CN101873155A - Method and device for estimating length of transmission line - Google Patents
Method and device for estimating length of transmission line Download PDFInfo
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- CN101873155A CN101873155A CN200910134755A CN200910134755A CN101873155A CN 101873155 A CN101873155 A CN 101873155A CN 200910134755 A CN200910134755 A CN 200910134755A CN 200910134755 A CN200910134755 A CN 200910134755A CN 101873155 A CN101873155 A CN 101873155A
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Abstract
The invention relates to a method for estimating the length of a transmission line, which comprises the steps of: generating a detecting signal to the transmission line, wherein the detecting signal sequentially comprises a first pulse and a second pulse which have reverse voltages; receiving a reflecting signal of the detecting signal from the transmission line; and judging the length of the transmission line according to a superposed waveform of the detecting signal and the reflecting signal. The name of the invention is method and device for estimating the length of the transmission line.
Description
Technical field
The present invention is about a kind of method and relevant apparatus thereof of estimating length of transmission line, especially about a kind of method and relevant apparatus thereof that is used for the length of Ethernet estimation transmission line.
Background technology
Ethernet (Ethernet) is a kind of network hardware standard of the IEEE of following 802.3 agreements, uses in Local Area Network widely at present.According to different demands, Ethernet device can connect by multiple different network media, for example twisted-pair feeder (twist pair), coaxial cable (coaxial cable) and optical fiber etc. are to support per second ten million bit mode (10Mbps), per second 100,000,000 bit modes (100Mbps) and per second 1,000,000,000 bit modes bit-rate mode such as (1Gbps).
Present most Ethernet device normally connects by twisted-pair feeder, and supports 10Mbps and two kinds of bit-rate mode of 100Mbps.At the beginning of network connectivity, two interconnected Ethernet device can be confirmed both sides' line ability and transmission rate by link pulse (link pulse) signal.For example, suppose that both sides and network media can both support the bit-rate mode of 100Mbps, then carry out line, otherwise the bit rate adjustment is become the 10Mbps of low speed with 100Mbps.
On the other hand, in order to save the power consumption of network system, known techniques generally can be utilized the Time Domain Reflectometry technology, and (Time Domain Reflectometry TDR) detects the length of transmission line of Ethernet, and the electric power with as data transmission the time is supplied with reference.The Time Domain Reflectometry technology is that the pulse signal that utilizes the impedance variation of transmission-wire terminal can cause importing produces the operation principle of reflection haply, come propagation time (travel-time) and velocity of wave, calculate the length of transmission line or the position that decision transmission line defective takes place according to reflected signal.
Yet, have as this area and to know usually known to the knowledgeable, if the length of transmission line is too short, also promptly when the distance of transmission-wire terminal and transmitting terminal is too near, because the propagation time of reflected signal also shortens significantly, therefore the situation that causes reflected signal to overlap together with the incident pulse signal and take place to differentiate can cause the existence of blind spot (blind spot) on detecting.In this case, known techniques generally can shorten the signal length of incident pulse signal, to improve the analytic ability of reflected signal.
Owing to also reduced the energy of incident pulse signal when the signal length of incident pulse signal is shortened, therefore, when the distance of transmission-wire terminal and transmitting terminal far the time, known techniques can can't detect reflected signal because of energy attenuation on the contrary.In addition, the pulse signal that shortens length also can't meet the standard of ethernet standard, and need expend extra hardware and produce.
Summary of the invention
Therefore, the present invention mainly is to provide a kind of method and device that is used for estimating the length of transmission line.
The present invention discloses a kind of method that is used for estimating the length of transmission line.This method includes the generation detection signal to this transmission line, and this detection signal includes first pulse and second pulse of voltage reversal in regular turn; Receive the reflected signal of this detection signal from this transmission line; And, judge the length of this transmission line according to the superposed waveform of this detection signal and this reflected signal.
The present invention also discloses a kind of estimating apparatus that is used for estimating the length of transmission line.This estimating apparatus includes signal generation unit, switch unit and estimation unit.This signal generation unit is used for producing detection signal to this transmission line.This detection signal includes first pulse and second pulse of voltage reversal in regular turn.This switch unit is coupled to this signal generation unit, is used for receiving from this transmission line the reflected signal of this detection signal.This estimation unit is coupled to this switch unit, is used for superposed waveform according to this detection signal and this reflected signal, judges the length of this transmission line.
Description of drawings
Fig. 1 is the schematic diagram of embodiment of the invention flow process.
Fig. 2 is the schematic diagram of legacy link pulse signal.
Fig. 3 is the schematic diagram of embodiment of the invention detection signal.
Fig. 4 is the schematic diagram of the superposed waveform of detection signal of the present invention and its reflected signal.
Fig. 5 is the schematic diagram of another superposed waveform of detection signal of the present invention and its reflected signal.
Fig. 6 is the schematic diagram of embodiment of the invention estimating apparatus.
The main element symbol description:
10 flow processs
100～140 steps
20 legacy link pulse signals
30 detection signals
31,41 positive voltage pulses
32 negative voltage pulses
40,50 superposed waveform
THR1, THR2 threshold value
60 estimating apparatus
61 signal generation units
62 switch units
63 estimation unit
632 first detecting units
634 second detecting units
636 judging units
Embodiment
Please refer to Fig. 1, Fig. 1 is the schematic diagram of embodiment of the invention flow process 10.Flow process 10 is used for the length of Ethernet estimation transmission line, and it includes the following step:
Step 100: beginning.
Step 110: produce detection signal to this transmission line, this detection signal includes first pulse and second pulse of voltage reversal in regular turn.
Step 120: the reflected signal that receives this detection signal from this transmission line.
Step 130:, judge the length of this transmission line according to the superposed waveform of this detection signal and this reflected signal.
Step 140: finish.
According to flow process 10, the embodiment of the invention produces has the detection signal of first pulse and second pulse to transmission line.Wherein, first pulse and second pulse have reverse voltage.Then, the embodiment of the invention with the superposed waveform according to detection signal and reflected signal, is judged the length of transmission line from the reflected signal of transmission line reception detection signal.
Preferably, first pulse and second pulse are positive voltage pulse and negative voltage pulse in regular turn, and the signal length of second pulse is less than the signal length of first pulse.In addition, above-mentioned detection signal meets link pulse (Link Pulse) waveform template of Ethernet.In this case, the voltage amplitude of second pulse levels off to the minimum voltage of link impulse waveform template.
Therefore, utilize to produce above-mentioned detection signal to transmission line, the embodiment of the invention can be come the length of sense transmission line according to the superposed waveform of detection signal and reflected signal, thereby solves the problem that blind spot exists in the known techniques.In addition, because detection signal meets the link impulse waveform template of Ethernet, so the embodiment of the invention need not use extra hardware to produce detection signal, and can save hardware spending.About the detail operations of flow process 10 of the present invention, please continue with reference to following explanation.
Please refer to Fig. 2 and Fig. 3, Fig. 2 is the schematic diagram of legacy link pulse signal 20, and Fig. 3 is the schematic diagram of embodiment of the invention detection signal 30.In Fig. 2 and Fig. 3, dotted line represents to meet the link impulse waveform template of ethernet standard, and solid line is then represented legacy link pulse signal 20 and detection signal 30 respectively.The definition of link impulse waveform template can not added to give unnecessary details in this with reference to the related protocol standard of IEEE 802.3.It should be noted that the negative voltage pulse in the legacy link pulse signal 20 is an overshoot (overshoot) pulse wave, but not the signal that painstakingly produces.In comparison, detection signal 30 includes positive voltage pulse 31 and negative voltage pulse 32 in regular turn.Wherein, the signal length of negative voltage pulse 32 can provide one to four sampling point of frequency of operation of Ethernet, also promptly be about ten to 20 nanoseconds (nanosecond, ns); And the voltage amplitude of negative voltage pulse 32 is about one to two. 5 volt.In this case, the embodiment of the invention can be judged the length of transmission line according to the superposed waveform of detection signal 30 with its reflected signal, to solve the problem that blind spot exists in the known techniques.
For instance, please refer to Fig. 4, Fig. 4 is the schematic diagram of the superposed waveform 40 of detection signal 30 of the present invention and its reflected signal.When the length of transmission line during less than first particular value, because the meeting of the reflected signal of positive voltage pulse 31 is complete and detection signal 30 overlaps, therefore, if detecting superposed waveform 40 has another positive voltage pulse 41 and (also is, the reflected signal of negative voltage pulse 32) and then appears at after the detection signal 30, then the embodiment of the invention can judge that the length of transmission line is less than first particular value, as shown in Figure 4.Certainly, the embodiment of the invention can during greater than threshold T HR1, just produce judged result at the voltage amplitude of positive voltage pulse 41, judges by accident because of detecting noise avoiding.
On the other hand, please refer to Fig. 5, Fig. 5 is the schematic diagram of another superposed waveform 50 of detection signal 30 of the present invention and its reflected signal.When the length of transmission line greater than first particular value during less than second particular value, because the reflected signal of positive voltage pulse 31 only can overlap with negative voltage pulse 32, therefore, if detecting the signal length of negative voltage pulse 32 in superposed waveform 50 increases, for example greater than threshold T HR2, then the embodiment of the invention can judge that the length of transmission line is between first particular value and second particular value, as shown in Figure 5.
For different transmission line characteristics, the scope of above-mentioned first particular value and second particular value is also inequality.(twist pair) is example with twisted-pair feeder, and above-mentioned first particular value is about eight meters, and second particular value is about 16 meters.Thus, the embodiment of the invention can be judged the length of transmission line according to the superposed waveform of detection signal 30 with its reflected signal, to solve the problem that blind spot exists in the known techniques.
In addition, when the length of transmission line during greater than second particular value, the embodiment of the invention also can be judged the length of transmission line according to the propagation time (travel time) of reflected signal, it is that this area has and knows that usually the knowledgeable of the knowledgeable institute knows, and does not add to give unnecessary details at this.
Please continue with reference to figure 6, Fig. 6 is the schematic diagram of embodiment of the invention estimating apparatus 60.Estimating apparatus 60 is to be used for realizing above-mentioned flow process 10, with the length of estimation transmission line in Ethernet.Estimating apparatus 60 includes signal generation unit 61, switch unit 62 and estimation unit 63.Signal generation unit 61 be used for producing above-mentioned meet link template pulse detection signal 30 to transmission line.Switch unit 62 is coupled to signal generation unit 62, is used for from the reflected signal of transmission line reception detection signal 30.63 of unit of estimation are coupled to switch unit 62, are used for judging the length of transmission line according to the superposed waveform of detection signal 30 with its reflected signal.
Preferably, judging unit 63 also includes first detecting unit 632, second detecting unit 634 and judging unit 636.Whether first detecting unit 632 is used for detecting superposed waveform has positive voltage pulse and is right after after detection signal 30; Whether the signal length that second detecting unit 634 is used for detecting negative voltage pulse 32 in the superposed waveform increases; Judging unit 636 then is used for according to the testing result of first detecting unit 632 and second detecting unit 634, judges the length of transmission line.
Thus, embodiment of the invention estimating apparatus 60 can be judged the length of transmission line according to the superposed waveform of detection signal 30 with its reflected signal, to solve the problem that blind spot exists in the known techniques.About the detail operations of embodiment of the invention estimating apparatus 60, please refer to the explanation of above-mentioned flow process 10, do not give unnecessary details at this.
Certainly, above-mentioned detection signal 30 also can be used as the usefulness of link pulse signal except being used for judging the length of transmission line, in order to confirm the line ability of network equipment at the beginning of network connectivity.It should be noted that in embodiments of the present invention the length of transmission line can be the length of transmission line that connects two network equipments, also can be any impedance place that do not match in the transmission line, and for example broken string place or fault location are to the distance of signal sending end.Corresponding variation like this also belongs to scope of the present invention.
In sum, embodiment of the invention utilization produces the detection signal of tool specific waveforms to transmission line, and can come the length of sense transmission line according to the superposed waveform of detection signal and reflected signal, thereby solves the problem that blind spot exists in the known techniques.In addition, because detection signal meets the link impulse waveform template of Ethernet, so the embodiment of the invention need not use extra hardware to produce detection signal, and can save hardware spending.
The above only is preferred embodiment of the present invention, and all equalizations of being done according to the present patent application claim change and modify, and all should belong to covering scope of the present invention.
Claims (21)
1. method that is used for estimating the length of transmission line, this method includes:
Produce detection signal to this transmission line, this detection signal includes first pulse and second pulse of voltage reversal in regular turn;
Receive the reflected signal of this detection signal from this transmission line; And
According to the superposed waveform of this detection signal and this reflected signal, judge the length of this transmission line.
2. the method for claim 1, wherein this first pulse is a positive voltage pulse, this second pulse is a negative voltage pulse.
3. method as claimed in claim 2, wherein the signal length of this second pulse is less than the signal length of this first pulse.
4. the method for claim 1, wherein this detection signal meets the link impulse waveform template of this Ethernet.
5. method as claimed in claim 4, wherein the voltage amplitude of this second pulse levels off to the minimum voltage of this link impulse waveform template.
6. the method for claim 1 wherein according to this superposed waveform of this detection signal and this reflected signal, is judged the step of the length of this transmission line, includes:
Have the 3rd pulse when being right after after this detection signal in this superposed waveform, the length of judging this transmission line is less than first particular value, and the 3rd pulse is the reflected signal of this second pulse.
7. method as claimed in claim 6, wherein the voltage amplitude of the 3rd pulse is greater than threshold value.
8. the method for claim 1 wherein according to this superposed waveform of this detection signal and this reflected signal, is judged the step of the length of this transmission line, includes:
When the signal length of this second pulse increased in this superposed waveform, the length of judging this transmission line was between first particular value and second particular value, and wherein this first particular value is less than this second particular value.
9. the method for claim 1, wherein the signal length of this second pulse provides the ethernet operation frequency one to four sampling point.
10. the method for claim 1, it also comprises:
According to the propagation time of this reflected signal, judge the length of this transmission line.
11. an estimating apparatus is used for estimating the length of transmission line, this estimating apparatus includes:
The signal generation unit is used for producing detection signal to this transmission line, and this detection signal includes first pulse and second pulse of voltage reversal in regular turn;
Switch unit is coupled to this signal generation unit, is used for receiving from this transmission line the reflected signal of this detection signal; And
The estimation unit is coupled to this switch unit, is used for superposed waveform according to this detection signal and this reflected signal, judges the length of this transmission line.
12. estimating apparatus as claimed in claim 11, wherein this first pulse is a positive voltage pulse, and this second pulse is a negative voltage pulse.
13. estimating apparatus as claimed in claim 12, wherein the signal length of this second pulse is less than the signal length of this first pulse.
14. estimating apparatus as claimed in claim 11, wherein this detection signal system meets the link impulse waveform template of this Ethernet.
15. estimating apparatus as claimed in claim 14, wherein the voltage amplitude of this second pulse levels off to the minimum voltage of this link impulse waveform template.
16. estimating apparatus as claimed in claim 11, wherein this estimation unit also includes:
First detecting unit is used for detecting this superposed waveform and whether has the 3rd pulse and be right after after this detection signal, and the 3rd pulse is the reflected signal of this second pulse;
Second detecting unit, whether the signal length that is used for detecting this second pulse in this superposed waveform increases; And
Judging unit is used for testing result according to this first detecting unit and this second detecting unit, judges the length of this transmission line.
17. estimating apparatus as claimed in claim 16, wherein this judging unit has the 3rd pulse when being right after after this detection signal in this superposed waveform, and the length of judging this transmission line is less than first particular value.
18. estimating apparatus as claimed in claim 17, wherein the voltage amplitude of the 3rd pulse is greater than threshold value.
19. estimating apparatus as claimed in claim 16, when wherein the signal length of this judging unit this second pulse in this superposed waveform increases, the length of judging this transmission line is between first particular value and second particular value, and wherein this first particular value is less than this second particular value.
20. estimating apparatus as claimed in claim 11, wherein the signal length of this second pulse can provide the ethernet operation frequency one to four sampling point.
21. estimating apparatus as claimed in claim 11, wherein this estimation unit also is used for the propagation time according to this reflected signal, judges the length of this transmission line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910134755A CN101873155A (en) | 2009-04-22 | 2009-04-22 | Method and device for estimating length of transmission line |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910134755A CN101873155A (en) | 2009-04-22 | 2009-04-22 | Method and device for estimating length of transmission line |
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| CN101873155A true CN101873155A (en) | 2010-10-27 |
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| CN200910134755A Pending CN101873155A (en) | 2009-04-22 | 2009-04-22 | Method and device for estimating length of transmission line |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013163875A1 (en) * | 2012-05-02 | 2013-11-07 | Qualcomm Incorporated | Cable length determination using variable-width pulses |
| CN112013506A (en) * | 2019-05-31 | 2020-12-01 | 青岛海尔空调电子有限公司 | Communication detection method and device and air conditioner |
-
2009
- 2009-04-22 CN CN200910134755A patent/CN101873155A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013163875A1 (en) * | 2012-05-02 | 2013-11-07 | Qualcomm Incorporated | Cable length determination using variable-width pulses |
| US9664496B2 (en) | 2012-05-02 | 2017-05-30 | Qualcomm Inc. | Cable length determination using variable-width pulses |
| CN112013506A (en) * | 2019-05-31 | 2020-12-01 | 青岛海尔空调电子有限公司 | Communication detection method and device and air conditioner |
| CN112013506B (en) * | 2019-05-31 | 2022-02-25 | 青岛海尔空调电子有限公司 | Communication detection method and device and air conditioner |
| US11611455B2 (en) | 2019-05-31 | 2023-03-21 | Qingdao Haier Air-Conditioning Electronic Co., Ltd. | Method and device for communication detection and air conditioner |
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Application publication date: 20101027 |