CN202978949U - Device for controlling signal power - Google Patents
Device for controlling signal power Download PDFInfo
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- CN202978949U CN202978949U CN 201220571595 CN201220571595U CN202978949U CN 202978949 U CN202978949 U CN 202978949U CN 201220571595 CN201220571595 CN 201220571595 CN 201220571595 U CN201220571595 U CN 201220571595U CN 202978949 U CN202978949 U CN 202978949U
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Abstract
The utility model discloses a device for controlling signal power. The device comprises a matching circuit module, a voltage controlled attenuator, a coupler, a radio frequency RF power detector, an error amplifier and an optical module. The input end of the matching circuit module accesses a radio frequency signal from a base station, and the output end is connected with the first input end of the voltage controlled attenuator. The second input end of the voltage controlled attenuator is connected with the first input end of the error amplifier. The output end of the voltage controlled attenuator is connected with the input end of the coupler. The first output end of the coupler is connected with the input end of the optical module. The second output end of the coupler is connected with the input end of the RF power detector. The output end of the RF power detector is connected with the first input end of the error amplifier. The second input end of the error amplifier is connected with a threshold value voltage. By using the device for controlling signal power, the working reliability of a fiber optic repeater can be improved.
Description
Technical field
The utility model relates to power control techniques, relates in particular to a kind of device of control signal power.
Background technology
For mobile communication, be no matter 2G or 3G communication, if high-quality service is provided, what at first need to solve is network coverage problem.Wherein, cost is low, flexibility good, installation is simple owing to having for optical fiber repeater, without many-sided advantages such as pilot pollutions, becomes the important component part of the technical scheme that solves the network coverage.
Optical fiber repeater is made of near-end repeater and far-end repeater, wherein, is connected by optical fiber between near-end repeater and far-end repeater, transmits with settling signal.be respectively arranged with radio frequency (RF in near-end repeater and far-end repeater, Radio Frequency) module and optical module, on down link, after wireless signal (signal of telecommunication) is coupled out from the base station, radio-frequency module processing by the near-end repeater, enter the near-end repeater, electric light conversion by optical module, after amplification, the signal of telecommunication changes light signal into, input to optical fiber from the near-end repeater, the process Optical Fiber Transmission is to the far-end repeater, the optical module of far-end repeater transfers the light signal that receives to the signal of telecommunication, and amplify, the signal of telecommunication that amplifies is sent into the radio-frequency module emission after ovennodulation, the coverage goal zone.Operation principle and the down link of up link are similar, the signal of telecommunication of mobile terminal emission is by the radio-frequency module of far-end repeater, enter the far-end repeater, by the electric light conversion of optical module, the signal of telecommunication changes light signal into, input to optical fiber from the far-end repeater, to the near-end repeater, the optical module of near-end repeater transfers the light signal that receives to the signal of telecommunication, amplifies through Optical Fiber Transmission, the signal of telecommunication that amplifies is sent into radio-frequency module and is launched after ovennodulation, thereby gets back to the base station.
In practical application, because the near-end repeater is nearer apart from the base station, thereby the near-end repeater is generally larger from the downstream signal power that antenna for base station is coupled to, and do not take to control the measure of downstream signal power, like this, it is saturated that the downstream signal of relatively high power may make the final amplifier in the optical module of near-end repeater occur, thereby produce distortion, cause network congestion and paralysis, even burn out and put the large device of final stage, make the communication system collapse, reduced the reliability of near-end repeater work; Further, excessive modulation signal also may affect the life-span of analog laser in the radio-frequency module of far-end repeater, even burns out analog laser, makes the functional reliability of far-end repeater lower.
The utility model content
Embodiment of the present utility model provides a kind of device of control signal power, improves the functional reliability of optical fiber repeater.
For achieving the above object, the device of a kind of control signal power that the utility model embodiment provides comprises: matching circuit module, voltage-controlled attenuator, coupler, radio frequency power detector, error amplifier and optical module, wherein,
The input access of matching circuit module is from the radiofrequency signal of base station, output is connected with the first input end of voltage-controlled attenuator, the second input of voltage-controlled attenuator is connected with the first output of error amplifier, the output of voltage-controlled attenuator is connected with the input of coupler, the first output of coupler is connected with the input of optical module, the second output of coupler is connected with the input of RF power detector, the output of RF power detector is connected with the first input end of error amplifier, and the second input of error amplifier is connected with threshold voltage.
Preferably, described device further comprise be connected with described error amplifier, according to the status signal of the second output output of error amplifier, the condition indication circuit module of the operating state of voltage-controlled attenuator being carried out corresponding indication.
Preferably, described matching circuit module comprises: the first inductor, the 7th electric capacity and the 8th electric capacity, wherein,
The radiofrequency signal of input accesses respectively an end of the first inductor and an end of the 7th electric capacity, and the other end of the first inductor is connected with an end of the 8th electric capacity, and the other end of the other end of the 7th electric capacity and the 8th electric capacity is ground connection respectively.
Preferably, described voltage-controlled attenuator comprises: the 3rd electric capacity, the 3rd resistance, the second photodiode PIN to, the first electric capacity, the first resistance, the 5th resistance, the 6th electric capacity, the 5th electric capacity, the second resistance, the second electric capacity, the 3rd PIN to, the 4th resistance, the 4th electric capacity, the 7th resistance, the 8th resistance, triode and the 6th resistance, wherein
One end of the 3rd electric capacity is connected with an end of the 8th electric capacity, and the other end is connected with an end of the 3rd resistance, the other end ground connection of the 3rd resistance;
The 2nd PIN is to comprising: the first diode and the second diode, the negative pole of the second diode is connected with the negative pole of the first diode and the other end of the 3rd electric capacity respectively, the positive pole of the first diode is connected with an end of the first electric capacity and an end of the first resistance respectively, the other end ground connection of the first electric capacity; The positive pole of the second diode is connected with an end of the 5th resistance;
The other end of the 5th resistance is connected with an end of the 6th electric capacity and an end of the 5th electric capacity respectively, and the access control level signal; The other end of the 6th electric capacity is connected with the other end of the 5th electric capacity and ground connection;
The 3rd PIN is to comprising: the 3rd diode and the 4th diode, the positive pole of the 3rd diode is connected with the positive pole of the second diode, the negative pole of the 3rd diode is connected with the negative pole of the 4th diode, the positive pole of the 4th diode is connected with an end of the second resistance and an end of the second electric capacity respectively, and the other end of the second resistance is connected with the other end of the first resistance; The other end ground connection of the second electric capacity;
One end of the 4th resistance is connected with the positive pole of the 3rd diode, other end ground connection;
One end of the 4th electric capacity is connected with an end of the 4th resistance, and the other end is connected with coupler;
One end of the 7th resistance is connected with the first reference voltage, and the other end is connected with an end of the 8th resistance, the other end ground connection of the 8th resistance;
The base stage of triode is connected with an end of the 8th resistance, and collector electrode is connected with the first reference voltage, and emitter is connected with the other end of the first resistance;
One end of the 6th resistance is connected with the other end of the first resistance, other end ground connection.
Preferably, described condition indication circuit module comprises: the first amplifier, the tenth electric capacity and the 20 resistance, wherein,
One end ground connection of the tenth electric capacity, another termination first reference voltage;
The first end output status signal of the first amplifier, the 4th end ground connection, the 8th termination the first reference voltage, the 3rd termination the second reference voltage, the second end is connected with an end of the 20 resistance R 20;
The other end of the 20 resistance is connected with error amplifier.
Preferably, described error amplifier comprises: the second amplifier, the 7th electric capacity, the 8th electric capacity, the 3rd inductance and the 21 resistance, wherein,
The 7th end of the second amplifier is connected with the other end of the 20 resistance, an end of the 7th electric capacity and an end of the 3rd inductance respectively, and five terminal connects the threshold voltage signal, and the 6th end is connected with the other end of the 7th electric capacity;
One end of the 21 resistance is connected with the 6th end of the second amplifier, and the other end is connected with coupler;
The other end of the 3rd inductance is connected with an end of the 8th electric capacity and the access control level signal, the other end ground connection of the 8th electric capacity.
Preferably, described RF power detector comprises: the 9th electric capacity, the 11 electric capacity, the 12 electric capacity, the 13 electric capacity and power detection chip, wherein,
One end ground connection of the 9th electric capacity, the other end is connected with the other end of the 21 resistance;
One end of the 11 electric capacity is connected with an end of the 12 electric capacity and ground connection, and the other end of the 11 electric capacity is connected with the other end of the 12 electric capacity and accesses the first reference voltage;
One end of the 13 electric capacity is connected with the other end of the 12 electric capacity, and the other end is connected with the second end of power detection chip;
First of power detection chip is connected with the other end of end the 12 electric capacity, and the 3rd end is connected with coupler, the 4th end ground connection, and five terminal access the first reference voltage, the 6th end is connected with the other end of the 9th electric capacity.
Preferably, described coupler comprises: the 19 resistance, and an end of the 19 resistance is connected with the other end and the optical module of the 4th electric capacity respectively, and the other end is connected with the 3rd end of power detection chip.
as seen from the above technical solution, the device of a kind of control signal power that the utility model embodiment provides, comprise: matching circuit module, voltage-controlled attenuator, coupler, the radio frequency power detector, error amplifier and optical module, wherein, the input access of matching circuit module is from the radiofrequency signal of base station, output is connected with the first input end of voltage-controlled attenuator, the second input of voltage-controlled attenuator is connected with the first output of error amplifier, the output of voltage-controlled attenuator is connected with the input of coupler, the first output of coupler is connected with the input of optical module, the second output of coupler is connected with the input of RF power detector, the output of RF power detector is connected with the first input end of error amplifier, the second input of error amplifier is connected with threshold voltage.Like this, by the mode of feedback is set, the radiofrequency signal of input near-end repeater is carried out power control, thereby the radiofrequency signal of avoiding exporting optical module to produces saturated phenomenon, and optical fiber repeater can be worked more reliably.
Description of drawings
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, below will do to introduce simply to the accompanying drawing of required use in embodiment or description of the Prior Art.Apparently, the accompanying drawing in below describing is only embodiment more of the present utility model, for those of ordinary skills, can also obtain according to these accompanying drawing illustrated embodiments other embodiment and accompanying drawing thereof.
Fig. 1 is the apparatus structure schematic diagram of the utility model embodiment control signal power.
Fig. 2 is the structural representation of the utility model embodiment matching circuit module and voltage-controlled attenuator.
Fig. 3 is the structural representation of the utility model embodiment condition indication circuit module, coupler, RF power detector and error amplifier.
Fig. 4 is the method flow schematic diagram of the utility model embodiment control signal power.
Embodiment
Below with reference to accompanying drawing, the technical scheme of each embodiment of the utility model is carried out clear, complete description, obviously, described embodiment is only a part of embodiment of the present utility model, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are resulting all other embodiment under the prerequisite of not making creative work, all belong to the scope that the utility model is protected.
Near-end repeater in existing optical fiber repeater, after carrying out from the downstream signal that antenna for base station is coupled to the impedance matching processing, export optical module to, after amplifying, final amplifier in optical module exports the far-end repeater to, because the near-end repeater is nearer apart from the base station, thereby, on down link, the near-end repeater is generally larger from the downstream signal power that antenna for base station is coupled to, and causes final amplifier to produce distortion, has reduced the functional reliability of near-end repeater; Further, the downstream signal of the relatively high power of near-end repeater output also affects life-span of analog laser in the radio-frequency module of far-end repeater, causes the functional reliability of far-end repeater also lower.
Automatic electric-level is controlled (ALC, Automatic Level Control) effect of technology is when input signal power during less than the power threshold that sets in advance, automatic level control circuit cuts little ice to input signal, output signal power and the sexual intercourse of input signal power retention wire; When input signal power during greater than the power threshold that sets in advance, automatic level control circuit is controlled input signal, output power signal is limited under the power threshold that sets in advance, make the output signal power by automatic level control circuit be no more than power threshold, thereby keep the stable of output signal.
In existing near-end repeater, do not possess automatic level control function, simultaneously do not have the special chip of ready-made integrated automatic level control function to use yet, more not do not possess the chip of compatible applicability for different communication modulation systems and frequency range (for example, GSM/CDMA etc.), thereby, make the input signal of reception in the situation that power is larger, can not carry out power to it and control, the signal saturated phenomenon easily occur, cause the functional reliability of optical fiber repeater lower.
Therefore, in the utility model embodiment, a kind of device of control signal power is proposed, adopt automatic level control circuit, the signal of input near-end repeater is carried out power control, thereby the signal of avoiding exporting optical module to produces saturated phenomenon, and optical fiber repeater can be worked more reliably.
Below take down link as example, embodiment is described in detail to the utility model, and the utility model embodiment that it should be noted that also can arrange in the far-end repeater automatic level control circuit, and being applied to up link, the handling process of its handling process and down link is similar.
Fig. 1 is the apparatus structure schematic diagram of the utility model embodiment control signal power.Referring to Fig. 1, this device is the near-end repeater, comprising: matching circuit module, voltage-controlled attenuator, coupler, RF power detector, error amplifier and optical module, wherein,
The input access of matching circuit module is from the radiofrequency signal of base station, output is connected with the first input end of voltage-controlled attenuator, the second input of voltage-controlled attenuator is connected with the first output of error amplifier, the output of voltage-controlled attenuator is connected with the input of coupler, the first output of coupler is connected with the input of optical module, the second output of coupler is connected with the input of RF power detector, the output of RF power detector is connected with the first input end of error amplifier, and the second input of error amplifier is connected with threshold voltage;
Matching circuit module is used for the radiofrequency signal that is coupled to from antenna for base station is carried out impedance matching, and the radiofrequency signal that will carry out impedance matching exports voltage-controlled attenuator to;
In the utility model embodiment, input matching module is used for realizing the impedance matching that rf input port is good.
Voltage-controlled attenuator is used for the control level signal according to error amplifier output, the attenuation of the radiofrequency signal of control group coupling, and the radiofrequency signal of processing to the coupler output attenuatoin;
In the utility model embodiment, voltage-controlled attenuator is according to the control level signal of exporting after the error amplifier comparison process, control the attenuation of the signal (radiofrequency signal of impedance matching) of matching circuit module output, thereby the amplitude to output signal is controlled, to the radiofrequency signal of coupler output attenuatoin processing.
Coupler, the radiofrequency signal through attenuation processing that is used for receiving exports optical module to, and the radiofrequency signal through attenuation processing that receives is coupled, and obtains coupled power signal, exports the RF power detector to;
In the utility model embodiment, coupler is connected with voltage-controlled attenuator output, the signal that is used for receiving separates, and the radiofrequency signal of the attenuation processing of voltage-controlled attenuator output is coupled, and exports the coupled power signal portion of energy to the RF power detector and carry out power detection.
The RF power detector, the coupled power signal that is used for receiving is converted to voltage signal, exports error amplifier to;
In the utility model embodiment, the RF power detector can be selected peak detection or average detection according to the practical application needs, and the coupled power signal that coupler is exported converts voltage signal to.
Error amplifier be used for to receive the voltage signal of RF power detector output, compare with the voltage threshold that sets in advance, and compared result carries out integral operation, generates the control level signal, exports voltage-controlled attenuator to by the first output;
In the utility model embodiment, the magnitude of voltage of error amplifier comparison RF power detector output and the voltage threshold (magnitude of voltage of threshold voltage) that sets in advance, comparative result is carried out integral operation, to voltage-controlled attenuator output control signal, to control voltage-controlled attenuator to the attenuation of the radiofrequency signal of the impedance matching of reception.
Optical module is used for the radiofrequency signal through attenuation processing of coupler output is modulated on light carrier to transmit.
In the utility model embodiment, optical module will be modulated on light carrier and transmit through the radiofrequency signal (RF signal) of attenuation processing, and is identical with the prior art processing, specifically can referring to the correlation technique document, not repeat them here.
In the utility model embodiment, voltage-controlled attenuator, coupler, RF power detector and error amplifier form automatic level control circuit, the signal of input near-end repeater is carried out power control, and produce saturated phenomenon with the signal of avoiding exporting optical module to.
Preferably, near-end can further include in the repeater: the condition indication circuit module,
Error amplifier is further used for according to comparative result, determines the operating state of voltage-controlled attenuator, generates status signal, exports the condition indication circuit module to by the second output;
In the utility model embodiment, error amplifier also can carry out integration to state information and amplify, and certainly, in practical application, can be also to amplify and the control level signal that carries out low-pass filtering is determined the operating state of voltage-controlled attenuator according to integration.
The condition indication circuit module is used for the status signal according to the second output output of error amplifier, and the operating state of voltage-controlled attenuator is carried out corresponding indication.
In the utility model embodiment, the condition indication circuit module is according to the status signal of error amplifier output, carry out the operating state indication, for example, when determining that voltage-controlled attenuator is not decayed to the radiofrequency signal of impedance matching, the status signal of error amplifier output is used for the indicator light of state of a control indicating circuit module and closes; When determining that the radiofrequency signal of voltage-controlled attenuator to impedance matching decays, the indicator light in the status signal state of a control indicating circuit module of error amplifier output is opened, and the attenuation processing to input signal is carried out in expression.
The below is described the workflow of device shown in Figure 1.
the matching circuit module received RF signal, carry out exporting voltage-controlled attenuator to after impedance matching, voltage-controlled attenuator is connected with coupler and error amplifier respectively, according to the control level signal that receives, to the radiofrequency signal through impedance matching of input decay control after, export coupler to, coupler is coupled to the radiofrequency signal through attenuation processing that receives, a part of power signal of coupling exports the RF power detector to, the RF power detector converts the coupled power signal that receives to voltage signal, export the negative phase end (the 6th input) of error amplifier to, the threshold voltage signal that the positive terminal of error amplifier (the 5th input) access sets in advance, the threshold voltage signal can pass through microcontroller (MCU, Micro Control Unit) digital-to-analogue (DA, Digital to Analogue) transducer produces, also can be obtained by the variable resistance dividing potential drop.
Integrating amplification circuit in error amplifier, after the difference of voltage signal and threshold voltage signal is carried out integration, amplification processing, after carrying out low-pass filtering by the low pass filter in error amplifier, controlled level signal (V
Ctrl), export voltage-controlled attenuator to, be used for controlling the operating state of voltage-controlled attenuator.Simultaneously, the difference signal that will carry out integration, amplifies after processing exports the condition indication circuit module to, is used to indicate the current operating state of voltage-controlled attenuator.
Simultaneously, coupler will export optical module to and modulate through the radiofrequency signal of attenuation processing, and be modulated on optical signal carrier and transmit.
Wherein,
Automatic level control circuit adopts the mode of rear feed, namely be coupled by the signal of coupler to voltage-controlled attenuator output, coupled power signal exports the RF power detector to, be converted to analog voltage signal through the RF power detector, by comparing with the threshold voltage signal, after its difference is carried out integration, amplification processing, the output control level signal V that obtains
CtrlBe used for controlling the attenuation of voltage-controlled attenuator.
Like this, realize the control of automatic level control circuit attenuation by voltage-controlled attenuator, radiofrequency signal exports voltage-controlled attenuator to after carrying out impedance matching by matching circuit module, and voltage-controlled attenuator is by the control level signal V from error amplifier
Ctrl, control the attenuation through the radiofrequency signal of impedance matching, thereby control the amplitude of output signal (radiofrequency signal of attenuation processing).
Fig. 2 is the structural representation of the utility model embodiment matching circuit module and voltage-controlled attenuator.Referring to Fig. 2,
Matching circuit module comprises: the first inductor L1, the 7th capacitor C 7 and the 8th capacitor C 8, wherein,
The radiofrequency signal of input accesses respectively the end of the first inductor L1 and an end of the 7th capacitor C 7, and the other end of the first inductor L1 is connected with an end of the 8th capacitor C 8, and the other end of the other end of the 7th capacitor C 7 and the 8th capacitor C 8 is ground connection respectively.
In the utility model embodiment, the first inductor L1, the 7th capacitor C 7 and the 8th capacitor C 8 form π type match circuit, can realize input port impedance matching preferably.
according to photodiode (PIN, Positive-intrinsic-negative) RF impedance is the characteristic that changes with curent change, in the utility model embodiment, voltage-controlled attenuator adopts π type attenuator, combination by 4 PIN pipe (two PIN to) realizes, comprise: the 3rd capacitor C 3, the 3rd resistance R 3, the second photodiode (PIN, Positive-intrinsic-negative) to D2, the first capacitor C 1, the first resistance R 1, the 5th resistance R 5, the 6th capacitor C 6, the 5th capacitor C 5, the second resistance R 2, the second capacitor C 2, the 3rd PIN is to D3, the 4th resistance R 4, the 4th capacitor C 4, the 7th resistance R 7, the 8th resistance R 8, triode Q1 and the 6th resistance R 6, wherein,
One end of the 3rd capacitor C 3 is connected with an end of the 8th capacitor C 8, and the other end is connected with an end of the 3rd resistance R 3, the other end ground connection of the 3rd resistance R 3;
The 2nd PIN comprises D2: the first diode and the second diode, the negative pole of the second diode is connected with the negative pole of the first diode and the other end of the 3rd capacitor C 3 respectively, the positive pole of the first diode is connected with an end of the first capacitor C 1 and an end of the first resistance R 1 respectively, the other end ground connection of the first capacitor C 1; The positive pole of the second diode is connected with an end of the 5th resistance R 5;
The other end of the 5th resistance R 5 is connected with an end of the 6th capacitor C 6 and an end of the 5th capacitor C 5 respectively, and access control level signal V
CtrlThe other end of the 6th capacitor C 6 is connected with the other end of the 5th capacitor C 5 and ground connection;
The 3rd PIN comprises D3: the 3rd diode and the 4th diode, the positive pole of the 3rd diode is connected with the positive pole of the second diode, the negative pole of the 3rd diode is connected with the negative pole of the 4th diode, the positive pole of the 4th diode is connected with an end of the second resistance R 2 and an end of the second capacitor C 2 respectively, and the other end of the second resistance R 2 is connected with the other end of the first resistance R 1; The other end ground connection of the second capacitor C 2;
One end of the 4th resistance R 4 is connected with the positive pole of the 3rd diode, other end ground connection;
One end of the 4th capacitor C 4 is connected with an end of the 4th resistance R 4, and the other end is connected with coupler;
One end of the 7th resistance R 7 is connected with the first reference voltage (5V), and the other end is connected with an end of the 8th resistance R 8, the other end ground connection of the 8th resistance R 8;
The base stage of triode Q1 is connected with an end of the 8th resistance R 8, and collector electrode is connected with the first reference voltage (5V), and emitter is connected with the other end of the first resistance R 1;
One end of the 6th resistance R 6 is connected with the other end of the first resistance R 1, other end ground connection.
preferably, the capacitance of the 3rd capacitor C 3 and the 4th capacitor C 4 is respectively 100 pico farads (pF), the resistance of the 3rd resistance R 3 and the 4th resistance R 4 is respectively 620 ohm, the resistance of the 7th resistance R 7 is 1000 ohm, the resistance of the 8th resistance R 8 is 560 ohm, the resistance of the first resistance R 1 and the second resistance R 2 is respectively 2200 ohm, the capacitance of the first capacitor C 1 and the second capacitor C 2 is respectively 1 nanofarad, the resistance of the 6th resistance R 6 is 1000 ohm, the resistance of the 5th resistance R 5 is 390 ohm, the capacitance of the 6th capacitor C 6 is 1 nanofarad (1nF), the capacitance of the 5th capacitor C 5 is 100 nanofarads.
In the utility model embodiment, preferably, the PIN pipe is to selecting the HSMP38XX of Agilent, HSMP38XX has good Linearity at 800MHZ～2.2G working frequency range, thereby, by the voltage-controlled attenuator of this PIN pipe to consisting of, have that differential loss is little, large bandwidth, high Linearity and an advantage such as low-cost.Specifically, voltage-controlled attenuator adopts two right advantages of PIN pipe to have:
At first, because the maximum isolation degree of attenuator network is that PIN pipe by series connection determines, adopts two PIN to manage right, can improve the maximum of decay, or under certain attenuation, upper frequency limit be doubled;
The second, two PIN pipe makes the nonlinear properties of even-order be offset to the 180 anti-phase work of degree;
The 3rd, the attenuator network of formation is symmetrical, and biasing circuit is very simple, and cost is low.
In the utility model embodiment, in order further to reduce fixedly Insertion Loss and the impedance matching of voltage-controlled attenuator, can increase the resistance of the 3rd resistance R 3 and the 4th resistance R 4, but due to the increase along with the resistance of the 3rd resistance R 3 and the 4th resistance R 4, the control level signal (V that needs
Ctrl) amplitude is also larger, thereby in the utility model embodiment, the resistance of the 3rd resistance R 3 and the 4th resistance R 4 is set to 620 ohm, the resistance of the 5th resistance R 5 is set to 390 ohm; The resistance of the first resistance R 1 and the second resistance R 2 is set to 2.2K ohm.
Triode Q1 in attenuator network, the 7th resistance R 7 and the 8th resistance R 8 are used to following branch road that a stable 1.2V bias reference voltage is provided, thereby the resistance of the 7th resistance R 7 is set to 1K ohm, and the resistance of the 8th resistance R 8 is set to 560 ohm.
The 3rd capacitor C 3 and the 4th C4 are direct-current coupling electric capacity, can adjust its capacitance according to the optical module working frequency range.
It should be noted that and the value of each components and parts in the utility model embodiment near-end repeater can adjust accordingly according to actual needs follow-up repeating no more by optimized algorithm.
Fig. 3 is the structural representation of the utility model embodiment condition indication circuit module, coupler, RF power detector and error amplifier.Referring to Fig. 3,
The condition indication circuit module comprises: the first amplifier U8A, the tenth capacitor C 10 and the 20 resistance R 20, wherein,
One end ground connection of the tenth capacitor C 10, another termination first reference voltage (5V);
The first end output status signal of the first amplifier U8A, the 4th end ground connection, the 8th termination the first reference voltage (5V), the 3rd termination reference voltage (V
REF), the second end is connected with an end of the 20 resistance R 20;
The other end of the 20 resistance R 20 is connected with error amplifier.
In the utility model embodiment, preferably, the capacitance of the tenth capacitor C 10 is 100 nanofarads, and the resistance of the 20 resistance R 20 is 10K ohm.
Error amplifier comprises: the second amplifier U8B, the 7th capacitor C 7, the 8th capacitor C 8, the 3rd inductance L 3 and the 21 resistance R 21, wherein,
The 7th end of the second amplifier U8B is connected with the other end of the 20 resistance R 20, an end of the 7th capacitor C 7 and an end of the 3rd inductance L 3 respectively, and five terminal connects the threshold voltage signal, and the 6th end is connected with the other end of the 7th capacitor C 7;
One end of the 21 resistance R 21 is connected with the 6th end of the second amplifier U8B, and the other end is connected with coupler;
The other end of the 3rd inductance L 3 is connected with an end of the 8th capacitor C 8 and the access control level signal, the other end ground connection of the 8th capacitor C 8.
In the utility model embodiment, the 3rd inductance L 3 and the 8th capacitor C 8 consist of low pass filter, are used for obtaining control level signal (V
Ctrl).The capacitance of the 7th capacitor C 7 is 100 nanofarads, and the capacitance of the 8th capacitor C 8 is 1 nanofarad, and the resistance of the 21 resistance R 21 is 10K ohm, and the inductance value of the 3rd inductance L 3 is 100 nanohenrys (nH).
The RF power detector comprises: the 9th capacitor C 9, the 11 capacitor C 11, the 12 capacitor C 12, the 13 capacitor C 13 and power detection chip U9, wherein,
One end ground connection of the 9th capacitor C 9, the other end is connected with the other end of the 21 resistance R 21;
One end of the 11 capacitor C 11 is connected with an end of the 12 capacitor C 12 and ground connection, and the other end of the 11 capacitor C 11 is connected with the other end of the 12 capacitor C 12 and accesses the first reference voltage (5V);
One end of the 13 capacitor C 13 is connected with the other end of the 12 capacitor C 12, and the other end is connected with the second end of power detection chip U9;
First of power detection chip U9 is connected with the other end of end the 12 capacitor C 12, and the 3rd end is connected with coupler, the 4th end ground connection, and five terminal access the first reference voltage (5V), the 6th end is connected with the other end of the 9th capacitor C 9.
In the utility model embodiment, preferably, power detection chip U9 can adopt chip ADL5XXX.
The capacitance of the 9th capacitor C 9 is 100 nanofarads, and the capacitance of the 11 capacitor C 11 is 100 nanofarads, and the capacitance of the 12 capacitor C 12 is 100 pico farads, and the capacitance of the 13 capacitor C 13 is 1 nanofarad.
Coupler comprises: an end of the 19 resistance R 19, the 19 resistance R 19 is connected with the other end and the optical module of the 4th capacitor C 4 respectively, and the other end is connected with the 3rd end of power detection chip U9.
In the utility model embodiment, coupler is connected with voltage-controlled attenuator output, adopts the 19 resistance R 19 to be coupled, and can reduce costs on the one hand; On the other hand, the resistance value size can change for the intensity of adjusting the RF signal after taking a sample, and simultaneously, resistance value remains in certain scope, and output impedance is only had slight impact.Like this, the RF signal (coupled power signal) of sampling part is delivered to the RF power detector, converts coupled power signal to voltage signal by the RF power detector.
Deliver to the negative phase end (the 6th end) of error amplifier through the voltage signal after the conversion of RF power detector, the reference voltage of its positive terminal (five terminal) for arranging, be threshold voltage, threshold voltage can be produced by the DA of MCU, also can be obtained by the variable resistance dividing potential drop.In the utility model embodiment, threshold voltage produces by the DA mode of MCU, in practical application, and can be by the output voltage values that change DA is set of MCU.
Error amplifier (integrating amplification circuit) operational amplifier used can adopt LM2904D.After the integration amplification of comparative result (voltage signal is poor with the threshold voltage signal that sets in advance) by integrating amplification circuit, the output signal of error amplifier is control level signal (V by low pass filter
Ctrl), be used for controlling the work of voltage-controlled attenuator, wherein, the 3rd inductance L 3 and the 8th capacitor C 8 consist of low pass filters, are used for HFS and other interference signals of filtering RF signal; The value of the 3rd inductance L 3 and the 8th capacitor C 8 can be according to the actual conditions adjustment.
Simultaneously, the comparator in the output voltage input state indicating circuit module of error amplifier is with the reference voltage (V that sets in advance
REF) compare, its output is used to refer to the operating state of alc circuit.
The utility model embodiment is when normal operation, when radiofrequency signal power larger, voltage signal and the voltage threshold difference in error amplifier by the output of RF power detector is less, after carrying out integral operation through error amplifier, the integrated value that obtains is just less, like this, the voltage-controlled attenuator decay is just larger, thereby effectively reduce radiofrequency signal power, the signal that guarantees to export optical module to avoids waveform saturated in normal range (NR).
In practical application, the level of RF signals critical point of near-end repeater optical module input can be arranged on the 0dBm place; When the radiofrequency signal power of input changed between 0～10dBm, its signal errors that exports optical module to can be controlled in 0 ± 1dBm scope; Further, the near-end repeater is operated under the closed loop state, can still can stablize under the conditions such as variations in temperature, device aging, work accurately; And, can be according to laser input modulating signal power requirement in optical module, and the rear class input power requires to adjust the maximum signal level of output and the thresholding of input signal.
By as seen above-mentioned, the device of the control signal power of the utility model embodiment, optical module with respect to existing near-end repeater is operated under the large-signal input condition, can affect the stability of near-end repeater operation, reduce the working life of components and parts in optical module, even can damage the situation of post-amplifier and laser, by automatic level control circuit is set, namely adopt discrete component to consist of voltage-controlled attenuator, make it possess the characteristics such as adjustable extent is large, distortion is little, bandwidth, low cost; In error amplifier, adopt integrating circuit as the difference amplifying circuit of feedback loop simultaneously, its slope is large, and control precision is high; Further, this automatic level control circuit also can possess the indication of alc circuit operating state; And; the ALC input threshold (voltage threshold) of this automatic level control circuit can be adjusted according to actual needs; can be applied to the different frequency ranges such as GSM/CDMA/WCDMA; realize preferably the input protection function, can satisfy broadband, adjustable range is large, distortion is little, isolation is high, the high requirement of precision.Specifically, its useful technique effect mainly contain following some:
1, by discrete device parameter configuration in the change error amplifier, can realize that the automatic electric-level of multiband is controlled;
2, by voltage-controlled attenuator, can realize that adjustable range is large, distortion is little, isolation is high;
3, control precision is high: can satisfy when 0～10dBm radiofrequency signal is inputted, output signal remains in 0 ± 1dBm scope; When inputting less than 0dBm RF signal, keep linear increment or the relation of successively decreasing between output signal and input signal;
When 4, large-signal (greater than 10dBm) was inputted, the radiofrequency signal performance number of voltage-controlled attenuator output was adjustable;
5, show the ALC operating state.
6, moderate modulation signal can guarantee the life-span of analog laser in the radio-frequency module of far-end repeater, promotes the functional reliability of far-end repeater.
Fig. 4 is the method flow schematic diagram of the utility model embodiment control signal power.Referring to Fig. 4, the method is applied to near-end repeater, especially down link, comprising:
Step 401 receives the radiofrequency signal that is coupled to from antenna for base station, carries out impedance matching;
In this step, matching circuit module carries out impedance matching to the radiofrequency signal that is coupled to from antenna for base station, and the radiofrequency signal that will carry out impedance matching exports voltage-controlled attenuator to.
Step 402 according to the control level signal of feedback, is carried out attenuation to the radiofrequency signal of carrying out impedance matching and is controlled;
In this step, voltage-controlled attenuator is according to the control level signal of error amplifier output, the attenuation of the radiofrequency signal of control group coupling, and the radiofrequency signal of processing to the coupler output attenuatoin.
In the utility model embodiment, the power positive correlation of the attenuation of control level signal controlling and radiofrequency signal.The power that is radiofrequency signal is larger, and control level signal controlling voltage-controlled attenuator is also larger to the attenuation of the radiofrequency signal of input.
Step 403, the signal that will carry out attenuation control is coupled, and the road signal that is coupled is modulated on light carrier transmits;
In this step, what coupler will receive exports optical module to through a road of the radiofrequency signal of attenuation processing.
Step 404 is converted to voltage signal with another road signal that is coupled, and compare with the voltage threshold that sets in advance, and compared result is carried out integral operation, the control level signal of generation conduct feedback.
In this step, another road through the radiofrequency signal of attenuation processing that coupler will receive is coupled, obtain coupled power signal, export the RF power detector to, another road signal that the RF power detector will be coupled is converted to voltage signal, export error amplifier to, error amplifier compares the voltage signal that receives and the voltage threshold that sets in advance, obtain both differences, after carrying out integration, amplification processing, and carry out becoming the control level signal after low-pass filtering, export the voltage-controlled attenuator control that decays to.
Preferably, the method further comprises:
Step 405, according to comparative result, the operating state of the voltage-controlled attenuator controlled of determining to decay generates status signal, and the operating state of voltage-controlled attenuator is carried out corresponding indication.
In this step, comparative result is voltage signal and the difference of the voltage threshold that sets in advance, if difference in the difference range that sets in advance, indicates the state of voltage-controlled attenuator for being in not operating state; If difference exceeds the difference range that sets in advance, the state of indicating voltage-controlled attenuator is in running order.Certainly, in practical application, comparative result can be also other forms, for example, both and.
Obviously, those skilled in the art can carry out various changes and modification and not break away from spirit and scope of the present utility model the utility model.Like this, if of the present utility model these are revised and within modification belongs to the scope of the utility model claim and equivalent technologies thereof, the utility model also comprises these changes and modification interior.
Claims (8)
1. the device of a control signal power, is characterized in that, this device comprises: matching circuit module, voltage-controlled attenuator, coupler, radio frequency power detector, error amplifier and optical module, wherein,
The input access of matching circuit module is from the radiofrequency signal of base station, output is connected with the first input end of voltage-controlled attenuator, the second input of voltage-controlled attenuator is connected with the first output of error amplifier, the output of voltage-controlled attenuator is connected with the input of coupler, the first output of coupler is connected with the input of optical module, the second output of coupler is connected with the input of RF power detector, the output of RF power detector is connected with the first input end of error amplifier, and the second input of error amplifier is connected with threshold voltage.
2. device according to claim 1, it is characterized in that, described device further comprise be connected with described error amplifier, according to the status signal of the second output output of error amplifier, the condition indication circuit module of the operating state of voltage-controlled attenuator being carried out corresponding indication.
3. device according to claim 2, is characterized in that, described matching circuit module comprises: the first inductor, the 7th electric capacity and the 8th electric capacity, wherein,
The radiofrequency signal of input accesses respectively an end of the first inductor and an end of the 7th electric capacity, and the other end of the first inductor is connected with an end of the 8th electric capacity, and the other end of the other end of the 7th electric capacity and the 8th electric capacity is ground connection respectively.
4. device according to claim 3, it is characterized in that, described voltage-controlled attenuator comprises: the 3rd electric capacity, the 3rd resistance, the second photodiode PIN to, the first electric capacity, the first resistance, the 5th resistance, the 6th electric capacity, the 5th electric capacity, the second resistance, the second electric capacity, the 3rd PIN to, the 4th resistance, the 4th electric capacity, the 7th resistance, the 8th resistance, triode and the 6th resistance, wherein
One end of the 3rd electric capacity is connected with an end of the 8th electric capacity, and the other end is connected with an end of the 3rd resistance, the other end ground connection of the 3rd resistance;
The 2nd PIN is to comprising: the first diode and the second diode, the negative pole of the second diode is connected with the negative pole of the first diode and the other end of the 3rd electric capacity respectively, the positive pole of the first diode is connected with an end of the first electric capacity and an end of the first resistance respectively, the other end ground connection of the first electric capacity; The positive pole of the second diode is connected with an end of the 5th resistance;
The other end of the 5th resistance is connected with an end of the 6th electric capacity and an end of the 5th electric capacity respectively, and the access control level signal; The other end of the 6th electric capacity is connected with the other end of the 5th electric capacity and ground connection;
The 3rd PIN is to comprising: the 3rd diode and the 4th diode, the positive pole of the 3rd diode is connected with the positive pole of the second diode, the negative pole of the 3rd diode is connected with the negative pole of the 4th diode, the positive pole of the 4th diode is connected with an end of the second resistance and an end of the second electric capacity respectively, and the other end of the second resistance is connected with the other end of the first resistance; The other end ground connection of the second electric capacity;
One end of the 4th resistance is connected with the positive pole of the 3rd diode, other end ground connection;
One end of the 4th electric capacity is connected with an end of the 4th resistance, and the other end is connected with coupler;
One end of the 7th resistance is connected with the first reference voltage, and the other end is connected with an end of the 8th resistance, the other end ground connection of the 8th resistance;
The base stage of triode is connected with an end of the 8th resistance, and collector electrode is connected with the first reference voltage, and emitter is connected with the other end of the first resistance;
One end of the 6th resistance is connected with the other end of the first resistance, other end ground connection.
5. device according to claim 4, is characterized in that, described condition indication circuit module comprises: the first amplifier, the tenth electric capacity and the 20 resistance, wherein,
One end ground connection of the tenth electric capacity, another termination first reference voltage;
The first end output status signal of the first amplifier, the 4th end ground connection, the 8th termination the first reference voltage, the 3rd termination the second reference voltage, the second end is connected with an end of the 20 resistance R 20;
The other end of the 20 resistance is connected with error amplifier.
6. device according to claim 5, is characterized in that, described error amplifier comprises: the second amplifier, the 7th electric capacity, the 8th electric capacity, the 3rd inductance and the 21 resistance, wherein,
The 7th end of the second amplifier is connected with the other end of the 20 resistance, an end of the 7th electric capacity and an end of the 3rd inductance respectively, and five terminal connects the threshold voltage signal, and the 6th end is connected with the other end of the 7th electric capacity;
One end of the 21 resistance is connected with the 6th end of the second amplifier, and the other end is connected with coupler;
The other end of the 3rd inductance is connected with an end of the 8th electric capacity and the access control level signal, the other end ground connection of the 8th electric capacity.
7. device according to claim 6, is characterized in that, described RF power detector comprises: the 9th electric capacity, the 11 electric capacity, the 12 electric capacity, the 13 electric capacity and power detection chip, wherein,
One end ground connection of the 9th electric capacity, the other end is connected with the other end of the 21 resistance;
One end of the 11 electric capacity is connected with an end of the 12 electric capacity and ground connection, and the other end of the 11 electric capacity is connected with the other end of the 12 electric capacity and accesses the first reference voltage;
One end of the 13 electric capacity is connected with the other end of the 12 electric capacity, and the other end is connected with the second end of power detection chip;
First of power detection chip is connected with the other end of end the 12 electric capacity, and the 3rd end is connected with coupler, the 4th end ground connection, and five terminal access the first reference voltage, the 6th end is connected with the other end of the 9th electric capacity.
8. device according to claim 7, is characterized in that, described coupler comprises: the 19 resistance, and an end of the 19 resistance is connected with the other end and the optical module of the 4th electric capacity respectively, and the other end is connected with the 3rd end of power detection chip.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220571595 CN202978949U (en) | 2012-11-01 | 2012-11-01 | Device for controlling signal power |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220571595 CN202978949U (en) | 2012-11-01 | 2012-11-01 | Device for controlling signal power |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104065408A (en) * | 2014-06-18 | 2014-09-24 | 重庆三峡学院 | Satellite signal repeater |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104065408A (en) * | 2014-06-18 | 2014-09-24 | 重庆三峡学院 | Satellite signal repeater |
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