CN101795147B - Method and device for reducing noise in twisted-pair connecting mode and network equipment - Google Patents
Method and device for reducing noise in twisted-pair connecting mode and network equipment Download PDFInfo
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Abstract
The invention provides a method and a device for reducing noise in a twisted-pair connecting mode and network equipment. The method comprises the following steps: receiving a digital signal; and when the digital signal is 0, setting currents output from a first output end and a second output end of a primary coil of an isolation transformer as a half of the sum of the currents output from the first output end and the second output end when the digital signal is 1 or -1. The device comprises a processing module and the isolation transformer connected with the processing module, wherein the processing module comprises a receiving unit and a processing unit; the receiving unit is used for receiving the digital signal; and the processing unit is used for setting currents output from the first output end and the second output end of the primary coil of the isolation transformer when the digital signal is 0 as a half of the sum of the currents output from the first output end and the second output end when the digital signal is 1 or -1. According to the technical scheme, a common-mode signal generated when an output signal changes can be reduced and the suppression of the common-mode signal is achieved.
Description
Technical field
The present invention relates to the communication technology, relate in particular to a kind of method, device and network equipment of reducing noise in twisted-pair connecting mode.
Background technology
In the switch of Ethernet, generally be transferred to physical chip via RJ45 connector, isolating transformer from the signal on the outside netting twine, perhaps the isolated signal of MAC layer passes through physical chip, and send into outside netting twine via isolating transformer, RJ45 connector, specifically as shown in Figure 1, wherein processing module is physical chip.Wherein, be at circuit printing plate (Print Circuit Board from the RJ45 connector to this section of physical chip circuit; Referred to as: PCB) upward realize, be used to the twisted-pair feeder on the connection line that interface is provided, be commonly referred to Media Dependent Interface (MediumDependent Interface; Referred to as: MDI).
Fig. 2 is the circuit structure diagram under the existing twisted pair line connection mode, as shown in Figure 2, processing module (being often referred to physical chip) adopts the outside transmitted signal of form of current source, physical chip (being processing module) the outwards needed electric current of transmitted signal is provided by external power source VCC, and external power source VCC is connected to the centre (being the centre cap place of isolating transformer primary coil) of isolating transformer primary coil.The presentation mode of existing drive current is: when processing module received numerical signal " 1 ", control external power source VCC provided drive current to first control end (namely just connecting line end) of processing module; When processing module received digital signal " 1 ", control external power source VCC provided drive current to its second control end (i.e. the negative line end that connects); When processing module received digital signal " 0 ", the control external power source VCC do not provide drive current to processing module.When Fig. 2 has provided processing module and has received digital signal " 1 ", current forms in the circuit, as shown in Figure 2, when processing module receives digital signal " 1 ", the drive current that external power source VCC provides flows to respectively positive connecting line and negative connecting line through centre cap, namely forms current i
1And current i
2, and current i
1And current i
2Size is 1: 3, current i
1Through behind two 50 ohm the resistance with current i
2Converge, and flow into the negative connection line end of processing module, to satisfy the demand of processing module required drive current when receiving digital signal " 1 ".
But, in the method for supplying of above-mentioned drive current, when the signal generation saltus step of processing module output (for example, between " 1 " signal and " 0 " signal, or between " 0 " signal and " 1 " signal saltus step occurs) time, the electric current of the first output of isolating transformer primary coil (being the coil on centre cap top) and the second output (being the coil of centre cap bottom) output can change.At this moment, because the leakage inductance that isolating transformer itself exists, when changing, electric current can produce mutation voltage, and because the curent change direction is identical, amplitude of variation is different, cause the change direction of mutation voltage identical, amplitude of variation is different, and producing a plurality of common-mode signals (noise) after the mutation voltage addition that change direction is identical, amplitude of variation is different, common-mode signal not only can cause serious electromagnetic interference (Electromagnetic Interference; Referred to as: EMI), also can have a strong impact on the quality of signal on the transmission line, and then affect the processing module of receiving terminal to the reception of signal.
And mostly prior art is that by adopting the realization of common mode inhibition device and some filter capacitors to the inhibition of common-mode signal, this mode can increase the complexity of circuit structure undoubtedly, and can increase the circuit design cost.
Summary of the invention
The invention provides a kind of method, device and the network equipment of reducing noise in twisted-pair connecting mode, in order to reduce the common-mode signal that produces when output digit signals changes, realize the inhibition to common-mode signal.
The invention provides a kind of method of reducing noise in twisted-pair connecting mode, comprising:
Receiving digital signals;
For digital signal " 0 ", half of the electric current sum of the first output and the output of the second output when the electric current of the first output of isolating transformer primary coil and the output of the second output all is set to digital signal for " 1 " or " 1 ".
The invention provides a kind of device of reducing noise in twisted-pair connecting mode, comprise processing module, with the isolating transformer that is connected with processing module; Described processing module comprises:
Receiving element is used for receiving digital signals;
Processing unit, be used for when receiving digital signal " 0 " half of the electric current sum of the first output and the output of the second output when the electric current of the first output of described isolating transformer primary coil and the output of the second output all is set to digital signal for " 1 " or " 1 ".
The invention provides a kind of network equipment, comprise the device of reducing noise in twisted-pair connecting mode provided by the invention.
The method of reducing noise in twisted-pair connecting mode of the present invention, device and the network equipment, by changing the send mode of the digital signal that existing processing module sends and receives with the current source form, when sending digital signal " 0 ", half of the electric current sum of the first output and the output of the second output when the first output by the isolating transformer primary coil is set and the electric current of the second output output are digital signal for " 1 " or " 1 ".Pass through technique scheme, when output signal changes, can make the first output identical with the rate of change of the electric current of the second output output, change in the opposite direction, so that the voltage jump that is produced when the curent change by the leakage inductance of isolating transformer can cancel out each other, and then eliminates common-mode signal, solved the electromagnetic interference that produces because of common-mode signal, reduce the noise in the signal, be conducive to improve receiving terminal to the quality of reception of signal.Simultaneously, compared with prior art, technical solution of the present invention also has the complexity that do not increase circuit design and the advantage of cost.
Description of drawings
In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art, the below will do one to the accompanying drawing of required use in embodiment or the description of the Prior Art and introduce simply, apparently, accompanying drawing in the following describes is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain according to these accompanying drawings other accompanying drawing.
Fig. 1 is the annexation figure under the existing twisted pair line connection mode;
Fig. 2 is the circuit structure diagram under the existing twisted pair line connection mode;
The flow chart of the method for the reducing noise in twisted-pair connecting mode that Fig. 3 provides for the embodiment of the invention one;
The schematic diagram of a kind of circuit structure of the implementation step 303 that Fig. 4 a provides for the embodiment of the invention one;
The schematic diagram of the another kind of circuit structure of the implementation step 303 that Fig. 4 b provides for the embodiment of the invention one;
Current diagram when Fig. 5 is the processing module output digit signals " 1 " of the embodiment of the invention two;
Current diagram when Fig. 6 is the processing module output digit signals " 0 " of the embodiment of the invention two;
The structural representation of the device of the reducing noise in twisted-pair connecting mode that Fig. 7 provides for the embodiment of the invention three.
Embodiment
For the purpose, technical scheme and the advantage that make the embodiment of the invention clearer, below in conjunction with the accompanying drawing in the embodiment of the invention, technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that obtains under the creative work prerequisite.
The flow chart of the method for the reducing noise in twisted-pair connecting mode that Fig. 3 provides for the embodiment of the invention one, the low noise method of falling of present embodiment is implemented based on circuit structure shown in Figure 2, specifically comprises:
In the present embodiment.Processing module can be the chip of physical layer in the switch, for example can receive from medium access control (Media Access Control; Referred to as: MAC) layer is resolved the digital signal of obtaining, and this digital signal is specially " 1 ", " 0 " or " 1 ".
For example, take circuit structure shown in Figure 2 as example, namely the first output by the isolating transformer primary coil and the second output export ratio are the electric current of 1: 3 or 3: 1, difference output digit signals " 1 " or " 1 ", and in following examples, all describe as an example of this ratio example, but be not limited to this, specifically can arrange according to the actual requirements or adjust.
Concrete, processing module is by the different electric current of isolating transformer output, represent different digital signals, for example, the first output by the isolating transformer primary coil and the second output output size are 1: 3 electric current, expression output digit signals " 1 ", the first output by the isolating transformer primary coil and the second output output size are 3: 1 electric current, expression output digit signals " 1 ".In the present embodiment, when output digit signals " 0 ", equate by the electric current that the output of the first output and the second output is set, and the size that electric current is set is digital signal 1 " or half of the electric current sum of " 1 " first output and the second output output; when the digital signal of output in " 0 " and 1 " or " 1 " between when changing, can be so that the first output be identical with the rate of change of the electric current of the second output output, change in the opposite direction the common-mode signal that produces to avoid therefore.
Present embodiment low noise method falls, the way of output of the drive current during by change processing module output digit signals " 0 ", make when the processing module output signal changes, isolating transformer primary coil the first output is identical with the current changing rate of the second output output, and change in the opposite direction, so that because the voltage jump equal and opposite in direction that isolating transformer self leakage inductance produces, opposite direction, with the common-mode signal of avoiding so producing, the electromagnetic interference of common-mode signal generation and the impact that signal is produced have been solved; Simultaneously, present embodiment solves the problem of common-mode signal by the mode that changes drive current, compares by the method for common mode inhibition device or filter capacitor with existing, can not increase complexity and the design cost of circuit structure.
Further, present embodiment provides a kind of execution mode of step 303, be specially: the electric current of the first output that can control respectively the isolating transformer primary coil by the first control end and second control end of processing module and the output of the second output, making the electric current of the first output and the second output output be digital signal is 1 " or half of the electric current sum of the first output and the output of the second output when " 1 ".
Concrete, present embodiment provides the realization of two kinds of above-mentioned execution modes in the side circuit design, but is not limited to this.Shown in Fig. 4 a, a kind of is that the first control end and the second control end in processing module is respectively equipped with the first earthed switch and the first current source, the first current source is connected with the first earthed switch, the first current source is adjustable current source, namely can adjust the current value of the first current source output, therefore, can realize respectively output digit signals " 1 ", " 0 " or " 1 " by controlling the first above-mentioned earthed switch and the first current source.
For example when output digit signals " 1 ", the first earthed switch of controlling the second control end is closed, and adjust the first current source output current of the second control end, the first output of driving isolation transformer and the second output export ratio are 1: 3 electric current, to realize output digit signals " 1 "; When output digit signals " 1 ", the first earthed switch of controlling the first control end is closed, and adjust the first current source output current of the first control end, the first output of driving isolation transformer and the second output export ratio are 3: 1 electric current, to realize output digit signals " 1 "; And when output digit signals " 0 ", then can be by respectively closed the first control end and the first earthed switch the second control end, and the electric current of adjusting the first current source the first control end and the second control end output to be digital signal be 1 " half of the electric current of the first current source output of corresponding the second control end; or be half of electric current of the first current source output of the first control end corresponding to digital signal " 1 "; take the electric current of the first output of controlling respectively the isolating transformer primary coil and the output of the second output as digital signal as 1 " or half of the electric current sum of the first output and the output of the second output when " 1 ", the electric current sum of the first output and the second output output was the current value of the first current source output of corresponding control end when wherein digital signal was for " 1 " or " 1 ".In this is realized, earthed switch and current source when the first above-mentioned earthed switch and the first current source are output digit signals " 1 " or " 1 ".
Shown in Fig. 4 b, be another kind of implementation: the first control end and the second control end are respectively arranged with the second earthed switch and the second current source, the second earthed switch and second source series connection, wherein the current value of the second current source output is immutable, pre-set according to physical circuit, the electric current of its output is that digital signal is 1 " or half of the electric current of corresponding the 3rd current source output when " 1 "; wherein, the 3rd current source required drive current when output digit signals " 1 " or " 1 " are provided of connecting with the 3rd earthed switch.Then can be by respectively closed the first control end and the second earthed switch the second control end, and by the first control end and the second current source described the second control end, take half of the electric current sum of the electric current of the first output of controlling respectively the isolating transformer primary coil and the output of the second output the first output and the output of the second output as digital signal as " 1 " or when " 1 ", wherein the electric current sum of the first output and the output of the second output is the current value of corresponding the 3rd current source output when digital signal " 1 " or " 1 ".In this is realized, the second above-mentioned earthed switch with the second current source the 3rd earthed switch during from output digit signals " 1 " or " 1 " different with the 3rd current source.Wherein, can be respectively at the first control end and the second control end the series circuit of the 3rd earthed switch and the 3rd current source be set, the drive current so that output digit signals " 1 " or " 1 " to be provided.For example when output digit signals " 1 ", can be by the 3rd earthed switch of closed the second control end, by the 3rd current source output current, take the first output of control isolating transformer primary coil and the second output export ratio electric current as 1: 3, realize the output of digital signal " 1 "; When output digit signals " 1 ", can be by the 3rd earthed switch of closed the first control end, and by the 3rd current source output current, take the first output of control isolating transformer primary coil and the second output export ratio electric current as 3: 1, realize the output of digital signal " 1 ".
Numerical analysis below in conjunction with concrete further specifies technical solution of the present invention.
When processing module receives digital signal " 1 ", processing module provides drive current with output digit signals " 1 " by external power source VCC, isolating transformer, present embodiment is with the electric current of isolating transformer primary coil output 40mA, the electric current that is the second control end reception 40mA of processing module is example, and present embodiment peripheral power supply VCC is made as 1.8V.Concrete, in conjunction with shown in Figure 2, processing module disconnects by the earthed switch of control the first control end, the earthed switch of the second control end is closed, make external power source VCC provide drive current to processing module, as shown in Figure 2, the drive current that provides of external power source VCC flows to respectively the current i of the first control end through centre cap
1With the current i that flows to the second control end
2, current i
1By behind two 50 ohm the resistance and current i
2Converge the second control end that flows into processing module.
At first, the inductance of elementary half number of turn of main coil of definition isolating transformer is L, and then the inductance of secondary whole numbers of turn is 4L, and then the combined potential in the loop of two the 50 Europe resistance in the left side and primary coil formation is zero, then:
jwLi
1+i
1R-jwLi
2+jwMi
3＝jwLi
2-jwLi
1-jwMi
3 (1)
Wherein,
i
3Be the couple current of primary coil in the secondary coil generation.
The right secondary coil and two loops that 50 Europe ohmic loads consist of, the combined potential in loop is zero:
jw4Li
3+jwMi
1-jwMi
2+i
3R＝0 (2)
Abbreviation formula (1) and formula (2) can get:
2jwLi
1+i
1R-2jwLi
2+4jwLi
3＝0 (3)
2jwLi
1+i
3R-2jwLi
2+4jwLi
3＝0 (4)
Can be drawn by formula (3) and formula (4):
i
1＝i
3 (5)
With formula (5) substitution formula (4) or formula (3), can get:
In 1000Base-T, the frequency of signal concentrates on tens to 100,000,000 scope, and inductance L is generally about 150uf, so the impedance that coil presents is generally several kilo-ohms of levels, and resistance R is 100 Europe, so second in the formula (6) can ignore, then can get:
i
2≈3i
1 (7)
Finally can get: i
1=10mA, i
2=30mA, i
3=10mA.
When processing module receives digital signal " 1 ", processing module provides drive current with output digit signals " 1 " by external power source VCC, isolating transformer, from the above, present embodiment is when output digit signals " 1 ", the electric current of isolating transformer primary coil output 40mA, namely the first control end of processing module receives the electric current of 40mA.Concrete, processing module is closed by the earthed switch of control the first control end, the earthed switch of the second control end disconnects, make external power source VCC provide drive current to processing module, as shown in Figure 5, the drive current that provides of external power source VCC flows to respectively the current i of the first control end through centre cap
1With the current i that flows to the second control end
2, current i
2By behind two 50 ohm the resistance and current i
1Converge the first control end that flows into processing module.
By derivation similar to the above, finally can get: i
1=30mA, i
2=10mA, i
3=10mA.
When drive current is provided in the above described manner with output digit signals " 1 " or " 1 ", current i
1And current i
2Ratio be 1: 3 or 3: 1, ratio is unbalanced.When processing module receives digital signal " 0 ", processing module provides drive current with output digit signals " 0 " by external power source VCC, isolating transformer, the mode output digit signals " 0 " of the drive current that first control end and second control end of present embodiment by processing module sucks 20mA simultaneously.For example, can be by the earthed switch of closed the first control end of while and the second control end, make the external power source VCC while be formed into the path on ground at the first control end and the second control end, and by the size of the current source of inside control electric current, wherein current forms as shown in Figure 6, drive current that external power source VCC provides flows to respectively the current i of the first control end through centre cap
1With the current i that flows to the second control end
2, and current i in the present embodiment
1And current i
2Big or small identical, be 20mA.
Based on this, when changing from " 1 " to " 0 " from the digital signal of output, the current i of the first output output
1Become 20mA by 30mA, being changed to-10mA of unit interval; The current i of the second output output
2Become 20mA by 10mA, being changed to+10mA of unit interval; Hence one can see that, and the first output is identical with the current changing rate of the second output output, and changes in the opposite direction.After the signal of output was affected by the isolating transformer leakage inductance like this, the voltage jump amplitude was symmetrical, and the sudden change opposite direction is cancelled out each other after the voltage jump addition of the first output and the second output, has reduced common-mode signal.Simultaneously, become " 0 " by " 1 " or from " 0 " to " 1 " or " 1 " when conversion, adopt technical solution of the present invention also can eliminate common-mode signal when the digital signal of output.
By above-mentioned analysis, the mode of the drive current when technical solution of the present invention is by change output digit signals " 0 " as can be known, so that isolating transformer primary coil the first output is identical with the current changing rate of the second output output, change in the opposite direction, so that be subjected to the isolating transformer leakage inductance to affect the sudden change amplitude symmetry of the mutation voltage of rear generation, opposite direction can be cancelled out each other after the mutation voltage addition, has reduced common-mode signal.
The structural representation of the device of the reducing noise in twisted-pair connecting mode that Fig. 7 provides for the embodiment of the invention three, as shown in Figure 7, the device of present embodiment comprises: processing module 61 and the isolating transformer 62 that is connected with processing module 61.Wherein processing module 61 comprises receiving element 601, is used for receiving digital signals, for example digital signal " 1 ", " 0 " or " 1 "; And processing unit 602, be used for when receive digital signal " 0 " half of the electric current sum that the first output 621 and the second output 622 were exported when the electric current of the first output 621 of isolating transformer primary coil and 622 outputs of the second output all was set to digital signal for " 1 " or " 1 ".Wherein, the processing module of present embodiment can be the chip of the physical layer in the switch.
Further, the processing unit 602 of present embodiment can comprise the first control end 611 and the second control end 612 when specific implementation.Wherein, the first control end 611 and the second control end 612 can be made of the first earthed switch and the first current source, the first earthed switch and the first current source are cascaded, and the size of the electric current of the first current source output can be regulated, therefore, can be half of electric current sum of digital signal the first output 621 and 622 outputs of the second output when being " 1 " or " 1 " by the electric current of regulating the first current source output, realize that the first output 621 of control isolating transformer 62 primary coils and the electric current of the second output 622 outputs are that digital signal is 1 " or half of the electric current sum of the first output 621 and 622 outputs of the second output when " 1 ".Earthed switch and current source when above-mentioned the first earthed switch and the first current source can adopt output digit signals " 1 " or " 1 ".
In addition, the first control end 611 in the technical solution of the present invention and the second control end 612 also can be made of the second earthed switch and the second current source, the second earthed switch and the second current source are cascaded, and the electric current of the second current source output sets according to circuit structure and design requirement in advance, the electric current of i.e. the second current source output is immutable, and the electric current of in the present embodiment the second current source output is that digital signal is 1 " or half of the electric current sum of the first output 621 and 622 outputs of the second output when " 1 ".And earthed switch and current source when the second earthed switch and the second current source can be from output digit signals " 1 " or " 1 " are different.
What deserves to be explained is that at this falling low noise device can also comprise various auxiliary peripheral circuits in concrete application of present embodiment is such as the peripheral circuit that is made of devices such as resistance, filter capacitors, in Fig. 7 and not shown.
Present embodiment low noise device falls, processing unit is when receiving digital signal " 0 ", half of the electric current sum of the first output and the output of the second output when the electric current of the first output of isolating transformer primary coil and the output of the second output all is set to digital signal for " 1 " or " 1 ", so that change from " 1 " or " 1 " to " 0 " or from " 0 " to " 1 " or " 1 " when changing in the digital signal of output, the first output of isolating transformer primary coil is identical with the current changing rate of the second output output, and changes in the opposite direction.After the signal of output was affected by the isolating transformer leakage inductance like this, the voltage jump amplitude was symmetrical, and the sudden change opposite direction is cancelled out each other after the voltage jump addition of the first output and the second output, has reduced common-mode signal.Simultaneously, compare with existing method by common mode inhibition device and filter capacitor inhibition common-mode noise, technical solution of the present invention is simpler in realization, can not increase the complexity of circuit structure.
The embodiment of the invention four provides a kind of network equipment, the network equipment of present embodiment comprises the device of the reducing noise in twisted-pair connecting mode that the embodiment of the invention provides, and can implement the method for the reducing noise in twisted-pair connecting mode that the embodiment of the invention provides, therefore, the network equipment that adopts present embodiment to provide, can reduce common-mode signal equally, reduce the electromagnetic interference that common-mode signal causes, improve the quality that receives signal.Concrete, the network equipment of present embodiment can be switch, namely this switch comprises the device of reducing noise in twisted-pair connecting mode provided by the invention, and by carrying out the method for reducing noise in twisted-pair connecting mode provided by the invention, can reduce the common-mode signal that switch produces when output digit signals changes, reduce the electromagnetic interference that common-mode signal causes.
One of ordinary skill in the art will appreciate that: all or part of step that realizes said method embodiment can be finished by the relevant hardware of program command, aforesaid program can be stored in the computer read/write memory medium, this program is carried out the step that comprises said method embodiment when carrying out; And aforesaid storage medium comprises: the various media that can be program code stored such as ROM, RAM, magnetic disc or CD.
It should be noted that at last: above embodiment only in order to technical scheme of the present invention to be described, is not intended to limit; Although with reference to previous embodiment the present invention is had been described in detail, those of ordinary skill in the art is to be understood that: it still can be made amendment to the technical scheme that aforementioned each embodiment puts down in writing, and perhaps part technical characterictic wherein is equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution break away from the spirit and scope of various embodiments of the present invention technical scheme.
Claims (7)
1. the method for a reducing noise in twisted-pair connecting mode is characterized in that, comprising:
Receiving digital signals;
For digital signal " 0 ", half of the electric current sum of the first output and the output of the second output when the electric current of the first output of isolating transformer primary coil and the output of the second output all is set to digital signal for " 1 " or " 1 "; Half of the electric current sum that the first output and the second output were exported when the electric current of wherein, the first output and second output of isolating transformer primary coil being exported all was set to digital signal for " 1 " or " 1 " is specially:
The electric current of the first output of controlling respectively described isolating transformer primary coil by the first control end and second control end of processing module and the output of the second output, half of the electric current sum of the first output and the output of the second output when making the electric current of described the first output and the second output output be digital signal for " 1 " or " 1 ".
2. the method for reducing noise in twisted-pair connecting mode according to claim 1, it is characterized in that, the electric current of described the first output of controlling respectively described isolating transformer primary coil by the first control end and second control end of processing module and the output of the second output, half of the electric current sum of the first output and the output of the second output is specially when making the electric current of described the first output and the second output output be digital signal for " 1 " or " 1 ":
Respectively closed described the first control end and the first earthed switch described the second control end, and half of the electric current of the electric current of adjusting the first current source described the first control end and described the second control end output corresponding the first current source output described the second control end or described the first control end when being digital signal for " 1 " or " 1 ", take the electric current of the first output of controlling respectively described isolating transformer primary coil and the output of the second output as digital signal as 1 " or half of the electric current sum of the first output and the output of the second output when " 1 ".
3. the method for reducing noise in twisted-pair connecting mode according to claim 1, it is characterized in that, the electric current of described the first output of controlling respectively described isolating transformer primary coil by the first control end and second control end of processing module and the output of the second output, half of the electric current sum of the first output and the output of the second output is specially when making the electric current of described the first output and the second output output be digital signal for " 1 " or " 1 ":
Respectively closed described the first control end and the second earthed switch described the second control end, and by described the first control end and the second current source described the second control end, take half of the electric current sum of the electric current of the first output of controlling respectively described isolating transformer primary coil and the output of the second output the first output and the output of the second output as digital signal as " 1 " or when " 1 ", the output current of described the second current source is half of electric current of digital signal corresponding the 3rd current source output when being " 1 " or " 1 ".
4. the device of a reducing noise in twisted-pair connecting mode comprises processing module, and the isolating transformer with described processing module is connected is characterized in that, described processing module comprises:
Receiving element is used for receiving digital signals;
Processing unit, be used for when receiving digital signal " 0 " half of the electric current sum of the first output and the output of the second output when the electric current of the first output of described isolating transformer primary coil and the output of the second output all is set to digital signal for " 1 " or " 1 "; Half of the electric current sum that the first output and the second output were exported when the electric current of wherein, the first output and second output of isolating transformer primary coil being exported all was set to digital signal for " 1 " or " 1 " is specially:
The electric current of the first output of controlling respectively described isolating transformer primary coil by the first control end and second control end of described processing module and the output of the second output, half of the electric current sum of the first output and the output of the second output when making the electric current of described the first output and the second output output be digital signal for " 1 " or " 1 ".
5. the device of reducing noise in twisted-pair connecting mode according to claim 4 is characterized in that, described processing unit comprises: described the first control end and described the second control end that are made of the first earthed switch and the first current source; Described the first current source is adjustable current source.
6. the device of reducing noise in twisted-pair connecting mode according to claim 4 is characterized in that, described processing unit comprises: described the first control end and described the second control end that are made of the second earthed switch and the second current source; The electric current of described the second current source output is half of electric current of digital signal corresponding the 3rd current source output when being " 1 " or " 1 ".
7. a network equipment is characterized in that, comprises the device such as each described reducing noise in twisted-pair connecting mode of claim 4-6.
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|---|---|---|---|
| CN 201010144598 CN101795147B (en) | 2010-04-08 | 2010-04-08 | Method and device for reducing noise in twisted-pair connecting mode and network equipment |
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| CN 201010144598 CN101795147B (en) | 2010-04-08 | 2010-04-08 | Method and device for reducing noise in twisted-pair connecting mode and network equipment |
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| CN101795147A CN101795147A (en) | 2010-08-04 |
| CN101795147B true CN101795147B (en) | 2013-04-24 |
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| CN 201010144598 Expired - Fee Related CN101795147B (en) | 2010-04-08 | 2010-04-08 | Method and device for reducing noise in twisted-pair connecting mode and network equipment |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101030735A (en) * | 2006-03-01 | 2007-09-05 | 洛克威尔自动控制技术股份有限公司 | Improved power converter with reduced common mode voltage |
| CN101094534A (en) * | 2007-07-20 | 2007-12-26 | 成都理想信息产业有限责任公司 | Ethernet switchboard power fed from user end |
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| US6459739B1 (en) * | 1999-12-30 | 2002-10-01 | Tioga Technologies Inc. | Method and apparatus for RF common-mode noise rejection in a DSL receiver |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101030735A (en) * | 2006-03-01 | 2007-09-05 | 洛克威尔自动控制技术股份有限公司 | Improved power converter with reduced common mode voltage |
| CN101094534A (en) * | 2007-07-20 | 2007-12-26 | 成都理想信息产业有限责任公司 | Ethernet switchboard power fed from user end |
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