CN202364229U

CN202364229U - Optical receiving circuit

Info

Publication number: CN202364229U
Application number: CN2011205285339U
Authority: CN
Inventors: 刘勇刚
Original assignee: SHENZHEN SANLAND ELECTRONIC CO Ltd
Current assignee: SHENZHEN WANHE TECHNOLOGY CO., LTD.
Priority date: 2011-12-16
Filing date: 2011-12-16
Publication date: 2012-08-01
Anticipated expiration: 2021-12-16

Abstract

The utility model discloses an optical receiving circuit which comprises a photoelectric conversion unit, a gain adjusting unit and a sample processing unit, wherein the improvement is as follows: the optical receiving unit also comprises a radio frequency signal amplifying unit and a microcomputer processing unit; a signal output end of the photoelectric conversion unit is electrically connected to an input end of the radio frequency signal amplifying unit and an input end of the sample processing unit respectively; an output end of the radio frequency signal amplifying unit is electrically connected to the gain adjusting unit; and an output end of the sample processing unit is electrically connected to an input end of the microcomputer processing unit, and an output end of the microcomputer processing unit is electrically connected to a control end of the gain adjusting unit. The optical receiving circuit has the beneficial effects that the level of attenuated electric signal is stably kept; an adjusting range of the gain adjusting unit is within 0-20dB, and a control range (corresponding to the adjustment range) of the gain adjusting unit is also improved to -8dBm to +2dBm, and therefore, requirements of all users are met, the control precision is high, and an electric signal which is finally output is stable.

Description

Optical receiving circuit

[technical field]

The utility model relates to optical receiving circuit, particularly a kind of optical receiving circuit of automatic gain control.

[background technology]

Along with the fast development of electronic technology and optical fiber communication technology, optical-fibre communications is low because of the loss that it has, transmission frequency bandwidth, capacity is big, volume is little, electromagnetic interference in light weight, anti-, be difficult for advantages such as cross-talk, enjoys the insider to favor, and develops very fast.At present, optical fiber cable has got into the every field of wire communication, comprises fields such as post and telecommunications, broadcast communication, power communication, oil communication and military communication.Generally speaking, in order to reach farther Distance Transmission, often increase the Optical Receivers that can receive the faint light power signal at the terminal of Optical Fiber Transmission; Because optical power signals has loss in various degree in the process of transmission, so in the optical power signals of terminal node certain excursion is arranged, the jitter after amplifying; Therefore, need a control circuit to come the steady of regulating and controlling output voltage, the control range of AGC control circuit of the prior art is little; Be generally-6～0dBm; Because these two kinds of schemes all design on the mainboard, the dynamic range of index is restricted, for greater than-6～0dBm scope; Its control action is very not obvious, can not satisfy all users' the scope of application.

[utility model content]

The purpose of the utility model is to overcome above-mentioned deficiency, provides a kind of its control range big, the optical receiving circuit that control precision is high.

The purpose of the utility model is to realize like this: it comprises photoelectric conversion unit (1), gain adjusting unit (3), sample processing unit (4); Its improvement is: also comprise radiofrequency signal amplifying unit (2) and computer processing unit (5); The signal output part of said photoelectric conversion unit (1) is electrically connected at the input of radiofrequency signal amplifying unit (2) and the input of sample processing unit (4) respectively; Convert light signal to the signal of telecommunication and export radiofrequency signal amplifying unit (2) to; Simultaneously, sample processing unit (4) is taked the signal of telecommunication of said photoelectric conversion unit (1) output; The output of said radiofrequency signal amplifying unit (2) is electrically connected at gain adjusting unit (3), exports the signal of telecommunication after amplifying to gain adjusting unit (3); The output of said sample processing unit (4) is electrically connected at the input of computer processing unit (5); The signal of telecommunication to taking carries out judgment processing, and exports computer processing unit (5) to through the A/D conversion, and the output of computer processing unit (5) is electrically connected at the control end of gain adjusting unit (3); The signal of telecommunication to sample processing unit (4) input carries out processing operations; Calculate the corresponding pad value of the signal of telecommunication, and export one and control signal to gain adjusting unit (3), the ride gain adjustment;

Said gain adjusting unit comprises by the 3rd diode (D3), the 4th diode (D4), the 5th diode (D5), the 6th diode (D6), the 4th inductance (L4); The 9th resistance (R9), the 11 resistance (R11); Wherein, The negative electrode of the 3rd diode (D3) is connected with the negative electrode of the 4th diode (D4); The negative electrode of the 5th diode (D5) is connected with the negative electrode of the 6th diode (D6), and the anode of the 3rd diode (D3) is connected with the anode of the 5th diode (D5), is connected with the 7th resistance (R7), the 8th resistance (R8) between the anode of the anode of the 4th diode (D4) and the 6th diode (D6) in turn; One end of the 9th resistance (R9) is connected with the 11 resistance (R11) end; The other end of the 9th resistance (R9) is connected in the node of the 7th resistance (R7) and the 8th resistance (R8), and another termination+12V voltage of the 11 resistance (R11), the node between the 3rd diode (D3) and the 5th diode (D5) are connected to the output of computer processor unit through the 4th inductance (L4); The node of the 7th resistance (R7) and the 4th diode (D4) is through the 19 electric capacity (C19) ground connection; Be connected the 22 electric capacity (C22) between the node of the 9th resistance (R9) and the tenth resistance (R10) and the earth terminal of the 19 electric capacity (C19); The node of the 8th resistance (R8) and the 6th diode (D6) is through the 20 electric capacity (C20) ground connection, is connected the tenth resistance (R10) between the node of the 9th resistance (R9) and the tenth resistance (R10) and the earth terminal of the 20 electric capacity (C20); Negative electrode warp the 18 electric capacity (C18) of the 3rd diode (D3) is connected in the output of the first order amplifying circuit of radiofrequency signal amplifying unit, and the node of the 3rd diode (D3) and the 18 electric capacity (C18) is through the 6th resistance (R6) ground connection; Negative electrode warp the 21 electric capacity (C21) of the 6th diode (D6) is connected in the input of the second level amplifying circuit of radiofrequency signal amplifying unit, and the node of the 6th diode (D6) and the 21 electric capacity (C21) is through the 12 resistance (R12) ground connection.

In the said structure; Said radiofrequency signal amplifying unit (2) comprises first order amplifying circuit (21), second level amplifying circuit (22) and transformation filter circuit (23); Described gain adjusting unit (3) is electrically connected between first order amplifying circuit (21) and the second level amplifying circuit (22), and transformation filter circuit (23) is electrically connected at the output of second level amplifying circuit (22).

The utility model beneficial effect is: the utility model converts light signal to the signal of telecommunication through photoelectric conversion unit, exports this signal of telecommunication to the radiofrequency signal amplifying unit and carries out the signal amplification, and the signal of telecommunication of process processing and amplifying exports gain adjusting unit to; Meanwhile, sample processing unit is taked the signal of telecommunication of photoelectric conversion unit output, and it is carried out the A/D conversion; Export computer processing unit to dc level signal; The corresponding pad value of this level signal is judged, calculated to computer processing unit to the level signal of sampling unit output, simultaneously, converts this pad value to a control signal and export gain adjusting unit to; Gain adjusting unit is carried out the decay of respective amplitude to the signal of telecommunication of radio frequency signal amplification unit circuit output; By this, make the level of the signal of telecommunication after decaying keep stable, the adjusting range of its gain adjusting unit is 0-20dB; The control range of the light signal corresponding with it also brings up to-8 to+2dBm; Satisfy all user's requests, control precision is high, and the signal of telecommunication of final output is more stable.

[description of drawings]

Fig. 1 is the theory diagram of the utility model

Fig. 2 is the schematic diagram of the utility model

[embodiment]

Below in conjunction with accompanying drawing and concrete execution mode the utility model is described further:

With reference to shown in Figure 1; The utility model has disclosed a kind of optical receiving circuit; It comprises photoelectric conversion unit 1, gain adjusting unit 3, sample processing unit 4; Also comprise radiofrequency signal amplifying unit 2 and computer processing unit 5, the signal output part of said photoelectric conversion unit 1 is electrically connected at the input of radiofrequency signal amplifying unit 2 and the input of sample processing unit 4 respectively, converts light signal to the signal of telecommunication and exports radiofrequency signal amplifying unit 2 to; Simultaneously, sample processing unit 4 is taked the signal of telecommunication of said photoelectric conversion unit 1 output; The output of said radiofrequency signal amplifying unit 2 is electrically connected at gain adjusting unit 3, exports the signal of telecommunication after amplifying to gain adjusting unit 3; The output of said sample processing unit 4 is electrically connected at the input of computer processing unit 5; The signal of telecommunication to taking carries out judgment processing, and changes the unit 5 that exports MICROCOMPUTER PROCESSING to through A/D, and the output of computer processing unit 5 is electrically connected at the control end of gain adjusting unit 3; The signal of telecommunication to sample processing unit 4 inputs carries out processing operations; Calculate the corresponding pad value of the signal of telecommunication, and export one and control signal to gain adjusting unit 3, the ride gain adjustment.

Radiofrequency signal amplifying unit 2 comprises first order amplifying circuit 21, second level amplifying circuit 22 and transformation filter circuit 23; Described gain adjusting unit 3 is electrically connected between first order amplifying circuit 21 and the second level amplifying circuit 22, and transformation filter circuit 23 is electrically connected at the output of second level amplifying circuit 22.

With reference to shown in Figure 2, light signal gets into the photocoupler (PIN pipe) in the photoelectric conversion unit 1, converts light signal to the signal of telecommunication, carries out the 3 pin output of RF impedance coupling back from transformer T1 through transformer T1; C1, R1, R2 form the sample conversion circuit, and C1 is a filter capacitor, and C2, C3, C4, R3 form filter circuit, and L1 and C6 play impedance fine setting effect to signal.Forming of sample processing unit 4 by singlechip chip U8, program input port J2 etc.; Singlechip chip U8 is through the signal sampling of port P0.6 to photoelectric conversion unit 1; Judge through singlechip chip U8 internal processes; Again through inner A/D conversion back output current signal to computer processing unit 5, when the inner A/D conversion of singlechip chip U8 output current produces pressure drop during to ground through resistance R 13, the resistance R 15 power takings resistance R13 force feed that powers on is gone into operational amplifier U7B and is carried out multiple and amplify; Through correlation computations formula in the operational amplifier calculate resistance R 14 and resistance R 16 resistance values; Operational amplifier U7A is to establish water circuit for the back level partly, but the sustaining voltage value is steady, and voltage signal exports the control end of gain adjusting unit 3 to through the output of operational amplifier U7A.

Gain adjusting unit 3 comprises by the 3rd diode (D3), the 4th diode (D4), the 5th diode (D5), the 6th diode (D6), the 4th inductance (L4); The 9th resistance (R9), the 11 resistance (R11); Wherein, The negative electrode of the 3rd diode (D3) is connected with the negative electrode of the 4th diode (D4); The negative electrode of the 5th diode (D5) is connected with the negative electrode of the 6th diode (D6), and the anode of the 3rd diode (D3) is connected with the anode of the 5th diode (D5), is connected with the 7th resistance (R7), the 8th resistance (R8) between the anode of the anode of the 4th diode (D4) and the 6th diode (D6) in turn; One end of the 9th resistance (R9) is connected with the 11 resistance (R11) end; The other end of the 9th resistance (R9) is connected in the node of the 7th resistance (R7) and the 8th resistance (R8), and another termination+12V voltage of the 11 resistance (R11), the node between the 3rd diode (D3) and the 5th diode (D5) are connected to the output of computer processor unit through the 4th inductance (L4); The node of the 7th resistance (R7) and the 4th diode (D4) is through the 19 electric capacity (C19) ground connection; Be connected the 22 electric capacity (C22) between the node of the 9th resistance (R9) and the tenth resistance (R10) and the earth terminal of the 19 electric capacity (C19); The node of the 8th resistance (R8) and the 6th diode (D6) is through the 20 electric capacity (C20) ground connection, is connected the tenth resistance (R10) between the node of the 9th resistance (R9) and the tenth resistance (R10) and the earth terminal of the 20 electric capacity (C20); Negative electrode warp the 18 electric capacity (C18) of the 3rd diode (D3) is connected in the output of the first order amplifying circuit of radiofrequency signal amplifying unit, and the node of the 3rd diode (D3) and the 18 electric capacity (C18) is through the 6th resistance (R6) ground connection; Negative electrode warp the 21 electric capacity (C21) of the 6th diode (D6) is connected in the input of the second level amplifying circuit of radiofrequency signal amplifying unit, and the node of the 6th diode (D6) and the 21 electric capacity (C21) is through the 12 resistance (R12) ground connection.The signal of computer processing unit 3 enters in the main signal through inductance L 4, and gain is adjusted to main signal, and adjusting range is 0-20dB; The 6th resistance R the 6, the 12 resistance R 12 in order to reduce the insertion loss, can be used big resistance as the bias circuit of Q1, Q2; Controllable voltage is than higher like this; Resistance R 7, R8, R9 are suitably selected its parameter as the build-out resistor of Q1, Q2, can be in big dynamic attenuation scope correct biasing and shunting be provided for series connection and bypass Q1, Q2; Make whole networking obtain impedance matching preferably; Capacitor C 19, C20 adjust flat permanent effect to the biasing circuit slight resistance, and resistance R 10, R11 are as the flat permanent bleeder circuit of whole gain adjusting unit 3 voltages (also can be defaulted as is gain starting point circuit), and capacitor C 18, C21 are capacitances.

In sum, the utility model converts light signal to the signal of telecommunication through photoelectric conversion unit 1, exports this signal of telecommunication to radiofrequency signal amplifying unit 2 and carries out signal and amplify; The signal of telecommunication through processing and amplifying exports gain adjusting unit 3 to, and meanwhile, sample processing unit 4 is taked the signal of telecommunication of photoelectric conversion unit 1 output; And it is carried out A/D transform, exporting computer processing unit 5 to dc level signal, the corresponding pad value of this level signal is judged, calculated to the level signal of 5 pairs of sample processing units of computer processing unit, 4 outputs; Simultaneously; Convert this pad value to a control signal and export gain adjusting unit 3 to, the signal of telecommunication of 3 pairs of radio frequency signal amplification unit 2 circuit outputs of gain adjusting unit carries out the decay of respective amplitude, by this; Make the level of the signal of telecommunication after decaying keep stable; The adjusting range of its gain adjusting unit 3 is 0-20dB, and the control range of the light signal corresponding with it also brings up to-8 to+2dBm, satisfies all user's requests; Control precision is high, and the signal of telecommunication of final output is more stable.

According to the announcement and the instruction of above-mentioned specification, those skilled in the art in the invention can also carry out suitable change and modification to above-mentioned execution mode.Therefore, the embodiment that discloses and describe above the present invention is not limited to also should fall in the protection range of claim of the present invention modifications more of the present invention and change.In addition, although used some specific terms in this specification, these terms are explanation for ease just, the present invention is not constituted any restriction.

Claims

1. optical receiving circuit; It comprises photoelectric conversion unit (1), gain adjusting unit (3), sample processing unit (4); It is characterized in that: also comprise radiofrequency signal amplifying unit (2) and computer processing unit (5); The signal output part of said photoelectric conversion unit (1) is electrically connected at the input of radiofrequency signal amplifying unit (2) and the input of sample processing unit (4) respectively; Convert light signal to the signal of telecommunication and export radiofrequency signal amplifying unit (2) to, simultaneously, sample processing unit (4) is taked the signal of telecommunication of said photoelectric conversion unit (1) output; The output of said radiofrequency signal amplifying unit (2) is electrically connected at gain adjusting unit (3), exports the signal of telecommunication after amplifying to gain adjusting unit (3); The output of said sample processing unit (4) is electrically connected at the input of computer processing unit (5); The signal of telecommunication to taking carries out judgment processing, and exports computer processing unit (5) to through the A/D conversion, and the output of computer processing unit (5) is electrically connected at the control end of gain adjusting unit (3); The signal of telecommunication to sample processing unit (4) input carries out processing operations; Calculate the corresponding pad value of the signal of telecommunication, and export one and control signal to gain adjusting unit (3), the ride gain adjustment;

2. optical receiving circuit according to claim 1; It is characterized in that: said radiofrequency signal amplifying unit (2) comprises first order amplifying circuit (21), second level amplifying circuit (22) and transformation filter circuit (23); Described gain adjusting unit (3) is electrically connected between first order amplifying circuit (21) and the second level amplifying circuit (22), and transformation filter circuit (23) is electrically connected at the output of second level amplifying circuit (22).