplifier are respectively connected with the decision threshold circuit and the comparator U2;
one end of the first resistor R3 is grounded, and the other end of the first resistor R3 is connected with the second input end of the amplifier U3;
one end of the second resistor R4 is connected to the second input terminal of the amplifier U3, and the other end of the second resistor R4 is connected to the output terminal of the amplifier U3.
The sampling circuit further comprises an anti-interference branch circuit, one end of the anti-interference branch circuit is connected between the sampling resistor R1 and the grounding point, and the other end of the anti-interference branch circuit is connected with a second input end of the amplifier U3 and used for filtering interference signals in the RSSI voltage signals.
The anti-interference branch road includes: the third resistor R2 and the first Filter1, and the third resistor R2 is connected between the sampling resistor R1 and the grounding point;
one end of the first Filter1 is connected with the connection point of the third resistor R2 and the sampling resistor R1, and the other end of the first Filter1 is connected with the second input end of the amplifier U3. The Filter1 is used for carrying out active filtering on the sampling signal, eliminating noise and improving the anti-interference capability of the circuit, and when the noise in the specifically applied circuit is small, the sampling circuit F1 can be changed into single-ended sampling, namely R2 and the Filter1 can be removed, so that the circuit structure is simpler and the degree of integration is improved. Or certain elements may be added or removed, and the invention is not limited thereto.
The decision threshold circuit is that the second Filter2 is connected between the amplifying circuit and the comparator, namely the output direct current mean level between the amplifier U3 and the comparator U2 is used as the decision threshold, and the decision threshold circuit changes correspondingly along with the change of the input signal, thereby effectively solving the problem that the reference level of the conventional 'tuning top' signal detection circuit is difficult to control.
The first Filter1 and the second Filter2 are both active filters.
It is understood that those skilled in the art can also use other filtering methods to perform the filtering process, and the invention is not limited herein.
In some specific applications, R1 and R2 are selected in the range of 1K-10K, and no specific proportion requirement exists; r3 and R4 are in a range of 1K-100K, and form an amplifying circuit according to design requirements, and have a certain ratio relationship, for example, if the amplification is 20 times, then R4/R3 is 20K/1K or 40K/2K, and those skilled in the art can select the circuit according to requirements, and the invention is not limited herein;
the U3 amplifier may be an integrated operational amplifier such as the 8605 series.
In other embodiments of the present invention, an optical module is further provided, which includes the demodulation apparatus for a pilot tone signal provided in the foregoing embodiments. For specific implementation of the optical module, reference may be made to the specific implementation of the above demodulation apparatus for a pilot tone signal, and details of the present invention are not repeated herein.
According to the demodulation device and the optical module for the pilot tone signal provided by the embodiment of the invention, through the adoption of alternating current coupling, the direct current component in the RSSI signal is removed, and the alternating current signal of the pilot tone signal is taken out, so that the signal amplification of a post-stage amplification circuit is facilitated, and the saturation distortion caused by a large direct current signal is avoided; differential sampling of RSSI voltage signals is adopted, common mode noise in a circuit is eliminated, and the detection capability of small signals is improved; the amplifying circuit is adopted to amplify the top-adjusted alternating current signal, so that the dynamic range of signal detection is greatly improved; the decision threshold circuit with the automatic adjustment function can output the corresponding average direct current quantity according to the input alternating current amplification signal to serve as a decision threshold, so that the accuracy of the decision circuit is improved, and the debugging work of the detection circuit is greatly reduced.
It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.
In addition, functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the embodiments described herein are intended to embrace all such alterations, modifications and variations that fall within the scope of the appended claims. Furthermore, to the extent that the term "includes" is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim. Furthermore, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or".
It should be noted that the terms "first," "second," and the like in the description of the present invention are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Further, in the description of the present invention, the meaning of "a plurality" means at least two unless otherwise specified.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (10)
1. A demodulation apparatus for a pilot tone signal, comprising: a sampling circuit and an amplifying circuit;
the sampling circuit is used for carrying out alternating current coupling on an input RSSI voltage signal to remove a direct current component in the RSSI voltage signal and outputting an alternating current signal;
the amplifying circuit is used for amplifying the input alternating current signal and then outputting the amplified alternating current signal to the comparator for judgment and recovery to obtain a modulation signal.
2. The apparatus for demodulating a modulated signal according to claim 1, further comprising: and the decision threshold circuit is arranged between the amplifying circuit and the comparator and is used for filtering the amplifying signal output by the amplifying circuit and outputting a direct current mean level as a direct current level decision threshold of the comparator.
3. The apparatus according to claim 2, wherein said sampling circuit comprises: and the coupling capacitor is connected between the sampling resistor and the amplifying circuit and is used for carrying out alternating current coupling on the RSSI voltage signal.
4. The apparatus according to claim 3, wherein the input terminal of the amplifying circuit is connected to the coupling capacitor, and the output terminal of the amplifying circuit is connected to the decision threshold circuit and the comparator, respectively.
5. The apparatus according to claim 4, wherein said scaling circuit comprises an amplifier, a first resistor and a second resistor;
the first input end of the amplifier is connected with the coupling capacitor, and the output end of the amplifier is respectively connected with the decision threshold circuit and the comparator;
one end of the first resistor is grounded, and the other end of the first resistor is connected with the second input end of the amplifier;
one end of the second resistor is connected with the second input end of the amplifier, and the other end of the second resistor is connected with the output end of the amplifier.
6. The set-top signal demodulation apparatus of claim 5, wherein the sampling circuit further comprises an anti-jamming branch, one end of the anti-jamming branch is connected between the sampling resistor and the ground point, and the other end of the anti-jamming branch is connected to the second input terminal of the amplifier for filtering the jamming signal in the RSSI voltage signal.
7. The apparatus according to claim 6, wherein said interference rejection branch comprises: a third resistor and a first filter, the third resistor being connected between the sampling resistor and the ground point;
one end of the first filter is connected with a connection point of the third resistor and the sampling resistor, and the other end of the first filter is connected with the second input end of the amplifier.
8. The apparatus as claimed in claim 7, wherein said decision threshold circuit is a second filter connected between said amplifying circuit and said comparator.
9. The apparatus as claimed in claim 8, wherein said first filter and said second filter are both active filters.
10. An optical module comprising the demodulation apparatus for a pilot signal according to any one of claims 1 to 9.
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| CN202010803394.XA CN111970053A (en) | 2020-08-11 | 2020-08-11 | Demodulation device for top modulation signal and optical module |
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| CN202010803394.XA CN111970053A (en) | 2020-08-11 | 2020-08-11 | Demodulation device for top modulation signal and optical module |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112929093A (en) * | 2021-02-25 | 2021-06-08 | 索尔思光电（成都）有限公司 | OAM signal top-adjusting circuit |
| CN112968734A (en) * | 2021-02-24 | 2021-06-15 | 东莞铭普光磁股份有限公司 | Optical module, method for realizing network management function of optical module and optical communication equipment |
| CN113300776A (en) * | 2021-04-30 | 2021-08-24 | 武汉联特科技股份有限公司 | Circuit and method for improving top-adjusting sensitivity |
| CN113438029A (en) * | 2021-05-31 | 2021-09-24 | 深圳市极致兴通科技有限公司 | OAM signal demodulation method, system and storage medium |
| CN113949449A (en) * | 2021-09-24 | 2022-01-18 | 昂纳信息技术（深圳）有限公司 | Photodiode detection circuit, optical module, monitoring system and monitoring method thereof |
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2020
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112968734A (en) * | 2021-02-24 | 2021-06-15 | 东莞铭普光磁股份有限公司 | Optical module, method for realizing network management function of optical module and optical communication equipment |
| CN112968734B (en) * | 2021-02-24 | 2022-05-03 | 东莞铭普光磁股份有限公司 | Optical module, method for realizing network management function of optical module and optical communication equipment |
| CN112929093A (en) * | 2021-02-25 | 2021-06-08 | 索尔思光电（成都）有限公司 | OAM signal top-adjusting circuit |
| CN112929093B (en) * | 2021-02-25 | 2023-03-31 | 索尔思光电（成都）有限公司 | OAM signal top-adjusting circuit |
| CN113300776A (en) * | 2021-04-30 | 2021-08-24 | 武汉联特科技股份有限公司 | Circuit and method for improving top-adjusting sensitivity |
| CN113300776B (en) * | 2021-04-30 | 2022-08-16 | 武汉联特科技股份有限公司 | Circuit and method for improving top-adjusting sensitivity |
| CN113438029A (en) * | 2021-05-31 | 2021-09-24 | 深圳市极致兴通科技有限公司 | OAM signal demodulation method, system and storage medium |
| CN113949449A (en) * | 2021-09-24 | 2022-01-18 | 昂纳信息技术（深圳）有限公司 | Photodiode detection circuit, optical module, monitoring system and monitoring method thereof |
| CN113949449B (en) * | 2021-09-24 | 2023-11-17 | 昂纳科技(深圳)集团股份有限公司 | Photodiode detection circuit, optical module, monitoring system and monitoring method thereof |
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