CN201839287U - Remote transmission circuit for asynchronous serial data - Google Patents
Remote transmission circuit for asynchronous serial data Download PDFInfo
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- CN201839287U CN201839287U CN2010205649580U CN201020564958U CN201839287U CN 201839287 U CN201839287 U CN 201839287U CN 2010205649580 U CN2010205649580 U CN 2010205649580U CN 201020564958 U CN201020564958 U CN 201020564958U CN 201839287 U CN201839287 U CN 201839287U
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Abstract
The utility model relates to a remote transmission circuit for asynchronous serial data, comprising an asynchronous data level switch chip, a differential Manchester coder and decoder chip and a light signal transceiver, wherein the differential Manchester coder and decoder chip receives a local clock signal and is connected with the asynchronous data level switch chip and the light signal transceiver respectively in both way. The remote transmission circuit for asynchronous serial data has the characteristics that: (1) the transmission distance is long, the transmission rate is high and the anti-interference capability is strong; (2) as a CPLD (complex programmable logic device) chip is adopted, the differential Manchester coder and decoder chip shortens the development period of a system, and the portability and the expandability are good; (3) a CPLD element is relatively low in price, so that the cost is low; and (4) direct current component is unavailable, acute spectral characteristic is achieved, and more importantly, codes containing timing information are beneficial to timing extraction.
Description
Technical field
The utility model relates to the long-distance transmissions circuit of a kind of asynchronous serial data of utilizing this transmission medium realization of optical fiber.
Background technology
At present, the configuration of distributed automatization monitoring system bottom-layer network adopts the method for fieldbus to realize usually.Fieldbus is a kind of serial digital communication link between monitoring scene and the computer that is installed in monitoring chamber (center).And occasion that monitored point comparatively disperse abominable for monitoring of environmental generally uses the half-duplex form of RS-485 standard to realize, simple in structure with the fieldbus that the RS-485 form realizes, transmission range and load performance are all relatively good, so be extensive use of by people.But more than 1200 meters apart from the time, be subjected to the factor affecting (mainly being that transmission medium exists defective) of each side, the message transmission rate of serial asynchronous communication is set in 1200-9600bps usually.As use optical fiber bus performance is improved greatly as transmission medium, this is because Optical Fiber Transmission is compared with the cable transmission data acquisition system and had several advantages:
1. capacity is big, and the operating frequency of optical fiber is compared with cable and exceeded 8-9 the order of magnitude.
2. it is little to decay, hop distance (100-150Km).
3. fiber size is little, in light weight, is convenient to lay and transportation.
4. radiationless, optical fiber not disturbed by forceful electric power interference, electric railway and thunder and lightning disturbs, and the electromagnetic pulse-resisting ability is also very strong, good confidentiality.
5. non-ferrous metal is saved in abundant, the environmental protection of material source.Traditional telecommunication cable will consume a large amount of copper, aluminium etc., and the development of optical fiber communication will be saved a large amount of non-ferrous metals.
6. cost is low.Various in the market cable metal material prices rise steadily, and the optical fiber price is then more and more lower, and this has created important precondition for optical fiber communication obtains developing rapidly.
7. optical cable adaptability is strong, and the life-span is long.
Therefore Optical Fiber Transmission is applied in some surrounding environment more abominable telecommunication and data acquisition system more and more.
Summary of the invention
The purpose of this utility model is, overcomes the deficiency that prior art exists, and a kind of long-distance transmissions circuit of asynchronous serial data is provided.The asynchronous serial data long-distance transmissions that this circuit is realized by this transmission medium of optical fiber, its transmission range, transmission rate and antijamming capability are considerably beyond the existing asynchronous serial data communication that is undertaken by plain conductor.
The technical scheme that the utility model is taked for achieving the above object is: a kind of long-distance transmissions circuit of asynchronous serial data, it is characterized in that: comprise asynchronous data level transferring chip, Difference Manchester codec chip and optical signal transceiver device, described Difference Manchester codec chip receive the local clock signal and respectively with the asynchronous data level transferring chip, optical transceiver is two-way is connected.
Characteristics of the present utility model are: (1) optical fiber is as transmission medium, and its long transmission distance, transmission rate height and antijamming capability are strong.(2) adopt the CPLD chip to realize that the Difference Manchester codec chip shortens system development cycle, transplantability, favorable expandability.(3) digital codec part price is generally expensive in the fiber optic transmission system, and CPLD device price is relatively cheap, low cost.(4) Differential Manchester Encoding helps the high-speed transfer of optical fiber, and it does not contain DC component, and more sharp-pointed spectral characteristic is arranged, and importantly contains timing information in the sign indicating number type, helps Clock Extraction.
Description of drawings
Fig. 1 is that circuit of the present utility model connects block diagram.
Fig. 2 is the utility model RS232 interface and data level conversion chip circuit diagram.
Fig. 3 is a Difference Manchester codec chip internal circuit configuration block diagram.
Fig. 4 is the utility model optical transceiver circuit diagram.
Fig. 5 is several binary code type comparison diagrams commonly used.
Embodiment
As shown in Figure 1, a kind of long-distance transmissions circuit of asynchronous serial data comprises asynchronous data level transferring chip, Difference Manchester codec chip and optical signal transceiver device.The Difference Manchester codec chip receive the local clock signal and respectively with the asynchronous data level transferring chip, optical transceiver is two-way is connected.
The optical signal transceiver device comes down to an electrooptic modulator among the figure, the signal of telecommunication that it sends with the Differential Manchester Encoding device is modulated light source and is become light signal, modulatedly be transferred to receiving terminal after coupling light in the optical fiber, the optoelectronic detector spare of receiving terminal is demodulated to the signal of telecommunication to light signal, delivers to the NRZ signal of last output Transistor-Transistor Logic level in the Difference Manchester decoder after amplification, shaping are handled.
As shown in Figure 2,1 pin that the circuit of asynchronous data level transferring chip is connected to level transferring chip D1 is connected with 3 pin by capacitor C 1, and 2 pin connect power supply by capacitor C 3,4 pin connect 5 pin by capacitor C 2,6 pin pass through capacitor C 4 ground connection, 8 pin, 10 pin, 15 pin ground connection, and 16 pin connect power supply.
When equipment room transmission asynchronous serial data, adopt RS422 or RS232 level usually, should pass through level transferring chip so enter the asynchronous data of native system, after being become Transistor-Transistor Logic level, it carries out encoding process again.
As shown in Figure 5, not being both of Difference Manchester sign indicating number and Manchester code maximum, it changes the waveform of representing with absolute level in the Manchester code with the relative variation of level into represents that this is in order to solve the decoding error that the recipient causes because of polarity inversion.The waveform of unipolarity nonreturn to zero code (NRZ sign indicating number), mark differential code (NRZ (M)), Manchester code and Difference Manchester sign indicating number has drawn among Fig. 5.
As seen from Figure 5, Manchester code is by the mould two of timer clock and NRZ sign indicating number and produces, and the Difference Manchester sign indicating number is by the mould two of timer clock and NRZ (M) sign indicating number and produces, and can finish in two steps so the NRZ sign indicating number will be converted to Difference Manchester sign indicating number (cataloged procedure): 1. earlier the NRZ sign indicating number is converted to NRZ (M) sign indicating number (difference mark code); 2. again NRZ (M) sign indicating number that obtains is carried out the logic xor operation with timer clock, just obtained the Difference Manchester sign indicating number.In like manner decode procedure is the inverse process of coding, promptly earlier the Difference Manchester sign indicating number is converted to NRZ (M) sign indicating number, again NRZ (M) sign indicating number is converted to the NRZ sign indicating number.
Because the CPLD family chip has gate circuit integrated level height, can be configured to multiple input, for a long time clock drive, include RAM or Flash (part is supported in the wire system programming), can encryption, outstanding features such as low-voltage, low-power consumption and low cost, so be the splendid selection that realizes some specific function chips.Whole Difference Manchester codec chip is realized by a CPLD, adopts the Verilog-HDL language compilation, utilization of resources situation: less than 200 logical blocks and 11 I/O ports.There are two control signals in system shown in Figure 3: self check is controlled and is returned control (it is effective to be low level), and this has also determined the working method of three selectors and the mode of operation of system, describes respectively below.
The explanation of selector working method:
The selector I. when self check is controlled to be logic ' height ', the NRZ signal of the outside input of pio chip.
When self check is controlled to be logic ' low ', the self-test signal that pio chip built in self testing module is sent.
When the self check of selector II is controlled to be logic ' height ', the Difference Manchester sign indicating number of the outside input of pio chip.
When self check is controlled to be logic ' low ', the Difference Manchester sign indicating number behind the output nrz encoding.
The selector III. return when being controlled to be logic ' height ' signal that outlet selector 2 comes out.
Return when being controlled to be logic ' low ' signal that output Differential Manchester Encoding module is come out.
The operating state explanation of system:
1.. operate as normal self check control end is a high level, and returning control end is high level;
2.. self check state self check control end is a low level, and returning control end is high level;
3.. returning state self check control end is high level, and returning control end is low level.
System is under the normal operating conditions, and as shown in Figure 3, the NRZ sign indicating number of chip exterior input enters into the Differential Manchester Encoding module through selector 1, and this module converts the NRZ sign indicating number to the Difference Manchester sign indicating number through externally exporting with door 1; The Difference Manchester sign indicating number of chip exterior input simultaneously enters into the Difference Manchester decoder module through selector 2, selector 3, the at first extraction of completion bit synchronised clock in this module, utilize the bit synchronization clock that extracts that the Difference Manchester sign indicating number is converted to the NRZ sign indicating number again, the NRZ sign indicating number after the conversion is by externally exporting with door 2.So just finished the function that normal Difference Manchester sign indicating number commentaries on classics NRZ sign indicating number and the slip of NRZ sign indicating number divide Manchester code.
When system is in the self check operating state, as shown in Figure 3, chip neither response external input is not externally exported NRZ sign indicating number and Difference Manchester sign indicating number yet, at this moment selftest module sends the NRZ signal that has the anchor-frame structure, so this frame structure is simple as far as possible owing to just being used for self check, therefore designed a frame structure with 8 bit synchronization frame heads (8 bits are 10011011) and 120 bit data (all being logic low), the NRZ data of band frame head enter the Differential Manchester Encoding module through selector 1, the Difference Manchester sign indicating number that coding obtains is through selector 2, selector 3 enters into the Difference Manchester decoder module, selftest module is given in NRZ sign indicating number that decoding obtains and the bit synchronization clock loopback of extracting, selftest module then illustrates Difference Manchester codec chip (the self-detection result output is a high level) working properly synchronously if can extract the frame synchronization head and the achieve frame of previous transmission, otherwise explanation work undesired (the self-detection result output is a low level).
The state of returning is in order to be applied to some special test environments, at this moment the Difference Manchester codec chip is in a kind of closed loop state, the NRZ sign indicating number of outside input does not externally send after being converted to the Difference Manchester sign indicating number, but directly given decoder module again, the NRZ sign indicating number that decoding obtains is externally exported.
As shown in Figure 4, the circuit of optical signal transceiver device is connected to: resistance R 6, resistance R 8, resistance R 10, resistance R 12, resistance R 13, resistance R 11, resistance R 9, resistance R 7 series connection, the tie point ground connection of resistance R 6 and resistance R 7, the tie point one tunnel of resistance R 7 and resistance R 9 connects optical transceiver module 2 pin, another road is by resistance R 2 and capacitor C 6 ground connection, the tie point of resistance R 6 and resistance R 8 connects optical transceiver module 3 pin, the tie point of resistance R 8 and resistance R 10 and the tie point of resistance R 9 and resistance R 11 are connected and connect 5 pin and 6 pin of optical transceiver module, the tie point of resistance R 10 and resistance R 12 connects optical transceiver module 7 pin, the tie point one tunnel of resistance R 11 and resistance R 13 connects optical transceiver module 8 pin, another road is by resistance R 3 and capacitor C 7 ground connection, the tie point ground connection of resistance R 12 and resistance R 13,1 pin of optical transceiver module, 9 pin ground connection.
The signal of telecommunication behind the coding is modulated in optical signal transceiver device interior focusing source and is become light signal, passes through Optical Fiber Transmission.
Claims (4)
1. the long-distance transmissions circuit of an asynchronous serial data, it is characterized in that: comprise asynchronous data level transferring chip, Difference Manchester codec chip and optical signal transceiver device, described Difference Manchester codec chip receive the local clock signal and respectively with the asynchronous data level transferring chip, optical transceiver is two-way is connected.
2. the long-distance transmissions circuit of asynchronous serial data according to claim 1, it is characterized in that: described Difference Manchester codec chip internal circuit configuration is: the Differential Manchester Encoding module is respectively with the selector I, be connected with door an I, selector II, selector III, the Difference Manchester decoder module is connected respectively with door II, selftest module, selector III, the selector I respectively with selftest module, with a door II, be connected with I, selector II.
3. the long-distance transmissions circuit of asynchronous serial data according to claim 1, it is characterized in that: 1 pin that the circuit of described asynchronous data level transferring chip is connected to level transferring chip D1 is connected with 3 pin by capacitor C 1,2 pin connect power supply by capacitor C 3,4 pin connect 5 pin by capacitor C 2,6 pin are by capacitor C 4 ground connection, 8 pin, 10 pin, 15 pin ground connection, 16 pin connect power supply.
4. the long-distance transmissions circuit of asynchronous serial data according to claim 1, it is characterized in that: the circuit of described optical signal transceiver device is connected to: resistance R 6, resistance R 8, resistance R 10, resistance R 12, resistance R 13, resistance R 11, resistance R 9, resistance R 7 series connection, the tie point ground connection of resistance R 6 and resistance R 7, the tie point one tunnel of resistance R 7 and resistance R 9 connects optical transceiver module 2 pin, another road is by resistance R 2 and capacitor C 6 ground connection, the tie point of resistance R 6 and resistance R 8 connects 3 pin of optical transceiver module X2, the tie point of resistance R 8 and resistance R 10 and the tie point of resistance R 9 and resistance R 11 are connected and connect 5 pin and 6 pin of optical transceiver module X2, the tie point of resistance R 10 and resistance R 12 connects 7 pin of optical transceiver module X2, the tie point one tunnel of resistance R 11 and resistance R 13 connects 8 pin of optical transceiver module X2, another road is by resistance R 3 and capacitor C 7 ground connection, the tie point ground connection of resistance R 12 and resistance R 13,1 pin of the X2 of optical transceiver module, 9 pin ground connection.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2010205649580U CN201839287U (en) | 2010-10-18 | 2010-10-18 | Remote transmission circuit for asynchronous serial data |
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| CN2010205649580U CN201839287U (en) | 2010-10-18 | 2010-10-18 | Remote transmission circuit for asynchronous serial data |
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| CN201839287U true CN201839287U (en) | 2011-05-18 |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103516392A (en) * | 2013-06-21 | 2014-01-15 | 北京汉邦高科数字技术股份有限公司 | Transmission equipment and method for asynchronous serial data |
| CN104283664A (en) * | 2013-07-08 | 2015-01-14 | 美国亚德诺半导体公司 | Differential decoder |
| CN104978301A (en) * | 2014-04-09 | 2015-10-14 | Nxp股份有限公司 | Two-line differential bus receiving and sending system based on I2C bus protocol and I2C double-line differential communication method |
| CN106253986A (en) * | 2016-08-18 | 2016-12-21 | 桂林创研科技有限公司 | Fiber optic communications devices |
| CN106452580A (en) * | 2016-06-30 | 2017-02-22 | 华南理工大学 | Visible light communication coding method compatible with smartphone camera and system thereof |
| CN108400817A (en) * | 2018-03-19 | 2018-08-14 | 西安电子科技大学 | A kind of visible light communication method for transmitting Manchester's code based on serial ports |
| CN112702068A (en) * | 2020-12-25 | 2021-04-23 | 深圳市元征科技股份有限公司 | Coded data processing method, device, equipment and storage medium |
-
2010
- 2010-10-18 CN CN2010205649580U patent/CN201839287U/en not_active Expired - Fee Related
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103516392A (en) * | 2013-06-21 | 2014-01-15 | 北京汉邦高科数字技术股份有限公司 | Transmission equipment and method for asynchronous serial data |
| CN104283664A (en) * | 2013-07-08 | 2015-01-14 | 美国亚德诺半导体公司 | Differential decoder |
| CN104283664B (en) * | 2013-07-08 | 2017-12-08 | 美国亚德诺半导体公司 | differential decoder |
| CN104978301A (en) * | 2014-04-09 | 2015-10-14 | Nxp股份有限公司 | Two-line differential bus receiving and sending system based on I2C bus protocol and I2C double-line differential communication method |
| CN104978301B (en) * | 2014-04-09 | 2019-08-13 | Nxp股份有限公司 | Two-wire differential bus receive-transmit system and I2C two-wire differential communication method based on I2C bus protocol |
| CN106452580A (en) * | 2016-06-30 | 2017-02-22 | 华南理工大学 | Visible light communication coding method compatible with smartphone camera and system thereof |
| CN106253986A (en) * | 2016-08-18 | 2016-12-21 | 桂林创研科技有限公司 | Fiber optic communications devices |
| CN108400817A (en) * | 2018-03-19 | 2018-08-14 | 西安电子科技大学 | A kind of visible light communication method for transmitting Manchester's code based on serial ports |
| CN112702068A (en) * | 2020-12-25 | 2021-04-23 | 深圳市元征科技股份有限公司 | Coded data processing method, device, equipment and storage medium |
| CN112702068B (en) * | 2020-12-25 | 2024-04-02 | 深圳市元征科技股份有限公司 | Method, device, equipment and storage medium for processing coded data |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20110518 Termination date: 20131018 |