CN203180924U - Short-wave transceiving integrated system based on delay diversity - Google Patents
Short-wave transceiving integrated system based on delay diversity Download PDFInfo
- Publication number
- CN203180924U CN203180924U CN2012207243087U CN201220724308U CN203180924U CN 203180924 U CN203180924 U CN 203180924U CN 2012207243087 U CN2012207243087 U CN 2012207243087U CN 201220724308 U CN201220724308 U CN 201220724308U CN 203180924 U CN203180924 U CN 203180924U
- Authority
- CN
- China
- Prior art keywords
- short
- diversity
- signal
- chip
- module
- 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.)
- Expired - Fee Related
Links
Images
Landscapes
- Mobile Radio Communication Systems (AREA)
- Radio Transmission System (AREA)
Abstract
The utility model provides a short-wave transceiving integrated system based on delay diversity. The short-wave transceiving integrated system based on delay diversity includes a short-wave transceiving channel unit based on delay diversity, a six-channel filtering unit, a six-channel power amplifier, six antenna tuners and six short-wave antennas. When transmitting signals, the short-wave transceiving channel unit delays diversity and produces six channels of radio-frequency small signals. The six channels of the radio-frequency small signals are filtered by the six-channel filtering unit and amplified by the six-channel power amplifier. Six channels of 1kW short-wave radio-frequency signals are produced and are finally tuned by the short-wave tuners respectively and transmitted by the short-wave antennas. When receiving signals, the short-wave transceiving integrated system based on delay diversity can realize the receiving, demodulation and combination of six channels of the signals. The short-wave transceiving integrated system based on delay diversity provided by the utility model can realize functions of high-power transmitting and receiving of the six short-wave channels and the system integration degree is raised. By adopting the delay diversity technology according to the utility model, communication gain and anti-interference capacity can be improved.
Description
Technical field
The utility model relates to electronic circuit design field, and particularly designs a kind of based on the transceiving integrated system of shortwave that postpones diversity.
Background technology
In wireless communications environment, channel fading is the principal element that influences signal quality, and the decline of adopting the multi-antenna diversity method then can resist wireless channel effectively is for communication system provides reliable information transmission.The basic principle of multi-antenna diversity technology is the signal copy by a plurality of channel bearing identical information such as space, frequencies, and the energy of multiple signals merged transmitting and receiving diversity technique and all can obtain higher diversity gain in the multi-antenna diversity technology according to certain rule.Wherein the delay diversity technique in the transmit diversity comes down to manually to have made a kind of dispersive channel, a narrow band frequency non-selective fading channel is become frequency selective fading channels, thereby realized transmit diversity.This method advantage is to realize simply also being easy to combine with technology such as Space Time Coding, smart antennas, improves the reliability of physical layer information transmission.And in more existing Shortwave Communication System, often diversity technique and coding techniques are divided into different equipment, and can not realize integrated design, be difficult to the communication gain of maximum raising system.
The utility model content
It is a kind of based on the transceiving integrated system of shortwave that postpones diversity that the utility model purpose is to provide, and can realize the high-power function that transmits and receives of six shortwave passages, improved level of integrated system.This equipment postpones diversity technique by adopting, and can improve communication gain and antijamming capability.
For reaching above-mentioned purpose, the utility model proposes a kind of transceiving integrated system of shortwave based on the delay diversity, comprising: based on unit, short wave transmit-receive road, six channel filtering unit, No. six power amplifiers, six antenna tuners and six short-wave antennas of postponing diversity.When wherein sending signal, short wave transmit-receive road cell delay diversity produces six road RF small signals, respectively by six channel filtering unit filterings, amplify through No. six power amplifiers then, produce the short-wave radio frequency signal of six road 1kW, tuning by each short-wave antenna tuner respectively at last, launched by short-wave antenna; When receiving signal, this system can realize that the reception of six road signals, solution mediation merge: receive 6 short out ripple radiofrequency signals respectively by 6 short out wave antenna earlier, receive tuning by 6 antenna tuners respectively then, after switching is received and dispatched at the power amplifier place, deliver in the 6 channel filtering unit and carry out radiofrequency signal filtering, single channel merged after last 6 road signal unifications were delivered to and carried out 6 tunnel demodulation in the unit, short wave transmit-receive road, and channel-decoding becomes audio frequency and data.So because that a cover unit, short wave transmit-receive road supports to handle signal≤road that 6 tunnel radiofrequency signals handle at most is all passable.
Further, wherein unit, short wave transmit-receive road comprises: cpci bus and the main control module that is connected to cpci bus, interface module, the frequency synthesis module, radio-frequency module, digital signal processing module, front panel module and power module, wherein: main control module is suitable for carrying out the operation control to short wave transmit-receive road treatment facility, interface module is suitable for transmitting external audio frequency and data-signal, the frequency synthesis module is suitable for providing clock signal and the mixed frequency signal of each road signal, radio-frequency module is suitable for six short out ripple signals are carried out filtering and frequency conversion, and the signal after will handling transfers to digital signal processing module, digital signal processing module is to audio frequency or data-signal postpones or diversity is handled, when transmitting, allow the copy of same audio signal after the retardation of different length, launch from different antennas, during reception, data-signal is carried out diversity handle.
Further, wherein said digital signal processing module comprises 6 A/D chips, 2 down-conversion chips, 6 up-conversion modules, fpga chip, dsp chip and cpci bus, 6 A/D chips are connected to 2 down-conversion chips respectively, the output of 2 down-conversion chips is connected to fpga chip, it is mutual that dsp chip connects fpga chip, the cpci bus line data of going forward side by side respectively, the input of 6 up-conversion modules connects fpga chip
Further, wherein, when emission, dsp chip reads in voice data and external control order and voice data is encoded from cpci bus, postpone diversity and modulation, after the processing, 6 channel datas are through 6 A/D chips, export 6 short out ripple radiofrequency signals, when receiving, 6 A/D chips are sampled to 6 short out ripple intermediate-freuqncy signals, give two down-conversion chips respectively with the digital signal of sampling, do Digital Down Convert and handle, give fpga chip then and do the baseband filtering processing, fpga chip is realized the internal logic control of module simultaneously, digital signal after by FPGA filtering being handled is at last given dsp chip, by dsp chip digital signal is realized the diversity processing, the demodulation sign indicating number, and final output output digital baseband signal is to cpci bus.
Further, wherein also comprise memory, connect fpga chip, be used for the program of storage fpga chip.
Further, when dsp chip postpones diversity and handles described voice data, select signal retardation of information bit cycle, and dsp chip when being realized that diversity is handled, digital signal uses equalizer or Viterbi decoding to obtain diversity gain.
Further, according to claim 3 based on the transceiving integrated system of shortwave that postpones diversity, it is characterized in that, wherein the A/D chip is selected the AD9957 chip for use, the down-conversion chip is selected the HSP50216 chip for use, the up-conversion chip is selected the AD9957 chip for use, and dsp chip is selected the TMS320C6455 chip for use, and FPGA adopts Cyclone II FPGA.
The utility model is put forward the high-power function that transmits and receives that can realize six shortwave passages, has improved level of integrated system.This equipment postpones diversity technique by adopting, and can improve communication gain and antijamming capability.
Description of drawings
Fig. 1 is the theory diagram based on the transceiving integrated system of shortwave that postpones diversity of the utility model embodiment.
Fig. 2 is the theory diagram of Fig. 1 intermediate waves transceiver channel unit.
Fig. 3 is the theory diagram of digital signal processing module among Fig. 2.
Fig. 4 is that the signal when digital signal processing module is launched among Fig. 3 is handled schematic diagram.
Fig. 5 is that the signal when digital signal processing module receives among Fig. 3 is handled schematic diagram.
Embodiment
In order more to understand technology contents of the present utility model, especially exemplified by specific embodiment and cooperate appended graphic being described as follows.
Based on the composition schematic diagram of the transceiving integrated system of shortwave that postpones diversity as shown in Figure 1, this system is by forming based on unit, short wave transmit-receive road, six channel filtering unit, No. six power amplifiers, six antenna tuners and six short-wave antennas of postponing diversity.When wherein sending signal, short wave transmit-receive road cell delay diversity produces six road RF small signals, respectively by six channel filtering unit filterings, amplify through No. six power amplifiers then, produce the short-wave radio frequency signal of six road 1kW, tuning by each short-wave antenna tuner respectively at last, launched by short-wave antenna; When receiving signal, this system can realize that the reception of six road signals, solution mediation merge.
Wherein the filter function of six short out ripple radiofrequency signals can be realized in six channel filtering unit.In this unit, owing to switch the key that the switch of wave band inductance and tuning electric capacity is the restriction tuned speed, so the serial/parallel composite construction electronic switch that adopts PIN diode to constitute has high switching speed, and has the overpowering characteristics of high-isolation, low insertion loss and high pass.Simultaneously for the insertion loss of the compensation filter unit influence to transmitting power, after filtering by increase superlinearity, low noise amplifier compensates, and has reduced additional noise that amplifier brings into to the influence of system.
Fig. 2 is the theory diagram of Fig. 1 intermediate waves transceiver channel unit.Unit, short wave transmit-receive road comprises cpci bus and is connected to the main control module of cpci bus, interface module, the frequency synthesis module, radio-frequency module, digital signal processing module, front panel module and power module, wherein: main control module is suitable for carrying out the operation control to short wave transmit-receive road treatment facility, interface module is suitable for transmitting external audio frequency and data-signal, the frequency synthesis module is suitable for providing clock signal and the mixed frequency signal of each road signal, radio-frequency module is suitable for the multichannel short-wave signal is carried out filtering and frequency conversion, and the signal after will handling transfers to digital signal processing module, digital signal processing module postpones the diversity processing to audio frequency or data-signal, allow the delay of copy of same signal launch from different antennas, use equalizer or viterbi decoder to obtain diversity gain at receiving terminal.
Cpci bus is a kind of high performance industrial computer bus standard, and the CPCI module of a plurality of standards can be installed, and realizes carrying out transfer of data and information exchange; Have extreme high reliability, impact resistance, high density and vibration resistance, can support more slot, not only data transmission bauds is fast but also the slot standard, thereby digital signal is difficult for the disturbed requirement that can reduce total beta radiation.
The front panel module is suitable for providing close friend's man-machine interface, realizes operation and the human-computer interaction that shows.Interface module is suitable for transmitting external audio frequency and data-signal.Main control module is suitable for carrying out the operation control to short wave transmit-receive road treatment facility, comprises signal transmission and processing controls, shows the external output control of control, Digital Signal Processing control, audio frequency and data-signal etc.In the present embodiment, main control module can load WindowsXP or vxworks operating system, and the CPU in the main control module is the X86 of 1.0GHz, in save as 512M, and have two 10/100M self adaptation Ethernet interfaces, six serial ports, four road USB2.0, its pci bus meets the CPCI2.0R2.1 standard.Main control module carries out data communication and control interface module, frequency synthesis module, radio-frequency module and digital signal processing module by cpci bus and each module, can monitor the state of each module simultaneously.
The frequency synthesis module provides clock signal and the mixed frequency signal of each road signal.
In the present embodiment, each radio-frequency module is suitable for 2 short out ripple signals are carried out filtering and frequency conversion, produces intermediate-freuqncy signal, again the intermediate-freuqncy signal of each signalling channel is transferred to digital signal processing module and handles.Simultaneously, during as if the conduct excitation, can carry out the amplification of 20dB to 2 tunnel radiofrequency signals.
Fig. 3 is the theory diagram of integrated digital signal processing module among Fig. 2, as shown in Figure 3, based on the shortwave transmitting-receiving integrated digital signal processing module that postpones diversity, comprise: 6 A/D chips, 2 down-conversion chips, 6 up-conversion modules, fpga chip, dsp chip and cpci bus, 6 A/D chips are connected to 2 down-conversion chips respectively, the output of 2 down-conversion chips is connected to fpga chip, it is mutual that dsp chip connects fpga chip, the cpci bus line data of going forward side by side respectively, and the input of 6 up-conversion modules connects fpga chip.
Wherein adopt TMS320C6455 as dsp chip, this chip fast operation, memory source enrich, have the encoding and decoding coprocessor, have the master/slave pattern interface of 32bit/33MHz PCI simultaneously.Adopt the Cyclone II FPGA of altera corp, fast operation, and support the high-speed-differential data, select EPCS16 chip-stored FPGA program for use.A/D selects 6 AD9244 for use, selects 2 down-conversion chip HSP50216 for use, 6 up-conversion modules A D9957.
Dsp chip reads in voice data and external control order by cpci bus, and dsp chip returns state information to cpci bus again simultaneously.Signal when Fig. 4 launches for Fig. 3 intermediate waves transmitting-receiving integrated digital signal processing module is handled schematic diagram.With reference to figure 3 and Fig. 4, during emission, diversity and modulation are encoded, postponed to the voice data of DSP, and six channel datas after the processing are exported 6 short out ripple RF small signals through 6 AD9957 chips.
When receiving, with reference to figure 3 and Fig. 5,6 AD9244 sample to 6 short out ripple signals, give two HSP50216 chips (can handle 4 channel signals at most for every) respectively with the digital signal of sampling and do the Digital Down Convert processing, give fpga chip then and do the filtering processing, fpga chip is realized the internal logic control of module simultaneously, and the digital signal after by FPGA filtering being handled is at last given dsp chip, realizes that by dsp chip diversity is handled, the demodulation sign indicating number.Wherein the FPGA procedure stores is in the EPCS16 chip, and the DSP program is by the cpci bus load operating.The FPGA program generates by Quartus II compiling, and the DSP program generates by the compiling of CCS instrument.
In postponing the diversity handling process, 1 way word audio signal is postponed diversity handle.The signal of information source output at first carries out chnnel coding, becomes 6 tunnel identical information sequences through string and conversion then, finally by launching from 6 shortwave excitation passages after the delay of crossing different length.Should make the selection of retardation and respectively to encourage on the passage signal uncorrelated, long delay can increase the complexity of receiving terminal equilibrium, therefore selects signal retardation of information bit cycle usually.Use equalizer or Viterbi decoding to obtain diversity gain during reception.
In the utility model based on the transceiving integrated system of shortwave that postpones diversity, can realize the high-power function that transmits and receives of six shortwave passages.This equipment postpones diversity technique by adopting, and can improve communication gain and antijamming capability.System is made up of the higher unit of a plurality of integrated levels, significantly conserve space and weight.In wireless communications environment, channel fading is the principal element that influences signal quality, and the decline of adopting the multi-antenna diversity method then can resist wireless channel effectively is for communication system provides reliable information transmission.The basic principle of multi-antenna diversity technology is the signal copy by a plurality of channel bearing identical information such as space, frequencies, and the energy of multiple signals merged transmitting and receiving diversity technique and all can obtain higher diversity gain in the multi-antenna diversity technology according to certain rule.Wherein the delay diversity technique in the transmit diversity comes down to manually to have made a kind of dispersive channel, a narrow band frequency non-selective fading channel is become frequency selective fading channels, thereby realized transmit diversity.This method advantage is to realize simply also being easy to combine with technology such as Space Time Coding, smart antennas, improves the reliability of physical layer information transmission.And in more existing Shortwave Communication System, often diversity technique and coding techniques are divided into different equipment, and can not realize integrated design, be difficult to the communication gain of maximum raising system, by contrast, native system can greatly improve integrated level.
This utility model can be applied in the short wave communication, improves the gain of level of integrated system and signal of communication.
Though the utility model discloses as above with preferred embodiment, so it is not in order to limit the utility model.Have in the technical field under the utility model and know the knowledgeable usually, in not breaking away from spirit and scope of the present utility model, when being used for a variety of modifications and variations.Therefore, protection range of the present utility model is as the criterion when looking claims person of defining.
Claims (6)
1. the transceiving integrated system of shortwave based on the delay diversity is characterized in that, comprising:
Based on unit, short wave transmit-receive road, six channel filtering unit, No. six power amplifiers, six antenna tuners and six short-wave antennas of postponing diversity,
When wherein sending signal, short wave transmit-receive road cell delay diversity produces six road RF small signals, respectively by six channel filtering unit filterings, amplify through No. six power amplifiers then, produce the short-wave radio frequency signal of six road 1kW, tuning by each short-wave antenna tuner respectively at last, launched by short-wave antenna; When receiving signal, this system can realize that the reception of six road signals, solution mediation merge: receive 6 short out ripple radiofrequency signals respectively by 6 short out wave antenna earlier, receive tuning by 6 antenna tuners respectively then, after switching is received and dispatched at the power amplifier place, deliver in the 6 channel filtering unit and carry out radiofrequency signal filtering, single channel merged after last 6 road signal unifications were delivered to and carried out 6 tunnel demodulation in the unit, short wave transmit-receive road, and channel-decoding becomes audio frequency and data.
2. according to claim 1 based on the transceiving integrated system of shortwave that postpones diversity, it is characterized in that, wherein unit, short wave transmit-receive road comprises: cpci bus and the main control module that is connected to cpci bus, interface module, the frequency synthesis module, radio-frequency module, digital signal processing module, front panel module and power module, wherein: main control module is suitable for carrying out the operation control to short wave transmit-receive road treatment facility, interface module is suitable for transmitting external audio frequency and data-signal, the frequency synthesis module is suitable for providing clock signal and the mixed frequency signal of each road signal, radio-frequency module is suitable for six short out ripple signals are carried out filtering and frequency conversion, and the signal after will handling transfers to digital signal processing module, digital signal processing module is to audio frequency or data-signal postpones or diversity is handled, when transmitting, allow the copy of same audio signal after the retardation of different length, launch from different antennas, during reception, data-signal is carried out diversity handle.
3. according to claim 2 based on the transceiving integrated system of shortwave that postpones diversity, it is characterized in that, wherein said digital signal processing module comprises 6 A/D chips, 2 down-conversion chips, 6 up-conversion modules, fpga chip, dsp chip and cpci bus, 6 A/D chips are connected to 2 down-conversion chips respectively, the output of 2 down-conversion chips is connected to fpga chip, dsp chip connects fpga chip respectively, the cpci bus line data of going forward side by side is mutual, the input of 6 up-conversion modules connects fpga chip
Wherein, when emission, dsp chip reads in voice data and external control order and voice data is encoded from cpci bus, postpone diversity and modulation, after the processing, 6 channel datas are through 6 A/D chips, export 6 short out ripple radiofrequency signals, when receiving, 6 A/D chips are sampled to 6 short out ripple intermediate-freuqncy signals, give two down-conversion chips respectively with the digital signal of sampling, doing Digital Down Convert handles, give fpga chip then and do the baseband filtering processing, fpga chip is realized the internal logic control of module simultaneously, and the digital signal after by FPGA filtering being handled is at last given dsp chip, by dsp chip digital signal is realized the diversity processing, the demodulation sign indicating number, and finally export digital baseband signal to cpci bus.
4. the transceiving integrated system of shortwave based on the delay diversity according to claim 3 is characterized in that, it is characterized in that, wherein also comprises memory, connects fpga chip, is used for the program of storage fpga chip.
5. according to claim 3 based on the transceiving integrated system of shortwave that postpones diversity, it is characterized in that, when dsp chip postpones the diversity processing to described voice data, select signal retardation of information bit cycle, and dsp chip uses equalizer or Viterbi decoding to obtain diversity gain when digital signal is realized that diversity is handled.
6. according to claim 3 based on the transceiving integrated system of shortwave that postpones diversity, it is characterized in that, wherein the A/D chip is selected the AD9957 chip for use, the down-conversion chip is selected the HSP50216 chip for use, the up-conversion chip is selected the AD9957 chip for use, dsp chip is selected the TMS320C6455 chip for use, and FPGA adopts Cyclone II FPGA.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012207243087U CN203180924U (en) | 2012-12-25 | 2012-12-25 | Short-wave transceiving integrated system based on delay diversity |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012207243087U CN203180924U (en) | 2012-12-25 | 2012-12-25 | Short-wave transceiving integrated system based on delay diversity |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203180924U true CN203180924U (en) | 2013-09-04 |
Family
ID=49077578
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012207243087U Expired - Fee Related CN203180924U (en) | 2012-12-25 | 2012-12-25 | Short-wave transceiving integrated system based on delay diversity |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203180924U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103078671A (en) * | 2012-12-25 | 2013-05-01 | 熊猫电子集团有限公司 | Short-wave receiving-transmitting integration system based on delay diversity |
| CN109581080A (en) * | 2018-12-21 | 2019-04-05 | 武汉船舶通信研究所（中国船舶重工集团公司第七二二研究所） | For assessing the aerial test equipment of short-wave antenna performance |
| CN111742565A (en) * | 2018-02-20 | 2020-10-02 | 奥迪股份公司 | System for transmitting externally received signals within a motor vehicle |
-
2012
- 2012-12-25 CN CN2012207243087U patent/CN203180924U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103078671A (en) * | 2012-12-25 | 2013-05-01 | 熊猫电子集团有限公司 | Short-wave receiving-transmitting integration system based on delay diversity |
| CN103078671B (en) * | 2012-12-25 | 2015-04-22 | 熊猫电子集团有限公司 | Short-wave receiving-transmitting integration system based on delay diversity |
| CN111742565A (en) * | 2018-02-20 | 2020-10-02 | 奥迪股份公司 | System for transmitting externally received signals within a motor vehicle |
| CN111742565B (en) * | 2018-02-20 | 2024-03-29 | 奥迪股份公司 | System for transmitting externally received signals within a motor vehicle |
| CN109581080A (en) * | 2018-12-21 | 2019-04-05 | 武汉船舶通信研究所（中国船舶重工集团公司第七二二研究所） | For assessing the aerial test equipment of short-wave antenna performance |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103067059B (en) | Short wave receiving and sending communication channel process device based on delayed diversity and compact peripheral component interconnect (CPCI) bus | |
| CN103067058B (en) | Based on the shortwave transmitting-receiving integrated Digital Signal processing module of delay diversity | |
| CN109412657A (en) | Radio frequency system, antenna switching control method and Related product | |
| CN102404879B (en) | A kind of communication terminal | |
| CN206517409U (en) | A kind of wireless double-channel communication system | |
| CN103546189B (en) | Radio-frequency (RF) front-end circuit and system | |
| CN104506205A (en) | Radio frequency system of software-defined radio receiver | |
| CN114553250B (en) | Radio frequency system and communication device | |
| CN216490493U (en) | Satellite measurement and control satellite affair integrated system | |
| CN203180924U (en) | Short-wave transceiving integrated system based on delay diversity | |
| CN103078671B (en) | Short-wave receiving-transmitting integration system based on delay diversity | |
| CN111726138B (en) | Radio frequency circuit and electronic device | |
| CN105099481A (en) | Radio frequency transmit-receive method and system | |
| CN103679249A (en) | Radio-frequency chip interface circuit | |
| CN113708802B (en) | Module and method for promoting Bluetooth link budget and solving multipath effect | |
| CN203104446U (en) | Shortwave transmitting-receiving integrated digital signal processing module based on delay diversity | |
| CN203180923U (en) | Short-wave transceiving channel processing device based on relay diversity and CPCI bus | |
| CN103346813B (en) | Short-wave four-channel narrow-band diversity reception system | |
| CN102355199B (en) | Low-noise amplifier | |
| CN107294558A (en) | A kind of radio circuit transmitting-receiving structure and its design method | |
| CN205377877U (en) | Big data transmission system based on big dipper generation communication system | |
| CN204131515U (en) | A kind of mobile phone signal R-T unit | |
| CN213426495U (en) | Multi-band WCDMA small base station board | |
| CN219499554U (en) | WIFI-6 module and WIFI-6 router of external FEM | |
| CN111565063B (en) | Narrowband Internet of things system |
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 | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130904 Termination date: 20181225 |