CN101505174A - Interface circuit and method for suppressing electromagnetic interference - Google Patents
Interface circuit and method for suppressing electromagnetic interference Download PDFInfo
- Publication number
- CN101505174A CN101505174A CNA2008100081037A CN200810008103A CN101505174A CN 101505174 A CN101505174 A CN 101505174A CN A2008100081037 A CNA2008100081037 A CN A2008100081037A CN 200810008103 A CN200810008103 A CN 200810008103A CN 101505174 A CN101505174 A CN 101505174A
- Authority
- CN
- China
- Prior art keywords
- interface circuit
- filter
- electromagnetic interference
- high frequency
- secondary coil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Abstract
The embodiment of the invention discloses an interface circuit and a method for inhibiting electromagnetic interference, which relate to interface circuits of communication equipment, and are mainly used for equipment such as ADSL and ISDN performing communication through copper wire loops. The interface circuit for inhibiting electromagnetic interference comprises a transformer, the transformer comprises a primary coil and a secondary coil, the secondary coil is provided with an intermediate tap, and the intermediate tap is earthed through a high frequency filter. The method for inhibiting electromagnetic interference conducts high frequency noise to an earthing point through the high frequency filter on the intermediate tap of the secondary coil of the transformer, thereby filtering the high frequency noise. The interface circuit and the method solve the problem that an interface circuit of the prior communication equipment has weaker electromagnetic interference inhibition function.
Description
Technical field
The present invention relates to interface circuit of communication equipment, particularly have the interface circuit that suppresses electromagnetic interference function in the communication equipment, and this interface circuit suppresses the method for electromagnetic interference.
Background technology
On existing copper loops, adopt general digital transmission technology, can make the Digital Transmission speed of most copper loops reach 9.6kbits even 28.8kbit/s; If adopt DSL (Digital Subscriber Loop) technology, can make the Digital Transmission speed of copper loops can reach the rank of MHz.
In order in copper loops, to realize full-duplex operation (being that transmitting channel and receive channel are worked simultaneously), modulator-demodulator is divided into passband the channel of two separation, be respectively applied for uplink communication and downlink communication, and use clawback bucking circuit, final by a transformer, the data of uplink communication and the data of downlink communication are aggregated on a pair of twisted-pair feeder, transmit.As shown in Figure 1, with the DSL technology is example, when dsl device sends signal, at first digital signal is converted into discrete analog signal by the DA conversion, through filter the radio-frequency component in the analog signal is filtered again, after obtaining analog signal, successively by Echo Cancellation circuit and transformer, output on the copper cash at last again.When the copper loops received signal, analog signal is earlier successively by transformer and Echo Cancellation circuit, the decoder module by chip internal is a digital signal with analog signal conversion then.Decoder module in DA modular converter that sends the signal use and received signal use all may produce high frequency noise, and these high frequency noises can cause electromagnetic interference to equipment.Signal also may be introduced a lot of high frequency noises by in the copper loops transmission course, and for example: the high-frequency signal that thunderbolt produces can be coupled on the copper loops.At present, the measure of inhibition electromagnetic interference than effective method is: add filter on signal circuit.Adsl port circuit block diagram as shown in Figure 1, input coil at transformer passes through capacitor C 1, C3 ground connection, or between transformer and Echo Cancellation circuit by capacitor C 2, C4 ground connection, so just high-frequency signal can be guided to earth terminal by capacitor C 1, C3 and C2, C4, suppress the electromagnetic interference that high-frequency signal causes equipment.
The inventor is in realizing process of the present invention, and there are the following problems at least to find the technology of above-mentioned inhibition high-frequency signal:
1, when selecting capacitor C 2, C4, need consider the port Impedance of Echo Cancellation circuit, when the noise signal of importing is strong, then need the capacitance of capacitor C 2, C4 is configured to more than the 100pF, noise signal can be filtered out.Because the capacitance of C2, C4 is bigger, promptly the resistance value of C2, C4 is less, has increased the frequency range that C2, C4 filtering are acted on, and makes the useful signal of part be filtered out by capacitor C 2, causes the signal loop performance obviously to descend.
2, the input coil of transformer is by capacitor C 1, C3 ground connection, because the impedance over the ground of Echo Cancellation circuit is lower, so, the earth terminal of capacitor C 1, C3 is equivalent to be connected to the port of Echo Cancellation circuit, that is, capacitor C 1, C3 are equivalent to be connected across between the input coil and output winding of transformer.Because capacitor C 1, C3 are less for the impedance of high-frequency signal, make high-frequency signal be coupled on the copper loops by capacitor C 1, C3, and outside surge (as thunderbolt) is coupled in the equipment that uses this interface circuit by capacitor C 1, C3 easily, cause the isolation performance of transformer to descend, cause electromagnetic interference stronger.
Summary of the invention
Embodiments of the invention provide a kind of interface circuit and method that suppresses electromagnetic interference, suppress the electromagnetic interference of transmission of digital signals in the copper loops, and guarantee the isolation performance and the loop performance of this interface circuit.
For achieving the above object, embodiments of the invention adopt following technical scheme:
A kind of interface circuit that suppresses electromagnetic interference comprises transformer, and this transformer comprises primary coil and secondary coil, and described secondary coil is provided with centre tap, and described centre tap is by high frequency filter ground connection.
A kind of method that suppresses electromagnetic interference is characterized in that, will pass through high frequency filter ground connection by the centre tap of transformer secondary output coil; High frequency noise outputs to earth terminal by described high frequency filter.
By the described embodiments of the invention of technique scheme, by centre tap being set at secondary coil, utilize high-frequency ripple device with centre tap ground connection then, make the high frequency noise that enters into secondary coil be directed to earth terminal by high frequency filter, prevented that high frequency noise is imported in the equipment at this interface circuit place, thereby suppressed electromagnetic interference.Simultaneously owing to do not have in the embodiment of the invention directly to pass through capacity earth at the input of transformer, make noise signal can not be coupled on the copper loops, outside surge (as thunderbolt) signal can not be coupled in the equipment that uses this interface circuit yet, has increased the isolation performance of this interface circuit; And the embodiment of the invention is not directly passed through capacity earth at the output of transformer, has prevented that useful signal is filtered, thereby has guaranteed the loop performance of this interface circuit.
Description of drawings
In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art, to do one to the accompanying drawing of required use in embodiment or the description of the Prior Art below introduces simply, apparently, accompanying drawing in describing below only is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other embodiment according to the accompanying drawing of these embodiment.
Fig. 1 is an adsl port circuit block diagram in the prior art;
Fig. 2 is the schematic diagram of interface circuit in the embodiment of the invention;
Fig. 3 is the impedance model figure of Fig. 2 equivalence;
Fig. 4 suppresses the flow chart of the method embodiment of electromagnetic interference for the present invention;
Fig. 5 suppresses the interface circuit first embodiment physical circuit figure of electromagnetic interference for the present invention;
Fig. 6 is the physical circuit figure of the active high-pass filter in the first embodiment of the invention;
Fig. 7 suppresses the interface circuit second embodiment physical circuit figure of electromagnetic interference for the present invention;
Fig. 8 is the signal graph that collects when adopting the existing interface circuit;
The signal graph that collects behind the embodiment of Fig. 9 for employing interface circuit of the present invention;
Figure 10 is the schematic diagram that interface circuit adopts band pass filter in the embodiment of the invention;
Figure 11 is the physical circuit figure of the active band-pass filter that interface circuit adopts in the embodiment of the invention;
Figure 12 is the schematic diagram that interface circuit adopts low pass filter in the embodiment of the invention;
Figure 13 is the physical circuit figure of the active low-pass filter that interface circuit adopts in the embodiment of the invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that is obtained under the creative work prerequisite.
The embodiment of the invention is passed through high frequency filter ground connection at the centre tap place of transformer secondary output coil, make high frequency noise be filtered, suppressed electromagnetic interference, according to employed occasion difference, transformer can comprise one group of primary coil, also can comprise many group primary coils, in the embodiment of the invention not the group number to primary coil limit.
As shown in Figure 2, this interface circuit passes through high frequency filter ground connection at the C of secondary coil point place, like this, the A point just is equivalent to by inductance and the high frequency filter ground connection of A point to this section of C point, and the B point just is equivalent to by inductance and the high frequency filter ground connection of B point to this section of C point.A point and the impedance over the ground of B point are exactly the impedance (as shown in Figure 3) after C1 and the high frequency filter series connection, because high frequency filter can intercept useful signal, and conducting high frequency noise signal, the high frequency noise that makes all arrive 2 of A, B all can be directed to earth terminal, prevented that high frequency noise is imported into the drive circuit that connects later, thereby the signal of guaranteeing to be input to drive circuit can not influence the service behaviour of drive circuit.
The method of inhibition electromagnetic interference is specially as shown in Figure 4 in the embodiment of the invention:
401, in secondary coil tap place of interface transformer, by high frequency filter ground connection.
402, useful signal and high frequency noise are coupled to secondary coil by the primary coil of transformer simultaneously, after high frequency noise is coupled to secondary coil, high frequency filter by secondary coil centre tap place is conducting to earth point, thereby has suppressed the influence that transformer follow-up circuit can not be subjected to high frequency noise.
Below in conjunction with accompanying drawing the embodiment that the present invention suppresses the interface circuit of electromagnetic interference is described in detail.
Embodiment 1:
As shown in Figure 5, in the present embodiment, be provided with two secondary coils on the transformer of interface circuit, a primary coil, a secondary coil is a transmit port, and another secondary coil is a receiving port, and the middle part of two secondary coils all is in series with capacitance, so the two ends of capacitance all need by filter capacitor ground connection, as the C1 among Fig. 5, C2, C3 and C4.In the present embodiment, a signal end 1 of transmit port is by the distributed capacitance between 1 and 3 on the secondary coil, and filter capacitor C3 ground connection, makes the high frequency noise that arrives this signal end 1 be directed to earth terminal.
In like manner, another signal end 4 of transmit port, and the high frequency noise that two signal ends (5 and 8) of receiving port are located also is directed to earth terminal.Present embodiment has prevented that high frequency noise is imported into the chip that this interface circuit connects, thereby the signal of guaranteeing to be input to chip can not influence the service behaviour of this chip.
The appearance value of above-mentioned filter capacitor C3 should could guarantee to filter out preferably the high frequency noise signal more than or equal to 100pF.When filter capacitor C3 value is 100pF, the noise signal more than the frequency range 100MHz can be filtered out, when filter capacitor C3 value was 1000pF, can be 30MHz with frequency range filters out to the noise signal of 100MHz.
The filter capacitor C3 that is adopted in the present embodiment is a kind of of mimic high pass filter, can also adopt other mimic high pass filter, and mimic high pass filter commonly used at present comprises: the active high-pass filter that resistance, electric capacity and operational amplifier are formed.As shown in Figure 5, the second order active high-pass filter for realizing by capacitance resistance and operational amplifier.
Interface circuit described in the foregoing description can be used in the equipment that communicates by copper loops, comprises ADSL access device, ISDN (Integrated Service Digital Network, integrated services digital network) access device etc.
Embodiment 2:
As shown in Figure 7, be provided with two secondary coils on the transformer of present embodiment interface circuit, a primary coil, a secondary coil is a transmit port, another secondary coil is a receiving port, but only is in series with capacitance at the middle part of transmit port secondary coil.For transmit port, the two ends of capacitance all need by filter capacitor (C5 and C6) ground connection, and receiving port only need pass through a filter capacitor C7 ground connection just at the middle part of coil.
The same with the principle among the embodiment 1, present embodiment has prevented that high frequency noise is imported into the chip that this interface circuit connects, thereby the signal of guaranteeing to be input to chip can not influence the service behaviour of this chip.
By experimental measurement can draw adopt the embodiment of the invention after, can weaken the high frequency noise of this interface circuit, as shown in Figure 8, be the spectrogram that adopts interface circuit of the prior art to measure, wherein abscissa is a frequency, and ordinate is a signal strength signal intensity, can be observed by Fig. 8, noise at 35MHz, 71MHz and 141MHz place is apparent in view, may cause electromagnetic interference.After adopting interface circuit embodiment of the present invention, remove to measure spectrogram again, obtain result shown in Figure 9, can see, the noise at 35MHz, 71MHz and 141MHz place obviously reduces a lot, and the range of decrease probably has 5dB to 10dB, has suppressed electromagnetic interference preferably.
All adopt mimic high pass filter as high frequency filter among the foregoing description 1 and the embodiment 2, when practice, analog band-pass filter can also be used as high frequency filter, only need make the frequency of high frequency noise signal drop on interior the getting final product of passband of analog band-pass filter.As shown in figure 10, the most general implementation of analog band-pass filter is exactly the analog band-pass filter that inductance L 1 and capacitor C 10 are formed.Also can pass through the active band-pass filter that resistance, electric capacity and operational amplifier are formed, be a second order active band-pass filter as shown in figure 11.
When described capacitance is positioned at the point midway of secondary coil, can be with simulation low-pass filter as high frequency filter; When perhaps not having capacitance in the secondary coil, directly centre tap is arranged on the point midway of secondary coil, then centre tap is passed through simulation low-pass filter ground connection.Because when signal transmitted, what transmitted at the two ends of secondary coil was differential signal, the midpoint current potential of secondary coil is zero so, can not be subjected to the influence of ground connection; If when the design simulation low pass filter, make the frequency of high frequency noise signal drop in the passband, then can make the high frequency noise signal be conducting to earth point, guarantee that the high frequency noise signal can not continue to transmit on holding wire.As shown in figure 12, the most general implementation of simulation low-pass filter is exactly an inductance L 2, certainly, also can pass through the active low-pass filter that resistance, electric capacity and operational amplifier are formed, and Figure 13 is a second order active low-pass filter.
Embodiment 3:
The high frequency filter that is adopted in the present embodiment is different from the high frequency filter that is adopted among embodiment 1 and the embodiment 2.All be to adopt analog filter in embodiment 1 and embodiment 2, when practice, can replace analog filter with digital filter.
Generally speaking, digital filter is by DSP (Digital Signal Processing) chip, and corresponding program is finished, detailed process is as follows: at first signal is carried out FFT conversion (fast fourier transform), then with the signal times after the conversion with a frequency factor, so that the unwanted frequency filtering signals is fallen, carry out DFT conversion (anti-fast fourier transform) at last again, the signal that obtains exporting.
If above-mentioned frequency factor is selected the high-pass equipment factor, then can realize digital high-pass filter; If select tape leads to frequency factor, then can realize digital band-pass filter.
Identical with the utilization principle of simulation low-pass filter, when described capacitance is positioned at the point midway of secondary coil, can be with wave digital lowpass filter as high frequency filter; When perhaps not having capacitance in the secondary coil, directly centre tap is arranged on the point midway of secondary coil, then centre tap is passed through wave digital lowpass filter ground connection.And wave digital lowpass filter is frequency factor need be chosen as the lowpass frequency factor to get final product.
Owing to do not have in the embodiment of the invention directly to pass through capacity earth at the input of transformer, make noise signal can not be coupled on the copper loops, outside surge (as thunderbolt) signal can not be coupled in the equipment that uses this interface circuit yet, has increased the isolation performance of this interface circuit; And the embodiment of the invention is not directly passed through capacity earth at the output of transformer, has prevented that useful signal is filtered, thereby has guaranteed the loop performance of this interface circuit.
Be appreciated that the implementation of passing through to change high frequency filter in the embodiments of the invention, still can finish purpose of the present invention, increase the isolation performance of interface circuit, and prevented that useful signal is filtered, thereby guaranteed the loop performance of this interface circuit.
The embodiment of the invention mainly is used in the interface circuit of various electronic equipments, particularly is used in the interface circuit of the electronic equipment that communicates by copper loops, for example: ADSL, ISDN etc.
The above; only be the specific embodiment of the present invention, but protection scope of the present invention is not limited thereto, any those of ordinary skill in the art are in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.
Claims (10)
1, a kind of interface circuit that suppresses electromagnetic interference comprises transformer, and this transformer comprises primary coil and secondary coil, it is characterized in that, described secondary coil is provided with centre tap, and described centre tap is by high frequency filter ground connection.
2, the interface circuit of inhibition electromagnetic interference according to claim 1 is characterized in that, the middle part of described secondary coil is in series with capacitance, and described centre tap is drawn respectively by the two ends of capacitance.
3, the interface circuit of inhibition electromagnetic interference according to claim 1 and 2 is characterized in that, described high frequency filter is digital filter or analog filter.
4, the interface circuit of inhibition electromagnetic interference according to claim 3 is characterized in that, described digital filter comprises digital high-pass filter or digital band-pass filter; Described analog filter comprises mimic high pass filter or analog band-pass filter.
5, the interface circuit of inhibition electromagnetic interference according to claim 4 is characterized in that, described mimic high pass filter comprises filter capacitor, and described analog band-pass filter comprises the electric capacity and the inductance of series connection.
6, the interface circuit of inhibition electromagnetic interference according to claim 1 is characterized in that, described centre tap is positioned at the point midway of secondary coil, and described high frequency filter is simulation low-pass filter or wave digital lowpass filter.
7, the interface circuit of inhibition electromagnetic interference according to claim 2 is characterized in that, described capacitance is positioned at the point midway of secondary coil, and described high frequency filter is simulation low-pass filter or wave digital lowpass filter.
According to the interface circuit of claim 6 or 7 described inhibition electromagnetic interference, it is characterized in that 8, described simulation low-pass filter comprises inductance.
9, the interface circuit of inhibition electromagnetic interference according to claim 1 is characterized in that, described transformer comprises two groups of secondary coils, and wherein one group of secondary coil is a transmit port, and another group secondary coil is a receiving port.
10, a kind of method that suppresses electromagnetic interference is characterized in that, with the centre tap of transformer secondary output coil by high frequency filter ground connection; High frequency noise outputs to earth terminal by described high frequency filter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2008100081037A CN101505174A (en) | 2008-02-04 | 2008-02-04 | Interface circuit and method for suppressing electromagnetic interference |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2008100081037A CN101505174A (en) | 2008-02-04 | 2008-02-04 | Interface circuit and method for suppressing electromagnetic interference |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101505174A true CN101505174A (en) | 2009-08-12 |
Family
ID=40977274
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2008100081037A Pending CN101505174A (en) | 2008-02-04 | 2008-02-04 | Interface circuit and method for suppressing electromagnetic interference |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101505174A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015058403A1 (en) * | 2013-10-25 | 2015-04-30 | 华为技术有限公司 | Copper wire interface circuit |
| CN107112813A (en) * | 2014-10-27 | 2017-08-29 | 高通股份有限公司 | Wireless power multi-coil mutual inductance removing method and device |
| CN110198584A (en) * | 2019-06-24 | 2019-09-03 | 山东中大电源科技有限公司 | A kind of one-way power carrier wave LED light adjusting system |
| CN110671098A (en) * | 2019-09-25 | 2020-01-10 | 中国科学院地质与地球物理研究所 | Underground single-core bus circuit device while drilling |
| CN110690765A (en) * | 2019-10-11 | 2020-01-14 | 哈尔滨工业大学 | High-speed full-duplex wireless energy data synchronous transmission system based on frequency division multiplexing |
| CN115986963A (en) * | 2022-01-20 | 2023-04-18 | 荣耀终端有限公司 | Wireless charging transmitting terminal, charging base and system |
-
2008
- 2008-02-04 CN CNA2008100081037A patent/CN101505174A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015058403A1 (en) * | 2013-10-25 | 2015-04-30 | 华为技术有限公司 | Copper wire interface circuit |
| US9742463B2 (en) | 2013-10-25 | 2017-08-22 | Huawei Technologies Co., Ltd. | Copper wire interface circuit |
| CN107112813A (en) * | 2014-10-27 | 2017-08-29 | 高通股份有限公司 | Wireless power multi-coil mutual inductance removing method and device |
| CN107112813B (en) * | 2014-10-27 | 2020-07-14 | 高通股份有限公司 | Wireless power multi-coil mutual inductance elimination method and device |
| CN110198584A (en) * | 2019-06-24 | 2019-09-03 | 山东中大电源科技有限公司 | A kind of one-way power carrier wave LED light adjusting system |
| CN110671098A (en) * | 2019-09-25 | 2020-01-10 | 中国科学院地质与地球物理研究所 | Underground single-core bus circuit device while drilling |
| CN110690765A (en) * | 2019-10-11 | 2020-01-14 | 哈尔滨工业大学 | High-speed full-duplex wireless energy data synchronous transmission system based on frequency division multiplexing |
| CN110690765B (en) * | 2019-10-11 | 2023-03-24 | 哈尔滨工业大学 | High-speed full-duplex wireless energy data synchronous transmission system based on frequency division multiplexing |
| CN115986963A (en) * | 2022-01-20 | 2023-04-18 | 荣耀终端有限公司 | Wireless charging transmitting terminal, charging base and system |
| CN115986963B (en) * | 2022-01-20 | 2024-04-19 | 荣耀终端有限公司 | Wireless charging transmitting terminal, charging base and system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101567120B1 (en) | Alien interference removal in vectored dsl | |
| CN107105366B (en) | Multi-channel echo cancellation circuit and method and intelligent device | |
| CA2577489C (en) | Interference cancellation system | |
| EP1095463B1 (en) | Suppression of rfi and impulse noise in communications channels | |
| CN101505174A (en) | Interface circuit and method for suppressing electromagnetic interference | |
| CN102859954B (en) | Signal transmitting apparatus | |
| WO1998018211A1 (en) | Appliance adapted for power line communications | |
| US8005206B1 (en) | VDSL splitter | |
| Vityazev et al. | A subband equalizer with the flexible structure of the analysis/synthesis subsystem | |
| CN113169921A (en) | Isolation circuit and device for controller area network communication | |
| CN110729978A (en) | High-frequency common mode rejection circuit and electrical apparatus | |
| CN102082886B (en) | Circuit and equipment of digital subscriber line | |
| JP2002539648A (en) | Low pass filter for ASDL diplexer | |
| US7298838B2 (en) | Adaptive cancellation network system and method for digital subscriber line | |
| WO2010019249A2 (en) | Method and apparatus for reducing transmitter ac-coupling droop | |
| US20040037352A1 (en) | XDSL system with improved impedance circuitry | |
| CN110676543B (en) | External loading type low-pass and band-stop microwave transmission line filter of coupling line with reconfigurable transmission response | |
| US4275368A (en) | EMC-/EMI-filter module | |
| EP2061158A1 (en) | Hybrid circuit without inductors | |
| CN207022188U (en) | A kind of multi-channel echo eliminates circuit and smart machine | |
| CN205490535U (en) | Can reduce network processing apparatus of inductance error | |
| GB2362063A (en) | Connecting broadband voice and data signals to telephone systems | |
| CN112865837B (en) | Communication apparatus and communication system | |
| CN212258956U (en) | Isolation circuit applied to power line carrier test system | |
| CN215529323U (en) | Integrated short wave frequency band frequency selection device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C12 | Rejection of a patent application after its publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20090812 |