CN200980077Y - A radio frequency controlling circuit - Google Patents
A radio frequency controlling circuit Download PDFInfo
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- CN200980077Y CN200980077Y CN 200620016573 CN200620016573U CN200980077Y CN 200980077 Y CN200980077 Y CN 200980077Y CN 200620016573 CN200620016573 CN 200620016573 CN 200620016573 U CN200620016573 U CN 200620016573U CN 200980077 Y CN200980077 Y CN 200980077Y
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- 230000008878 coupling Effects 0.000 claims description 23
- 238000010168 coupling process Methods 0.000 claims description 23
- 238000005859 coupling reaction Methods 0.000 claims description 23
- 238000001514 detection method Methods 0.000 abstract description 9
- 230000001174 ascending effect Effects 0.000 abstract 3
- 230000011514 reflex Effects 0.000 description 5
- 238000004891 communication Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000011144 upstream manufacturing Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000003467 diminishing effect Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
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Abstract
The utility model provides a radio-frequency control circuit, comprising a voltage-control attenuator, a differential amplifying circuit, an ascending couple detection circuit, and a descending couple detection circuit, wherein the ascending and the descending couple detection circuits are respectively connected with the input of the differential amplifying circuit, the voltage-control attenuator is connected with the output of the differential amplifying circuit. The utility model respectively samples and detects the ascending and the descending signals, adds two signals via a certain ratio, uses the added voltage as the control potential of the voltage-control attenuator, therefore, only needs one unit circuit to realize two functions as automatic potential control and open-circuit protection, with some advantage on cost control.
Description
Technical field
The utility model relates to a kind of radio frequency control circuit that is applicable to time division duplex wireless communication device.
Background technology
The 3G epoch are coming.The special advantages that more and more shows based on the communication mode of TDD (time division duplex).Its high spectrum utilization, stronger anti-multipath damping capacity etc. all are that its leadership in the future communications mode is laid a good foundation.
PHS, WLAN and TD-SCDMA etc. are at China's TDD communication mode of extensive use at present or in the near future.In the overlay network of these systems, need a lot of trunkings (as the repeater, trunk amplifier), carry out the covering and the relay of electromagnetic wave signal.Usually, especially when indoor distribution, when requiring within the specific limits the blasting of these trunkings, keep power output constant.Therefore, need in circuit, add ALC (automatic electric-level control) circuit.In addition, in project installation and equipment use, the situation that the antenna end mismatch is serious even open a way may appear, in this case, the signal overwhelming majority of power amplifier output all can be returned in antenna port reflects, cause the interference of downstream signal, even can burn the low noise amplifier in the up link data feedback channel.Therefore, also need in equipment, design open loop protection circuit.
Common way is ALC to be divided into different element circuits with open loop protection circuit to realize.Alc circuit is similar, and basic ideas all are to realize by output forward power sampling-detection-computing amplification-control voltage-controlled attenuator; And open-circuit-protection the most frequently used be to close amplifier power supply by its control circuit.Do like this, protected the parts in the equipment certainly, but after closing power amplifier, equipment can't be worked, and coverage hole occurs.
The utility model content
The technical problems to be solved in the utility model is, overcomes the deficiency that above-mentioned prior art exists, and a kind of radio frequency control circuit that possesses automatic electric-level control and open circuit protecting function simultaneously is provided.
For solving the problems of the technologies described above, the utility model provides a kind of radio frequency control circuit, comprise: voltage-controlled attenuator, differential amplifier circuit, up coupling detecting circuit and descending coupling detecting circuit, described up, descending coupling detecting circuit links to each other with the input of described differential amplifier circuit respectively, and described voltage-controlled attenuator links to each other with the output of described differential amplifier circuit.
The utlity model has following useful effect: upward signal and downstream signal are taken a sample respectively and detection after; with both according to certain ratio addition; then with the control level of the voltage after the addition as voltage-controlled attenuator; making only needs an element circuit; just can realize automatic electric-level control and two kinds of functions of open-circuit-protection, in cost control, also have certain advantage.
Description of drawings
Fig. 1 is the theory diagram of the utility model embodiment.
Fig. 2 is the electrical block diagram of the utility model embodiment.
Embodiment
Below in conjunction with accompanying drawing the utility model embodiment is described in detail.
Please refer to shown in Figure 1, the utility model embodiment radio frequency control circuit comprises voltage-controlled attenuator, differential amplifier circuit, up coupling detecting circuit and descending coupling detecting circuit, up, descending coupling detecting circuit links to each other with the input of differential amplifier circuit respectively, and voltage-controlled attenuator links to each other with the output of differential amplifier circuit.The input signal of antenna port transfers to up coupling detecting circuit by circulator, converts level signal to through the coupling detection, is input to the input of differential amplifier circuit, is labeled as V2; In like manner, descending output signal is through descending coupling detecting circuit coupling detection and be converted into level signal, is input to the input of differential amplifier circuit, is labeled as V3.Basic operation logic according to differential amplifier circuit, V0=Rf (V1/R1-V2/R2-V3/R3), wherein V0 is the output level of differential amplifier circuit, V1 is a reference level, therefore, as can be seen, under the situation that the multiplication factor and the reference level of differential amplifier circuit are determined, output level V0 is by incoming level V2, and V3 determines.That is to say; under the situation of even open circuit serious in situation (2) the antenna end mismatch of (1) equipment operate as normal; voltage-controlled attenuator plays the major control effect by (1) V3 (2) V2 respectively, thereby realizes that possessing automatic electric-level simultaneously with an element circuit controls (ALC) and open circuit protecting function.
Particularly, please refer to shown in Figure 2ly, be a preferred embodiment of the present utility model: the radio frequency control circuit that the preferred embodiment disclosed specifically comprises voltage-controlled attenuator, descending coupled microstrip line w2, detector diode D1, D2, amplifying circuit in the same way, differential amplifier circuit, circulator T, antenna port, up coupled microstrip line w1, amplitude limiter, isolator etc.Differential amplifier circuit comprises operational amplifier NA, and up amplifying circuit in the same way comprises operational amplifier NA2, and descending amplifying circuit in the same way comprises operational amplifier NA3.During downstream circuitry work, descending output signal flows to 2 ends of circulator T from the 1 end input of circulator T, and 2 ends are connected with antenna port; During upstream circuitry work, the input signal of antenna end flows to 3 ends by 2 ends of circulator T, and 3 ends are connected with upstream circuitry.It before 1 end of circulator T a descending coupling detecting circuit, comprise descending coupled microstrip line w2 and detector diode D2, following line output radiofrequency signal converts level signal to after the overcoupling detection, signal is again by after amplifying circuit amplifies in the same way, be input to the input of differential amplifier circuit, be labeled as V3; Be a up coupling circuit behind 3 ends of circulator T, comprise up coupled microstrip line w1 and detector diode D1, in like manner, after up input radio frequency signal amplifies by detection, be input to the input of differential amplifier circuit, be labeled as V2.The output of differential amplifier circuit is connected with voltage-controlled attenuator, controls the work of voltage-controlled attenuator by its output level V0.
The operating characteristic of present embodiment is: the incoming level of differential amplifier circuit is made up of descending level signal V3 and up level signal V2, basic operation logic according to differential amplifier circuit, with reference to accompanying drawing 2, can learn following logical relation: V0=Rf (V1/R1-V2/R2-V3/R3), wherein, V1 is a reference level, can regulate by potentiometer VR, this shows, under the situation that the multiplication factor and the reference level of differential amplifier circuit are determined, output level V0 is by incoming level V2, and V3 determines, that is to say that two level signals of up-downgoing are started to control simultaneously to make to voltage-controlled attenuator and used.Simultaneously because the degree of coupling of coupling microstrip and in the same way the multiplication factor of amplifier determine, so that the size of V2 and V3 is main is relevant with the size of the size of downstream circuitry output signal and upstream circuitry input signal.Under the situation of equipment operate as normal, the dried equipment of putting of PHS with 2W is example, the power of downlink signal is generally 33dB, the isolation of circulator is generally about 20dB, as seen the signal power that descending output signal reflexes to the data feedback channel input is very little, according to above-mentioned circuit logic relation and principle of operation: V0=Rf (V1/R1-V2/R2-V3/R3), because up input signal power is very little, under the prerequisite that other factors are determined, incoming level V2 is very little to the contribution of outputs level signals V0, can ignore, V0 mainly contains descending incoming level V3 and decides, at this time, circuit just can be seen an ALC (automatic electric-level control) loop (shown in frame of broken lines A among Fig. 2) as, by descending coupling detecting circuit descending output signal is carried out power detection, convert level signal V3 to, controlled the work of voltage-controlled attenuator again by V3, the formation in ALC loop guarantees the constant output of down going channel power with this.Under the situation of device antenna port open or serious mismatch, descending output signal almost completely reflexes to the input of data feedback channel, cause the interference of downstream signal, even can burn the low noise amplifier (up amplifying circuit) in the up link data feedback channel.The dried equipment of putting of PHS with 2W is example; the input signal power that reflexes to data feedback channel will reach more than the 30dB; and the maximal input of up low noise amplifier is generally below the 20dB; at this time; the formation in open-circuit-protection loop (shown in frame of broken lines B among Fig. 2) greatly reduces the probability that low noise amplifier is damaged.Because it is very big to reflex to the input signal power of data feedback channel, up incoming level signal V2 also increases thereupon, according to the logical relation in the above-mentioned control circuit: V0=Rf (V1/R1-V2/R2-V3/R3), V2 plays a decisive role in circuit to the contribution of whole output level V0, at this moment, voltage-controlled attenuator is realized a bigger decay under the main effect of V2, thereby reduce the power output of down going channel, the signal that reflexes to up input is also along with diminishing, simultaneously, we add an amplitude limiter before up input amplifier, better guaranteed the safety of up link.Concerning down link, we add an isolator behind descending amplification circuit output end, have so also effectively avoided because of interference and the damage of antenna port mismatch reflected signal to descending amplifying circuit.
The utility model embodiment only needs an element circuit, just can realize following function: in the equipment operate as normal, what circuit was mainly realized is automatic level control function, to guarantee the constant output of equipment; In the time of device antenna end open circuit or the serious mismatch of port; then play the effect of a protective circuit; adjusting by this open loop protection circuit; greatly reduce the probability that the up-downgoing amplifying circuit damages; simultaneously; down going channel can be turned off amplifier power supply, though the power output of transmitting terminal has reduced like this, equipment also can be realized certain network coverage.In addition, an element circuit is realized two kinds of functions, also has certain advantage in cost control.
Claims (8)
1, a kind of radio frequency control circuit, it is characterized in that: comprising: voltage-controlled attenuator, differential amplifier circuit, up coupling detecting circuit and descending coupling detecting circuit, described up, descending coupling detecting circuit links to each other with the input of described differential amplifier circuit respectively, and described voltage-controlled attenuator links to each other with the output of described differential amplifier circuit.
2, radio frequency control circuit according to claim 1 is characterized in that: also comprise circulator, link to each other with described up, descending coupling detecting circuit respectively that described circulator also links to each other with antenna port.
3, radio frequency control circuit according to claim 1 is characterized in that: also comprise up amplifying circuit in the same way and descending amplifying circuit in the same way, be connected between the input of described up, descending coupling detecting circuit and described differential amplifier circuit.
4, radio frequency control circuit according to claim 1 is characterized in that: comprise that also it is connected the input of described differential amplifier circuit in order to the potentiometer of reference level to be provided.
5, radio frequency control circuit according to claim 1 is characterized in that: described up coupling detecting circuit further comprises up coupled microstrip line and detector diode; Described descending coupling detecting circuit further comprises descending coupled microstrip line and detector diode.
6, radio frequency control circuit according to claim 1, it is characterized in that: also comprise up amplifying circuit and descending amplifying circuit, link to each other with described up, descending coupling detecting circuit respectively, the input of described descending amplifying circuit also links to each other with described voltage-controlled attenuator.
7, radio frequency control circuit according to claim 6 is characterized in that: the input of described up amplifying circuit also is connected with amplitude limiter.
8, radio frequency control circuit according to claim 6 is characterized in that: the output of described descending amplifying circuit also is connected with isolator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200620016573 CN200980077Y (en) | 2006-12-18 | 2006-12-18 | A radio frequency controlling circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200620016573 CN200980077Y (en) | 2006-12-18 | 2006-12-18 | A radio frequency controlling circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN200980077Y true CN200980077Y (en) | 2007-11-21 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200620016573 Expired - Fee Related CN200980077Y (en) | 2006-12-18 | 2006-12-18 | A radio frequency controlling circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN200980077Y (en) |
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2006
- 2006-12-18 CN CN 200620016573 patent/CN200980077Y/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20071121 Termination date: 20141218 |
|
| EXPY | Termination of patent right or utility model |