Cable television optical node capable of automatically switching wavelength

Abstract

The utility model discloses a cable television optical node capable of automatically switching wavelength, which is characterized in that a mixed end of a bidirectional filter circuit is connected with a radio-frequency signal of a cable television bidirectional hybrid optical fiber coaxial network, and a low-frequency end of the bidirectional filter circuit is connected with an input end of a first uplink amplification circuit; the output end of the first uplink amplification circuit is connected with the input end of the uplink attenuation circuit, the output end of the uplink attenuation circuit is connected with the input end of the second uplink amplification circuit, and the output end of the second uplink amplification circuit is connected with the light emitting and receiving circuit. The optical transmitting and receiving circuit is connected with an optical signal of the cable television bidirectional hybrid optical fiber coaxial network; the output end of the light emitting and receiving circuit is connected with the input end of the first downlink amplification circuit, the output end of the first downlink amplification circuit is connected with the input end of the downlink attenuation circuit, and the output end of the downlink attenuation circuit is connected with the input end of the second downlink amplification circuit. And the output end of the second downlink amplification circuit is connected with the high-frequency end of the bidirectional filter circuit.

Description

Technical Field

[0001] The utility model relates to the technical field of cable television, in particular to a cable television optical node with automatic wavelength switching. Background Art

[0002] Optical nodes are important transmission equipment in the bidirectional HFC network of cable TV and are widely used in cable TV systems. As the number of optical nodes increases, the return channel will have optical beat frequency interference noise when the same optical wavelength is accessed. Currently, the eight optical nodes in the same work group use optical nodes with different return optical wavelengths to solve the return noise problem. However, in the actual construction process, it is necessary to understand the optical wavelengths of the other seven optical nodes in the same work group, which sometimes causes a lot of work for cable TV network installation and maintenance personnel.

[0003] Aiming at the problems existing in the prior art, a cable television optical node with automatic wavelength switching is provided. Utility Model Content

[0004] The utility model aims to provide a cable television optical node with automatic wavelength switching in view of the defects of the prior art.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A cable television optical node with automatic wavelength switching, comprising a bidirectional filtering circuit, a first uplink amplifying circuit, an uplink attenuation circuit, a second uplink amplifying circuit, an optical transmitting and receiving circuit, a first downlink amplifying circuit, a downlink attenuation circuit, a second downlink amplifying circuit, a microprocessor circuit, and a wavelength control circuit;

[0007] The hybrid end of the bidirectional filtering circuit is connected to the radio frequency signal of the cable television bidirectional hybrid fiber-coaxial network, the low frequency end of the bidirectional filtering circuit is connected to the input end of the first uplink amplifier circuit, the output end of the first uplink amplifier circuit is connected to the input end of the uplink attenuation circuit, the output end of the uplink attenuation circuit is connected to the input end of the second uplink amplifier circuit, the output end of the second uplink amplifier circuit is connected to the optical transmitting and receiving circuit, and the optical transmitting and receiving circuit is connected to the optical signal of the cable television bidirectional hybrid fiber-coaxial network;

[0008] The output end of the optical transmitting and receiving circuit is connected to the input end of the first downstream amplifier circuit, the output end of the first downstream amplifier circuit is connected to the input end of the downstream attenuation circuit, the output end of the downstream attenuation circuit is connected to the input end of the second downstream amplifier circuit, and the output end of the second downstream amplifier circuit is connected to the high frequency end of the bidirectional filtering circuit;

[0009] The microprocessor circuit is connected with the downlink attenuation circuit and the wavelength control circuit respectively, and the wavelength control circuit is connected with the optical transmitting and receiving circuit.

[0010] Furthermore, the model of the bidirectional filtering circuit is ZBB 5-85 / 102-1218MH.

[0011] Furthermore, the first uplink amplifier circuit adopts an AE312 amplifier chip.

[0012] Furthermore, the second uplink amplifier circuit adopts a ZD1020 power amplifier chip.

[0013] Furthermore, the optical transmitting and receiving circuit adopts a model of

[0014] YY-PSA-D6120H-55F-2GR(TEC).

[0015] Furthermore, the first downstream amplifier circuit adopts a ZD1008 low-noise amplifier chip.

[0016] Furthermore, the second downstream amplifier circuit adopts a ZD1027 power amplifier chip.

[0017] Furthermore, the model of the downlink attenuation circuit is ARW621A.

[0018] Furthermore, the microprocessor circuit adopts a single chip microcomputer model STC12C5620AD.

[0019] Furthermore, the wavelength control circuit adopts the model ADN8831.

[0020] Compared with the prior art, the cable TV optical node with automatic wavelength switching of the utility model can not only solve the problem of optical beat frequency interference noise in the optical node return channel, but also reduce the workload of cable TV network installation and maintenance personnel and improve labor efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a structural diagram of a cable television optical node with automatic wavelength switching provided by an embodiment. DETAILED DESCRIPTION

[0022] The following describes the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0023] The utility model aims to provide a cable television optical node with automatic wavelength switching in view of the defects of the prior art.

[0024] Example

[0025] This embodiment provides a cable television optical node with automatic wavelength switching, such as Figure 1 As shown, it is installed at the user end of a cable TV bidirectional hybrid fiber-coaxial network (i.e., a bidirectional HFC network), and includes a bidirectional filtering circuit 1, a first uplink amplifier circuit 2, an uplink attenuation circuit 3, a second uplink amplifier circuit 4, an optical transmitting and receiving circuit 5, a first downlink amplifier circuit 6, a downlink attenuation circuit 7, a second downlink amplifier circuit 8, a microprocessor circuit 9, and a wavelength control circuit 10.

[0026] The hybrid end of the bidirectional filtering circuit 1 is the RF signal port of the cable TV optical node. The hybrid end of the bidirectional filtering circuit 1 is connected to the RF signal of the cable TV bidirectional HFC network, and then receives the uplink RF signal of the cable TV bidirectional HFC network; the low-frequency end of the bidirectional filtering circuit 1 is connected to the input end of the first uplink amplifier circuit 2, the output end of the first uplink amplifier circuit 2 is connected to the input end of the uplink attenuation circuit 3, the output end of the uplink attenuation circuit 3 is connected to the input end of the second uplink amplifier circuit 4, the output end of the second uplink amplifier circuit 4 is connected to the optical transmitting and receiving circuit 5, and the uplink optical transmission signal of the optical transmitting and receiving circuit 5 is connected to the optical signal port of the cable TV bidirectional HFC network.

[0027] The downlink optical signal is connected to the optical transmitting and receiving circuit 5 through the optical signal port, the output end of the optical transmitting and receiving circuit 5 is connected to the input end of the first downlink amplifier circuit 6, the output end of the first downlink amplifier circuit 6 is connected to the input end of the downlink attenuation circuit 7, the output end of the downlink attenuation circuit 7 is connected to the input end of the second downlink amplifier circuit 8, and the output end of the second downlink amplifier circuit 8 is connected to the high frequency end of the bidirectional filtering circuit 1; the mixing end of the bidirectional filtering circuit 1 is the RF signal port of the cable TV optical node, which receives the downlink RF signal of the cable TV bidirectional HFC network.

[0028] The microprocessor circuit 9 is connected to the downlink attenuation circuit 7 and the wavelength control circuit 10 respectively, and the wavelength control circuit 10 is connected to the optical transmitting and receiving circuit 5 .

[0029] The bidirectional filtering circuit 1 adopts the product of Zheguang Technology, model ZBB 5-85 / 102-1218MH. The operating frequency range of the uplink RF signal is 5-85MHz, and the operating frequency range of the downlink RF signal is 102-1218MHz. The bidirectional filtering circuit has good in-band flatness, high reflection loss and mutual isolation, and low signal insertion loss.

[0030] The first uplink amplifier circuit 2 uses the AE312 amplifier chip of RFHIC Company, with an operating frequency range of 5-2700MHz and a gain of 20dB. The uplink amplifier circuit 1 composed of this chip has the characteristics of low noise coefficient and high gain.

[0031] The uplink attenuation circuit 3 is a RF signal π-type attenuation circuit composed of resistors. By adjusting the attenuation of the π-type attenuation circuit, the RF signal level input to the laser in the optical transmitting and receiving circuit can be adjusted so that the laser works in the best state.

[0032] The second uplink amplifier circuit 4 adopts the ZD1020 power amplifier chip of Beijing Zhongdian Hongye, with an operating frequency range of 5-3000MHz and a gain of 21dB. The uplink amplifier circuit 2 composed of this chip has the characteristics of low noise and high linearity.

[0033] The optical transmitting and receiving circuit 5 adopts the optical component of Sichuan Yuyi Optoelectronic Technology Co., Ltd., model number is YY-PSA-D6120H-55F-2GR (TEC), the optical component includes a DFB-LD laser with an electronic refrigerator, the wavelength is tunable within 1607-1613nm, and the output power is 2mW; including an InGaAs PIN-PD photoelectric receiving tube with a wavelength of 1550nm; including a wavelength division multiplexer with a wavelength of 1610nm and 1550nm. The uplink radio frequency signal amplified by the second uplink amplifier circuit 4 is modulated into a cable TV uplink optical signal through the DFB-LD laser and output through the optical signal port; the cable TV downlink optical signal input through the optical signal port is converted into a downlink radio frequency signal through the InGaAs PIN-PD photoelectric receiving tube of the optical transmitting and receiving circuit 5.

[0034] The first downstream amplifier circuit 6 adopts the ZD1008 low-noise amplifier chip produced by Beijing Zhongdian Hongye, with an operating frequency range of 40-1200MHz and a gain of 20dB. The downstream amplifier circuit 1 composed of this chip has the characteristic of low noise.

[0035] The second downstream amplifier circuit 8 adopts the ZD1027 power amplifier chip of Beijing Zhongdian Hongye, with an operating frequency range of 40-1200MHz and a gain of 26dB. The downstream amplifier circuit 2 composed of this chip has the characteristics of low noise, high gain and high linearity.

[0036] The downlink attenuation circuit 7 adopts the digital programmable RF attenuation chip of Shanghai Anqiwei Company, model ARW621A, with an operating frequency range of 1-6000MHz and a step attenuation of 0.5dB. The attenuation can be controlled through the serial port of the microprocessor circuit 9 so that the RF output signal of the optical node reaches the nominal level value.

[0037] The microprocessor circuit 9 adopts the STC12C5620AD single chip microcomputer of Hongjing Technology Company.

[0038] The wavelength control circuit 10 uses ADN8831 of ADI Conductor Company as the control chip of the laser electronic refrigerator (TEC). Since the wavelength of the laser output optical signal and the laser temperature are in a relationship of 0.1nm / ℃, the ADN8831 chip is a TEC driver module with high integration, high output efficiency and high performance, which can control the set temperature error to about ±0.01℃. During operation, by setting different voltage values ​​at the input end of ADN8831, currents corresponding to different current directions and different current values ​​flow through the TEC in the laser, so that the TEC is heated or cooled, and corresponds to a set target temperature, so that the laser can output an optical signal of a corresponding wavelength. By controlling the time intervals of different current directions and different current values ​​through the microprocessor circuit 9, the automatic switching of different wavelengths of the output optical signal can be realized. The wavelength of the output optical signal when the optical node is turned on is randomly set. After the optical node is turned on, the wavelength of the output optical signal of the optical node is automatically switched between 32 different wavelengths every hour.

[0039] The cable TV optical node with automatic wavelength switching can make the wavelength of the optical signal transmitted in the return channel of the cable TV network one of 32 different wavelengths, and the output wavelength is switched regularly at intervals of one hour. Due to the different startup times, the eight optical nodes in the same working group in the cable TV network are likely to output return optical signals of different wavelengths, which not only solves the problem of optical beat frequency interference noise in the return channel, but also facilitates the construction of cable TV network installation and maintenance personnel and improves labor efficiency.

[0040] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A cable television optical node with automatic wavelength switching, characterized in that: It includes a bidirectional filtering circuit, a first uplink amplifying circuit, an uplink attenuation circuit, a second uplink amplifying circuit, an optical transmitting and receiving circuit, a first downlink amplifying circuit, a downlink attenuation circuit, a second downlink amplifying circuit, a microprocessor circuit, and a wavelength control circuit; The hybrid end of the bidirectional filtering circuit is connected to the radio frequency signal of the cable television bidirectional hybrid fiber-coaxial network, the low frequency end of the bidirectional filtering circuit is connected to the input end of the first uplink amplifier circuit, the output end of the first uplink amplifier circuit is connected to the input end of the uplink attenuation circuit, the output end of the uplink attenuation circuit is connected to the input end of the second uplink amplifier circuit, the output end of the second uplink amplifier circuit is connected to the optical transmitting and receiving circuit, and the optical transmitting and receiving circuit is connected to the optical signal of the cable television bidirectional hybrid fiber-coaxial network; The output end of the optical transmitting and receiving circuit is connected to the input end of the first downstream amplifier circuit, the output end of the first downstream amplifier circuit is connected to the input end of the downstream attenuation circuit, the output end of the downstream attenuation circuit is connected to the input end of the second downstream amplifier circuit, and the output end of the second downstream amplifier circuit is connected to the high frequency end of the bidirectional filtering circuit; The microprocessor circuit is connected with the downlink attenuation circuit and the wavelength control circuit respectively, and the wavelength control circuit is connected with the optical transmitting and receiving circuit.

2. A cable television optical node with automatic wavelength switching according to claim 1, characterized in that: The model used in the bidirectional filtering circuit is ZBB 5-85 / 102-1218MH.

3. A cable television optical node with automatic wavelength switching according to claim 2, characterized in that: The first uplink amplifier circuit adopts the AE312 amplifier chip.

4. A CATV optical node with automatic wavelength switching according to claim 3, characterized in that: The second uplink amplifier circuit adopts the ZD1020 power amplifier chip.

5. A CATV optical node with automatic wavelength switching according to claim 4, characterized in that: The model of the optical transmitting and receiving circuit is YY-PSA-D6120H-55F-2GR (TEC).

6. A CATV optical node with automatic wavelength switching according to claim 5, characterized in that: The first downstream amplifier circuit adopts the ZD1008 low-noise amplifier chip.

7. A CATV optical node with automatic wavelength switching according to claim 6, characterized in that: The second downstream amplifier circuit adopts the ZD1027 power amplifier chip.

8. A CATV optical node with automatic wavelength switching according to claim 7, characterized in that: The model used by the downlink attenuation circuit is ARW621A.

9. A CATV optical node with automatic wavelength switching according to claim 8, characterized in that: The microprocessor circuit adopts the STC12C5620AD single chip microcomputer.

10. A cable television optical node with automatic wavelength switching according to claim 9, characterized in that: The wavelength control circuit adopts the model ADN8831.

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