CN201204699Y - Feeding device with built-in modem - Google Patents
Feeding device with built-in modem Download PDFInfo
- Publication number
- CN201204699Y CN201204699Y CNU2008200454413U CN200820045441U CN201204699Y CN 201204699 Y CN201204699 Y CN 201204699Y CN U2008200454413 U CNU2008200454413 U CN U2008200454413U CN 200820045441 U CN200820045441 U CN 200820045441U CN 201204699 Y CN201204699 Y CN 201204699Y
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Abstract
The utility model discloses a feed imbedded with modulation-demodulation function, comprising: a first interface for receiving a control signal of the direct current and the control equipment in ascending or outputting a feedback signal of the antenna feeder system in descending; a modulation-demodulation circuit for modulating the control signal of the first interface in ascending and demodulating the feedback signal and outputting to the first interface in descending; a low-pass filter for filtering and outputting the demodulated control signal in ascending, and filtering the feedback signal and outputting to the modulation-demodulation circuit in descending; a second interface for receiving a radio frequency signal of the base station in ascending or outputting the radio frequency signal to the base station in descending; a third interface for synthesizing the direct current, the filtered control signal and the radio frequency signal and then outputting in ascending, outputting the feedback signal of the antenna feeder system to the low-pass filter and outputting the descending radio frequency signal to the second interface in descending. The utility model integrates the modulation-demodulation circuit and the feed, saves investment cost and is convenient for product modularization application.
Description
[technical field]
The utility model relates to a kind of loop of built-in modulation function, be applied between the base station system and antenna system of mobile communication, perhaps at base station system and tower amplifier, and the like the application scenario in, uplink/downlink signals is closed road/along separate routes.
[technical background]
In the mobile communication application, often need be or directly the lower decline angle of antenna system is regulated by tower amplifier, because tower amplifier and antenna system are higher apart from ground, the attendant is not easy to the maintenance of directly ascending a height, therefore, just require to provide equipment tower under and tower amplifier or antenna system to electrically connect, then by the adjustment process of the realization of the equipment under tower relevant parameter.
Realize in the tradition lower decline angle adjusting of antenna system is mainly contained dual mode.
First kind of mode is to connect a cable to the tower machine room lower from the antenna system of cat head or tower amplifier, electrically connect by external modulator-demodulator and controller, the adjusting that the attendant can be correlated with by controller at any time, the shortcoming of this mode is very obvious, the laying of cable causes increasing of equipment investment cost, and it is unfavorable that operator is caused.
The second way utilizes the plain edition loop to realize, in this mode, the base station that requires to electrically connect with loop has the modulation function.When up, the attendant controls on the base station, and the modulation by the base station inputs to loop with control signal, transfers to tower amplifier or antenna system by loop and base station radio-frequency signal and direct current after synthetic, just can realize the process of modulating; In like manner, when descending, the signal of antenna system or tower amplifier is shunted to control signal, radiofrequency signal and direct current through loop, and the correlation function module that enters the base station is carried out demodulation to control signal and got final product.For this mode, owing to need relevant functional module be set on the equipment of base station and so on, just limited the versatility of base station equipment, obviously do not meet the principle of modularized design.
[utility model content]
The purpose of this utility model will overcome above-mentioned deficiency exactly, and a kind of modularized design principle that meets is provided, and can make the reduce investment outlay loop of built-in modulation function of cost of operator.
For realizing this purpose, the utility model adopts following technical scheme:
The loop of a kind of built-in modulation function of the utility model comprises:
First interface, when up, receive direct current and control appliance control signal input or when descending the feedback signal of output antenna-feedback system;
Modulation-demodulation circuit is modulated to adapt to the call format of antenna-feedback system to signal the control signal of described first interface when up, when descending the feedback signal of antenna-feedback system is carried out exporting described first interface to after the demodulation;
Low pass filter carries out filtering output to the control signal after the modulation when up, when descending the feedback signal of antenna-feedback system is carried out exporting modulation-demodulation circuit to after the filtering;
Second interface, receive the input of base station radio-frequency signal when up or when descending the output radiofrequency signal give base station equipment;
The 3rd interface is exported after synthetic direct current, filtered control signal and the described radiofrequency signal when up, and the downlink time division road exports the feedback signal of antenna-feedback system to low pass filter and the radiofrequency signal that antenna-feedback system is descending exports second interface to.
Particularly, described modulation-demodulation circuit comprises:
Modulating unit is modulated signal when up;
Demodulating unit carries out demodulation to signal when descending;
Half-duplex device, the different conditions of corresponding upstream or downstream, described modulating unit of conducting or demodulating unit.
Described modulating unit comprises:
Signal source, generation is used for modulated carrier signal;
The analog switch module is modulated at the control signal of up time input on the carrier wave that described signal source produces;
Attenuation network, the signal that the analog switch module is exported carries out finishing modulation output after the power attenuation;
Described demodulating unit comprises:
The logarithm amplification detector, the feedback signal of the antenna-feedback system when descending carries out exporting after the demodulation;
Shaping circuit carries out shaping output to the feedback signal after the demodulation;
Be provided with an electric capacity between described second interface and the 3rd interface, this electric capacity carries out every straight-through friendship, suppresses low frequency signal the radiofrequency signal of upstream or downstream.
Described modulation-demodulation circuit and low pass filter all electrically connect with a lightning protection circuit.
Compared with prior art, the utility model possesses following advantage:
1, in loop, realized after the modulation function, the lower decline angle control appliance can directly be operated by loop, and need not lay the cable of special-purpose connection antenna-feedback system, thus, when realizing modularized design, can save the cost of investment of operator.
2, the modulating unit device used with respect to traditional ASK modulation circuit significantly reduces, and fixed the differential loss from the signal source to the output channel, makes that the power of output signal is highly stable; And can the power isolation of switch carrier signal be improved by adopting the high analog switch module of isolation, help reducing the interference of transmission course.
3, the traditional demodulation circuit generally is the combinational circuit that adopts diode detection pipe, operational amplifier and shaping comparator, and demodulating unit of the present utility model compares with it, and its advantage is that device count is few, and input dynamic range is wide, and the recovering signal distortion factor is little.
[description of drawings]
Fig. 1 is circuit theory diagrams of the present utility model;
Fig. 2 is the schematic diagram of modulation-demodulation circuit of the present utility model;
Fig. 3 is the circuit theory diagrams of low pass filter of the present utility model;
Fig. 4 is the circuit theory diagrams of lightning protection circuit of the present utility model.
[embodiment]
Below in conjunction with drawings and Examples the utility model is further described:
See also Fig. 1, the loop of built-in modulation function of the present utility model has three interfaces and modulation-demodulation circuit 12, lightning protection circuit 11, a low pass filter 13 and a capacitor C.
The first interface AISG, with base station (not shown), perhaps transfer controller (not shown) to be connected with electricity independently, and be connected with DC power supply, when up, receive direct current and control appliance control signal input or when descending the feedback signal of output antenna-feedback system to control appliance (base station or electricity are transferred controller).
Modulation-demodulation circuit 12 is modulated to adapt to the call format of antenna-feedback system to signal the control signal of the described first interface AISG when up, when descending the feedback signal of antenna-feedback system is carried out exporting the described first interface AISG to after the demodulation.
The concrete composition of modulation-demodulation circuit 12 sees Fig. 2 for details, specifically comprises, and modulating unit 3, demodulating unit 4 and half-duplex device 5, modulating unit 3 is used for when up signal being modulated; Demodulating unit 4 is used for when descending signal being carried out demodulation; The different conditions of half-duplex device 5 corresponding upstream or downstream, described modulating unit 3 of conducting or demodulating unit 4.
Modulating unit 3 is made up of IF signal source 31, analog switch module 32 and attenuation network 33.What analog switch module 32 was selected for use is the integrated chip with low internal resistance, high-isolation, high speed switch speed, it can be according to the quick switching channel selector switch of the high-low level of control signal, selecting by signal effectively is IF carrier wave or the signal ground that IF signal source 31 produces, and is the waveform modulated of control signal corresponding envelope signal; This envelope signal obtains the proper carrier wave power level by π type attenuation network 33 again, outputs on low-pass network and the feeder line, finishes modulated process.This circuit device more used than traditional ASK modulation circuit significantly reduces; And fixed differential loss from signal source 31 to output channel, make that the power of output signal is highly stable; And the isolation height of the analog switch device that adopts, the power isolation of switch carrier signal improves, and helps reducing the interference of transmission course.
Demodulating unit 4 is made up of logarithm amplification detector 41 and shaping circuit 42.Logarithm amplification detector 41 has adopted logarithmic amplifier, it is the function of corresponding level by linear transformation that logarithmic amplifier has input signal power, and the dynamic range of input signal is very big, can be effectively stably detects modulation signal according to the power of modulating wave envelope signal; Signal enters shaping circuit 42 after the detection, and circuit can be adjusted the comparative level of shaping circuit adaptively according to the input signal power level, makes that circuit can be that the 20dB input signal restores by the TTL signal form to dynamic range.The traditional demodulation circuit generally is the combinational circuit that adopts diode detection pipe, operational amplifier and shaping comparator, and this circuit compares with it, and its advantage is that device count is few, and input dynamic range is wide, and the recovering signal distortion factor is little.
Half-duplex device 5 main elements are monostable flipflops.Because the transmitting-receiving of antenna-feedback system control signal is to realize on same feeder line, so receiving and transmitting signal will transmit by time-multiplexed half-duplex form.Control switching circuit is realized the automatic conversion of receiving and transmitting signal transmission direction by adjusting the logic combination circuit of monostable burst length and switching controls.This circuit utilizes the characteristics of monostable flipflop, and according to the source automatic switching signal transmission direction of signal, it is simple and clear to have control logic, and reliable and stable characteristics can reduce extra direction control signal line, simplifies circuit design.
Consult Fig. 3, low pass filter 13 carries out filtering output to the control signal after the modulation when up, when descending the feedback signal of antenna-feedback system is carried out exporting modulation-demodulation circuit 12 to after the filtering and carries out demodulation.It is by 13 series connection of two-stage low pass filter, and prime constitutes second-order low-pass filter 13 by L1 and C1, has higher cut-off frequency, and the main radiofrequency signal that suppresses greater than 800MHz improves the isolation between radio-frequency channel and AISG signalling channel.Back level is about 10MHz by the cut-off frequency that L2, C2 and C3 constitute third-order low-pass filter 13, mainly suppresses crosstalking of low frequency signal on the cable, reduces the distortion of modulation signal.
Please consult Fig. 1 again, the second interface BTS/Node B is connected with base station radio-frequency equipment, receives the input of base station radio-frequency signal or output when descending when up.
The 3rd interface ANT/TMA is connected with antenna-feedback system on the tower by radio frequency cable, export after synthetic direct current, filtered control signal and the described radiofrequency signal when up, the downlink time division road exports the feedback signal of antenna-feedback system to low pass filter 13 and the radiofrequency signal that antenna-feedback system is descending exports the second interface BTS/Node B to.
Be provided with a capacitor C between described second interface BTS/Node B and the 3rd interface ANT/TMA, its main effect is to suppress low frequency signal, partition direct current, and frequency is transmitted by being coupling between these two interfaces of it to the radiofrequency signal of 2170MHz at 800MHz simultaneously.
Described modulation-demodulation circuit 12 and low pass filter 13 all electrically connect with a lightning protection circuit 11, see Fig. 4 for details, the design of lightning protection circuit 11 combines the lightning protection characteristics of active circuit and passive circuit, directly adopted the Lightning Protection of passive circuit from the first interface AISG interface to the direct current channel (passage Fig. 4 from IN to OUT) of low pass filter 13, respectively placing a gas discharge tube (GDT) near two input/output interface places (among Fig. 4 from IN and OUT two), only connect the power inductance coupling on the passage, the direct voltage loss is minimum, and this mode has been avoided the excessive problem of direct current loss that use resistance decoupling causes in traditional lightning protection circuit; Adopted the Lightning Protection of active circuit to this path of direct current regulation circuit (DC-DC) from the first interface AISG interface; in above-mentioned direct current channel, passed through first gas discharge tube (among Fig. 4 from IN) afterwards; adopt a powerful resistance to introduce power supply as decoupling resistance; connect a Transient Suppression Diode (TVS) behind the resistance and carry out the secondary lightning protection to ground; just be linked on the direct current regulation circuit then from resistance terminal; the resistance of this mode decoupling resistance is bigger; can significantly reduce the intensity of the surging signal of input next stage circuit; protect active circuit effectively, improved the lightning protection grade of device.
The operation principle of this loop is as described below.
During signal uplink, the antenna control signal that is input to the AISG interface from the base station is the form of RS485 bus signals, effect by modulating unit 3, this control signal is carried out on-off keying modulation (OOK) to the carrier signal of IF, the filtering by low-pass network together with direct current then, converge at the 3rd interface ANT/TMA again with from base station, the radiofrequency signal that is capacitively coupled to the 3rd interface ANT/TMA, three road signals are transported to base station cat head antenna-feedback system by radio frequency cable.
During signal downlink, import by the 3rd interface ANT/TMA, shunt to the second interface BTS/Node B and low pass filter 13 from the radiofrequency signal and the antenna-feedback system control signal of antenna-feedback system.The radiofrequency signal that is capacitively coupled to the second interface BTS/Node B is delivered to the radio frequency interface of base station, another road is filtered into the intermediate frequency Modulation ripple of belt controling signal through the signal of low pass filter 13, this modulating wave is through the demodulation of modulation-demodulation circuit 12, be reduced into the sky feedforward control signal of RS485 bus signals form, give the AISG control appliance of base station then.
Loop of the present utility model is compared maximum advantage, and to be that it has increased built-in with the plain edition loop The modulation-demodulation circuit 12 of intermediate frequency (IF) signal, therefore, except having the plain edition loop direct current Signal and radiofrequency signal are closed outside the function on road, also have antenna feeder equipment controling signal modulation and demodulation function. Modulation function: the antenna feeder equipment controling signal is modulated on the IF signal, closes the road with direct current and radio frequency letter then; Demodulation: intermediate-freuqncy signal is separated with radiofrequency signal, and demodulate control signal to antenna feeder equipment. So, Antenna-feedback system directly connects Smart type loop, can realize on base station and the tower by the radio-frequency feed cable The control connection mode of base station equipment and tower top device has been simplified in devices communicating and monitoring.
Claims (7)
1, a kind of loop of built-in modulation function is characterized in that comprising:
First interface, when up, receive direct current and control appliance control signal input or when descending the feedback signal of output antenna-feedback system;
Modulation-demodulation circuit is modulated to adapt to the call format of antenna-feedback system to signal the control signal of described first interface when up, when descending the feedback signal of antenna-feedback system is carried out exporting described first interface to after the demodulation;
Low pass filter carries out filtering output to the control signal after the modulation when up, when descending the feedback signal of antenna-feedback system is carried out exporting modulation-demodulation circuit to after the filtering;
Second interface, receive the input of base station radio-frequency signal when up or when descending the output radiofrequency signal give base station equipment;
The 3rd interface is exported after synthetic direct current, filtered control signal and the described radiofrequency signal when up, and the downlink time division road exports the feedback signal of antenna-feedback system to low pass filter and the radiofrequency signal that antenna-feedback system is descending exports second interface to.
2, the loop of built-in modulation function according to claim 1 is characterized in that: described modulation-demodulation circuit comprises:
Modulating unit is modulated signal when up;
Demodulating unit carries out demodulation to signal when descending;
Half-duplex device, the different conditions of corresponding upstream or downstream, described modulating unit of conducting or demodulating unit.
3, the loop of built-in modulation function according to claim 2 is characterized in that described modulating unit comprises:
Signal source, generation is used for modulated carrier signal;
The analog switch module is modulated at the control signal of up time input on the carrier wave that described signal source produces;
Attenuation network, the signal that the analog switch module is exported carries out finishing modulation output after the power attenuation;
4, the loop of built-in modulation function according to claim 2 is characterized in that described demodulating unit comprises:
The logarithm amplification detector, the feedback signal of the antenna-feedback system when descending carries out exporting after the demodulation;
Shaping circuit carries out shaping output to the feedback signal after the demodulation;
5, the loop of built-in modulation function according to claim 3 is characterized in that described demodulating unit comprises:
The logarithm amplification detector, the feedback signal of the antenna-feedback system when descending carries out exporting after the demodulation;
Shaping circuit carries out shaping output to the feedback signal after the demodulation;
6, according to the loop of any described built-in modulation function in the claim 1 to 5, it is characterized in that: be provided with an electric capacity between described second interface and the 3rd interface, this electric capacity carries out every straight-through friendship, suppresses low frequency signal the radiofrequency signal of upstream or downstream.
7, the loop of built-in modulation function according to claim 6 is characterized in that: described modulation-demodulation circuit and low pass filter all electrically connect with a lightning protection circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008200454413U CN201204699Y (en) | 2008-03-25 | 2008-03-25 | Feeding device with built-in modem |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008200454413U CN201204699Y (en) | 2008-03-25 | 2008-03-25 | Feeding device with built-in modem |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201204699Y true CN201204699Y (en) | 2009-03-04 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2008200454413U Expired - Lifetime CN201204699Y (en) | 2008-03-25 | 2008-03-25 | Feeding device with built-in modem |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201204699Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101257330B (en) * | 2008-03-25 | 2012-06-06 | 京信通信系统（中国）有限公司 | Feeding electric appliance embedded with modem function |
| CN103442461A (en) * | 2013-08-30 | 2013-12-11 | 江苏理工学院 | Electrically tunable antenna modulation-demodulation communication system |
-
2008
- 2008-03-25 CN CNU2008200454413U patent/CN201204699Y/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101257330B (en) * | 2008-03-25 | 2012-06-06 | 京信通信系统（中国）有限公司 | Feeding electric appliance embedded with modem function |
| CN103442461A (en) * | 2013-08-30 | 2013-12-11 | 江苏理工学院 | Electrically tunable antenna modulation-demodulation communication system |
| CN103442461B (en) * | 2013-08-30 | 2016-11-16 | 江苏理工学院 | Electrically tunable antenna modulation-demodulation communication system |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20090304 Effective date of abandoning: 20080325 |