CN1705379A - Line length measuring device used for computer switching device and measuring method thereof - Google Patents
Line length measuring device used for computer switching device and measuring method thereof Download PDFInfo
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- CN1705379A CN1705379A CN 200410042772 CN200410042772A CN1705379A CN 1705379 A CN1705379 A CN 1705379A CN 200410042772 CN200410042772 CN 200410042772 CN 200410042772 A CN200410042772 A CN 200410042772A CN 1705379 A CN1705379 A CN 1705379A
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Abstract
This invention provides a line length measurer and method for measuring length of video signal transmission line, which contains at least signal synthesizing circuit for superposing an electronic signal to a pair of sub lines of transmission line, a signal conversion circuit for converting transmitted electronic signal into a value, and a line length calculation circuit for calculating length of transmission line, said invention has not any interference to user, improves band width and signal delay, compensates the analog signal attenuation due to transmission line length.
Description
Technical field
The present invention relates to a kind of Line length measurer, particularly relate to a kind of device that is used for measure analog signals transmission line line length.
Background technology
Because the fast development of information technology makes that the application of computer and peripheral product thereof is quite universal.The computer user utilizes input equipments such as mouse, keyboard that computer is operated usually, computer is presented at the state of computer on the monitor by output equipments such as monitor, loudspeaker or utilizes the sound indication, thereby makes the computer user can grasp the real-time status of computer at any time.
Display screen uses three kinds of chrominance signals usually, and is for example red, green, blue, handles change in color, and all colours all can be obtained by these three kinds of chrominance signal stacks.In addition,, utilize the mode of controlling voltage to adjust the color of image frame, each pixel can both be shown, with continuous color range to present bright-coloured image quality true to nature because general display screen is simulation output.
In personal computer, when vision signal utilized display card to export on the display screen by Network transmission line, vision signal can produce signal attenuation along with the impedance matching of Network transmission line.If do not carry out compensated video signal, the picture on the display screen will be smudgy; On the contrary, if, then too drastic phenomenon can occur, reduce the useful life of display screen to the overcompensate of vision signal.
Moreover when transmission line surpassed 10 meters, vision signal will significantly decay, and causes the picture quality of display screen not good, even can't distinguish the operation screen on the display screen.In addition, multi-form transmission line, protected type twisted-pair feeder (ShieldingTwisted Pair for example, STP) or tinfoil paper twisted-pair feeder (Foil Twisted Pair, FTP), its frequency response is also inequality, thereby when causing carrying out video signal transmission, and vision signal can produce in various degree signal attenuation or distortion because of different transmission lines.These reasons make and are difficult to use simple signal compensation apparatus to compensate the signal attenuation or the distortion of different length or the generation of different types of transmission line by fixed form in actual applications.
The time difference of prior art use high-speed data-flow emission and passback is estimated the length of transmission line, but the very high and difficult realization of this method cost.Also have a kind of method in addition, it with measuring electronic signal timesharing superposition to the sub-line of the UART in the transmission line.The sub-line of UART mainly is the electronic signal that is used for transmitting keyboard or mouse etc.Yet, the length of the communication ability energy measurement transmission line of other signals in the necessary first interruption U ART line of this method.For the busy occasion of some communications, for example continue to use the keyboard or the mouse of USB interface, this method can significantly reduce the bandwidth of signal and communication, and causes the delay of electronic signal.
Summary of the invention
In view of this, the object of the present invention is to provide a kind of Line length measurer, it is with low cost and circuit is simple, is applicable to cooperate signal compensation apparatus to compensate the signal of decaying because of line length.
Another object of the present invention is to provide a kind of Line length measurer, be disposed at computer switch, in order to the length of the transmission line of the different length that measure to connect computer switch or kind, and with its foundation as compensated video signal.
Another purpose of the present invention is to provide a kind of line length method of measurement, can not take the communication bandwidth of other signals when measuring the transmission line line length, and method is simple and be easy to be used in combination with other method for compensating signal.
For reaching above-mentioned purpose of the present invention, a kind of Line length measurer is proposed, for the length of the transmission line of measuring transmission video signal, wherein this transmission line has at least three antithetical phrase lines.This Line length measurer comprises at least: a signal synthesis circuit, a signaling conversion circuit and a line length counting circuit.When the vertical synchronizing signal in this vision signal was effective, signal synthesis circuit was with electronic signal superposition to an antithetical phrase line.Signaling conversion circuit will convert a numerical value to through this electronic signal after this sub-line transmission.The line length counting circuit goes out the line length of this transmission line according to this numerical computations.
For reaching another object of the present invention, a kind of line length method of measurement is proposed, for the length of the transmission line of measuring transmission video signal.When the vertical synchronizing signal in the vision signal is effective, with an electronic signal superposition to three chrominance signals of this vision signal, to convert a numerical value through this electronic signal after this transmission line to then, and go out the line length of this transmission line according to this numerical computations.
According to Line length measurer of the present invention, this device comprises a signal extracting circuit, from the chrominance signal of superposition vertical synchronizing signal, extract vertical synchronizing signal, and when the vertical synchronizing signal of extracting was effective, the line length counting circuit calculated the line length of this transmission line.
According to Line length measurer of the present invention, this device comprises a signaling conversion circuit.This signaling conversion circuit comprises: a filter circuit is filtered into direct current signal with single-wire signal; A DC level switching circuit is adjusted the DC level of this direct current signal; And an analog-to-digital conversion circuit, convert this direct current signal of adjusted DC level to numerical value.
According to line length method of measurement of the present invention, when the horizontal-drive signal in vertical synchronizing signal and vision signal when respectively superposition is in two chrominance signals, with the electronic signal superposition to remaining chrominance signal.
According to line length method of measurement of the present invention, this electronic signal is a standard square-wave signal, and the frequency range of this standard square-wave signal and is advisable with 8MHz between about 4MHz to 12MHz.
According to line length method of measurement of the present invention, the switch process of this electronic signal comprises: will be filtered into a direct current signal through this electronic signal after the transmission line, adjust the DC level of this direct current signal then, and convert this direct current signal of adjusted DC level to this numerical value.
According to line length method of measurement of the present invention, this set-up procedure comprises: provide the DC level of a normal voltage and this direct current signal to make comparisons; When the difference of the DC level of this direct current signal and this normal voltage is big, heighten the output voltage of this direct current signal; When the difference of the DC level of this direct current signal and this normal voltage hour, turn down the output voltage of this direct current signal.
According to line length method of measurement of the present invention, the superposition step of this electronic signal comprises: convert this electronic signal to a differential wave and transmit for transmission line; This differential wave after the transmission is reduced into a single-wire signal, for converting this numerical value to.
According to line length method of measurement of the present invention, this method extracts this vertical synchronizing signal from the chrominance signal of superposition vertical synchronizing signal, and when this vertical synchronizing signal of being extracted is effective, calculates the line length of this transmission line.
The electronic signal of superposition of the present invention can not cause any interference to the user, made full use of the idle bandwidth of script in the transmission line, improved known technology owing to taking problems such as reduction communication bandwidth that UART line causes and signal delay, employed electronic component structure is simple, with low cost and be easy to use, and cooperates the decay of the analog signal that compensation that signal compensation apparatus can be effective and correct causes owing to the line length of transmission line.
Description of drawings
Fig. 1 is the schematic diagram of a preferred embodiment of the present invention.
Fig. 2 is the concrete schematic diagram of preferred embodiment shown in Figure 1.
Fig. 3 is the 8MHz signal generator 214 shown in Figure 2 and the detailed maps of signal synthesis circuit 210.
Fig. 4 is the level shown in Figure 2 and the detailed maps of vertical synchronizing signal extraction circuit 232.
Fig. 5 is the 8MHz signal extracting circuit 234 shown in Figure 2 and the detailed maps of signaling conversion circuit 206.
Embodiment
Fig. 1 is the schematic diagram of a preferred embodiment of the present invention.Line length measurer 100 is used to measure the line length of the transmission line 104 of transmission video signal.Transmission line 104 has at least three antithetical phrase lines, these three antithetical phrases line, three chrominance signals that corresponding transmission video signal comprised respectively, for example red (R), green (G) and blueness (B), perhaps brightness (Y), colourity (U) and aberration (V).Usually, except three chrominance signals, vision signal also comprises a horizontal-drive signal (H) and a vertical synchronizing signal (V).
Above-mentioned three chrominance signals are analog signals, and horizontal-drive signal and vertical synchronizing signal are digital signals.Analog signal can produce signal attenuation when growing Distance Transmission, thereby causes the distortion and the distortion of signal itself, but digital signal this type of problem can not take place.
This Line length measurer 100 comprises signal synthesis circuit 102, signaling conversion circuit 106 and line length counting circuit 108 at least.Vision signal at first is input to signal synthesis circuit 102.When the vertical synchronizing signal of vision signal was effective, signal synthesis circuit 102 can be with electronic signal, standard square-wave signal for example, and superposition is to a certain chrominance signal.When vertical synchronizing signal was effective, display can not exported any vision signal.That is to say that when vertical synchronizing signal was effective, the electronic signal of this other superposition can not show any picture on display, therefore can not cause any interference the user.
Signaling conversion circuit 106 will convert a numerical value to through this electronic signal after transmission line 104 transmission, for example use analog-to-digital conversion circuit to finish conversion between analog signal and data.Then, line length counting circuit 108 can go out the line length of transmission line 104 according to this numerical computations, compensates the signal attenuation of the transmission line 104 of different length or kind for follow-up signal compensation apparatus.
Fig. 2 is the concrete schematic diagram of preferred embodiment shown in Figure 1.Image output device 212, for example the display card of computer can pass through transmission line 204 outputting video signals to display 242.This vision signal has red color signal (R), green tint signal (G), blue chrominance signal (B), horizontal-drive signal (H) and vertical synchronizing signal (V).Transmission line 204 has three antithetical phrase lines, is responsible for transmitting red color signal (R), green tint signal (G), blue chrominance signal (B) respectively.Horizontal-drive signal (H) and vertical synchronizing signal (V) respectively superposition in above-mentioned three chrominance signals on any two.
Although can be up to about 66MHz on the frequency theory of vision signal, the frequency range of most of vision signal be usually between about 4MHz to 12MHz.The frequency response of the degree of signal attenuation and transmission line 204 is relevant with the frequency of signal itself.Therefore, this preferred embodiment uses a 8MHz signal generator 214 to produce the standard square-wave signal of frequency for about 8MHz, uses for the line length of measuring transmission line 204.
When vertical synchronizing signal is effective, signal synthesis circuit 210 with this 8MHz standard square-wave signal superposition to another not in the chrominance signal of superposition level or vertical synchronizing signal.That is to say that three chrominance signals are distinguished superposition horizontal-drive signal, vertical synchronizing signal and 8MHz standard square-wave signal by transmission line the time.Yet this preferred embodiment does not limit different color signal and level, vertical synchronizing signal and the compound mode of standard square-wave signal when superposition, and any combination is all preferable applicable to this
Embodiment.
In addition, if run into the situation that vertical synchronizing signal in the vision signal and horizontal-drive signal merge, for example the vision signal of SUN system must be separated vertical synchronizing signal earlier with horizontal-drive signal, and then distinguishes superposition to chrominance signal.
Superposition the chrominance signal of other digital signals through transmission line 204 transmission after, received by signal receiving circuit 216, reverted to three chrominance signals that do not contain other digital signals by chrominance signal restore circuit 222 then.But after transmission line 204 transmission, signal attenuation or distortion more or less all can take place in the chrominance signal of these simulations, cause the picture distortion of display 242.
Level and vertical synchronizing signal extract circuit 232 respectively from superposition extract horizontal-drive signal and vertical synchronizing signal the chrominance signal of other digital signals.8MHz signal extracting circuit 234 from superposition the chrominance signal of other digital signals extract 8MHz standard square-wave signal.In this preferred embodiment, level and vertical synchronizing signal are extracted three signal extracting circuits that circuit 232 and 8MHz signal extracting circuit 234 are connected three antithetical phrase lines respectively, extract horizontal-drive signal, vertical synchronizing signal and standard square-wave signal respectively.
8MHz standard square-wave signal through after transmission line 204 transmission can be converted to data, for example a magnitude of voltage by signaling conversion circuit 206.Then, central processing unit 208 can be extrapolated the length of transmission line 204 according to the size of these data, and uses the chrominance signal of 224 above-mentioned generation signal attenuations of compensation of chrominance signal compensating circuit or distortion.Chrominance signal after horizontal-drive signal, vertical synchronizing signal and the quilt compensation exports display 242 to by image signal output end 240 again, to show correct, undistorted image frame.
Fig. 3 is the 8MHz signal generator 214 shown in Figure 2 and the detailed maps of signal synthesis circuit 210.Frequency elimination element 302 with 16MHz standard square-wave signal divided by two, and when vertical synchronizing signal is effective output 8MHz standard square-wave signal.Then, use differential circuit 304 superposition 8MHz standard square-wave signal and vertical synchronizing signals, and the conversion of signals behind the superposition is become a differential wave, transmit for transmission line.In this preferred embodiment, horizontal-drive signal, vertical synchronizing signal also are to utilize other differential circuit 304 to be superimposed on respectively on two other chrominance signal.Because the transmission rate of differential wave is very fast,, be the less signal transmission form of a kind of distortion therefore for the simulation chrominance signal.
Fig. 4 is the level shown in Figure 2 and the detailed maps of vertical synchronizing signal extraction circuit 232.Differential wave can be changed back common single-wire signal after growing Distance Transmission through transmission line 204.In this single-wire signal, chrominance signal is a positive signal, and the level of superposition or vertical synchronizing signal are negative signal.
Therefore, extract in the circuit 232 in level and vertical synchronizing signal, when the single-wire signal of input is timing, semiconductor 402 by and semiconductor 404 conductings, this moment, output signal was approximately zero, promptly signal is that positive chrominance signal can't externally be exported.When the single-wire signal of input when negative, semiconductor 402 conductings and semiconductor 404 ends, the signal of this moment output is being for just, and promptly this level and vertical synchronizing signal are extracted circuit 232 and utilized two semiconductors 402 and 404 with the taking-up of the negative signal in the single-wire signal, restore level or vertical synchronizing signal.
It should be noted that this preferred embodiment is from using two levels and vertical synchronizing signal extraction circuit 232 to extract horizontal-drive signal and vertical synchronizing signal respectively.Moreover level that extracts or vertical synchronizing signal are positive signals, and be just in time opposite with original negative signal, but this can not cause harmful effect to the signal processing of back.
Fig. 5 is the 8MHz signal extracting circuit 234 shown in Figure 2 and the detailed maps of signaling conversion circuit 206.Differential wave can be changed back common single-wire signal after growing Distance Transmission through transmission line 204.Single-wire signal after wave circuit 502 filtering, becomes direct current signal and exports DC level switching circuit 504 to after filtration.Defeated line 204 is long more, and this moment, the decay of direct current signal was big more, and its direct current is more little; Otherwise transmission line 204 is short more, and this moment, the decay of direct current signal was more little, and its direct current is big more.
DC level switching circuit 504 comprises amplifier 512, amplifier 514 and amplifier 516.Amplifier 516 is emitter followers.PWR1 is a normal voltage, and amplifier 512 provides zeroing function by dividing potential drop.When the DC level of direct current signal is higher than normal voltage, heighten the output voltage of direct current signal; When the DC level of direct current signal is lower than normal voltage, turn down the output voltage of direct current signal.Amplifier 514 is responsible for adjusting gain amplifiers, makes when transmission line 204 is the longest the magnitude of voltage maximum that amplifier 514 is exported.
After direct current signal is changed through DC voltage converting circuit 504, the input analog-to-digital conversion circuit, for example the eigth bit analog digital quantizer 522.Analog-digital converter 522 becomes numerical value with the voltage transitions of direct current signal.This numerical value is transfused to the line length counting circuit, and what this preferred embodiment was used is central processing unit 208.
Because the standard square-wave signal only just has effect when vertical synchronizing signal is effective, so vertical synchronizing signal also together inserts in the central processing unit 208, as shown in Figure 2.Have only when vertical synchronizing signal is effective, central processing unit 208 just carries out the computing of this numerical value.Central processing unit 208 is according to these data, calculates the length of transmission line 204 by method such as table look-up.Then, the chrominance signal compensating circuit carries out follow-up signal compensation deals such as the gain amplifier adjustment of chrominance signal or frequency compensation adjustment according to the length of transmission line 204.
This preferred embodiment when heavy straight synchronizing signal is effective with standard square-wave signal superposition in another not in the chrominance signal of superposition level or vertical synchronizing signal, and calculate the length of transmission line through the attenuation degree after transmission line according to this standard square-wave signal.Because when vertical synchronizing signal was effective, the electronic signal of this other superposition can not show any picture on display, therefore can not cause any interference to the user.
Moreover this preferred embodiment makes full use of in the transmission line idle originally bandwidth, has improved that prior art must take the sub-line of UART and problems such as the reduction communication bandwidth that causes and signal delay.And the employed electronic component structure of this preferred embodiment is simple, with low cost and be easy to use, and cooperates the decay of the analog signal that compensation that signal compensation apparatus can be effective and correct causes owing to the line length of transmission line.
Though the present invention by the preferred embodiment explanation as above, this preferred embodiment is not in order to limit the present invention.Those skilled in the art without departing from the spirit and scope of the present invention, should have the ability this preferred embodiment is made various changes and replenished, so protection scope of the present invention is as the criterion with the scope of claims.
Being simply described as follows of symbol in the accompanying drawing:
100: Line length measurer 102: signal synthesis circuit
104: transmission line 106: signaling conversion circuit
108: line length counting circuit 204: transmission line
206: signaling conversion circuit 208: central processing unit
210: signal synthesis circuit 212: video signal output apparatus
214:8MHz signal generator 216: signal receiving circuit
222: chrominance signal restore circuit 224: the chrominance signal compensating circuit
232: level and vertical synchronizing signal are extracted circuit
234:8MHz signal extracting circuit 240: image signal output end
242: display 302: the frequency elimination element
304: differential circuit 402: semiconductor
404: semiconductor 502: filter circuit
504: DC level switching circuit 512: amplifier
514: amplifier 516: amplifier
522: analog-digital converter
Claims (10)
1. Line length measurer of measuring the length of transmission line of transmission video signal, wherein this vision signal has three chrominance signals, a horizontal-drive signal and a vertical synchronizing signal, this transmission line has three antithetical phrase lines and is used for transmitting three chrominance signals respectively, on horizontal-drive signal and vertical synchronizing signal two chrominance signals that superposition to three antithetical phrase line is transmitted respectively.It is characterized in that this Line length measurer comprises at least:
A signal synthesis circuit, when vertical synchronizing signal is effective, with a standard square-wave signal superposition to another not in the chrominance signal that sub-line transmitted of superposition horizontal-drive signal or vertical synchronizing signal, and the chrominance signal of superposition standard square-wave signal has converted a differential wave to;
The differential primary circuit of going back will be reduced into a single-wire signal through the differential wave after this sub-line transmission;
A signaling conversion circuit converts this single-wire signal to a numerical value; And
A line length counting circuit goes out the line length of this transmission line according to this numerical computations.
2. Line length measurer according to claim 1, it is characterized in that: this measurement mechanism comprises a signal extracting circuit, from the chrominance signal of superposition vertical synchronizing signal, extract vertical synchronizing signal, when the vertical synchronizing signal of extracting was effective, the line length counting circuit calculated the line length of this transmission line.
3. Line length measurer according to claim 1 is characterized in that: this signaling conversion circuit comprises:
A filter circuit is filtered into direct current signal with single-wire signal;
A DC level switching circuit is adjusted the DC level of this direct current signal; And
An analog-to-digital conversion circuit converts this direct current signal of adjusted DC level to numerical value.
4. line length method of measurement of measuring the length of transmission line of transmission video signal is characterized in that this line length method of measurement comprises at least:
When the vertical synchronizing signal in the vision signal is effective, with an electronic signal superposition to three chrominance signals of this vision signal;
To convert a numerical value through this electronic signal after this transmission line to; And
Go out the line length of this transmission line according to this numerical computations.
5. line length method of measurement according to claim 4 is characterized in that: when the horizontal-drive signal in this vertical synchronizing signal and the vision signal was distinguished superposition in two chrominance signals, this electronic signal superposition was to remaining chrominance signal.
6. line length method of measurement according to claim 4 is characterized in that: this electronic signal is a standard square-wave signal, and the frequency range of this standard square-wave signal and is advisable with 8MHz between about 4MHz to 12MHz.
7. line length method of measurement according to claim 4 is characterized in that this switch process comprises:
To be filtered into a direct current signal through this electronic signal after this transmission line;
Adjust the DC level of this direct current signal; And
Convert this direct current signal of adjusted DC level to this numerical value.
8. line length method of measurement according to claim 7 is characterized in that this set-up procedure comprises:
Provide the DC level of a normal voltage and this direct current signal to make comparisons;
The DC level of this direct current signal and the difference of this normal voltage are big more, and the output voltage of this direct current signal is high more; And
The DC level of this direct current signal and the difference of this normal voltage are more little, and the output voltage of this direct current signal is low more.
9. line length method of measurement according to claim 4 is characterized in that this superposition step comprises:
Converting this electronic signal to a differential wave transmits at this transmission line; And
This differential wave after the transmission is reduced into a single-wire signal, converts this numerical value then to.
10. line length method of measurement according to claim 4, it is characterized in that: this line length method of measurement comprises from the chrominance signal of superposition vertical synchronizing signal and extracts this vertical synchronizing signal, and when this vertical synchronizing signal of being extracted is effective, calculate the line length of this transmission line.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100427728A CN100551085C (en) | 2004-05-26 | 2004-05-26 | A kind of Line length measurer and method of measurement thereof for the computer switch use |
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2004100427728A CN100551085C (en) | 2004-05-26 | 2004-05-26 | A kind of Line length measurer and method of measurement thereof for the computer switch use |
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| CN1705379A true CN1705379A (en) | 2005-12-07 |
| CN100551085C CN100551085C (en) | 2009-10-14 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103491388A (en) * | 2012-06-11 | 2014-01-01 | 株式会社东芝 | Video sender and video receiver |
| US10873717B2 (en) | 2011-10-20 | 2020-12-22 | Kabushiki Kaisha Toshiba | Communication device and communication method |
| CN112399098A (en) * | 2020-12-02 | 2021-02-23 | 龙迅半导体（合肥）股份有限公司 | Automatic configuration method and system for output signal intensity of HDMI transmitter |
-
2004
- 2004-05-26 CN CNB2004100427728A patent/CN100551085C/en active Active
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10873717B2 (en) | 2011-10-20 | 2020-12-22 | Kabushiki Kaisha Toshiba | Communication device and communication method |
| US11297277B2 (en) | 2011-10-20 | 2022-04-05 | Kabushiki Kaisha Toshiba | Communication device and communication method |
| CN103491388A (en) * | 2012-06-11 | 2014-01-01 | 株式会社东芝 | Video sender and video receiver |
| CN103491388B (en) * | 2012-06-11 | 2017-06-23 | 株式会社东芝 | Video transmitter and video receiver |
| US10341726B2 (en) | 2012-06-11 | 2019-07-02 | Toshiba Visual Solutions Corporation | Video sender and video receiver |
| CN112399098A (en) * | 2020-12-02 | 2021-02-23 | 龙迅半导体（合肥）股份有限公司 | Automatic configuration method and system for output signal intensity of HDMI transmitter |
| CN112399098B (en) * | 2020-12-02 | 2024-01-19 | 龙迅半导体（合肥）股份有限公司 | Automatic configuration method and system for output signal strength of HDMI transmitter |
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| CN100551085C (en) | 2009-10-14 |
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