CN101262251A - Passive echo elimination device and its signal receiving/transmission method - Google Patents
Passive echo elimination device and its signal receiving/transmission method Download PDFInfo
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- CN101262251A CN101262251A CNA2007100862130A CN200710086213A CN101262251A CN 101262251 A CN101262251 A CN 101262251A CN A2007100862130 A CNA2007100862130 A CN A2007100862130A CN 200710086213 A CN200710086213 A CN 200710086213A CN 101262251 A CN101262251 A CN 101262251A
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Abstract
The invention relates to a passive echo elimination device which is used for a full duplex communication system, and a signal transmitting and receiving method thereof. The full duplex communication system comprises a sending terminal which is used for sending a transmit signal to a wire interface, and a receiving terminal which is used for receiving a received signal from the wire interface. The passive echo elimination device comprises a set-off signal generating circuit and a passive echo elimination circuit which is composed of a plurality of passive components. The signal set-off generating circuit is used for generating a set-off signal corresponding to the transmitting signal. The passive echo elimination circuit is connected between the wire interface and the receiving terminal in series and connected to the set-off signal generating circuit. The passive echo elimination circuit can capture the set-off signal so as to offset an echo signal in the received signal from the wire interface, thus generating an output signal only containing the signal characteristics of the received signal.
Description
Technical field
The present invention relates to communication system, particularly relate to a kind of echo cancellation (Echo Cancellation) apparatus and method.
Background technology
Because the progress of science and technology, the application of internet is also more and more wide.More and more big in view of the frequency range of network is required, the Ethernet that is commonly used at present (Ethernet), the transfer rate of its packet also is promoted to more than the 1Gbps from the past 10/100Mbps.
With at present common Gigabit Ethernet (Gigabit Ethernet) device is example, is in the Gigabit Ethernet device of 1Gbps in transmission rate, and each connectivity port (port) has four passages (channel).Each passage has a conveyer (transceiver), utilizes transmission medium, for example includes the cable (cable) of twisted-pair feeder (twist pair), links up with other network equipment.And each conveyer generally includes a transmission end and a receiving terminal.Wherein, the transmission end deal with data also is sent to long-range another network equipment by transmission medium with data, and receiving terminal then receives and handle the data that send by transmission medium.According to the standard of Gigabit Ethernet, each device uses four channels and other network equipment to link up simultaneously, and each channel is carried out the function of transmission and reception simultaneously, that is Gigabit Ethernet is an a kind of full duplex communication system.
Being as the characteristic of the full duplex communication system of Gigabit Ethernet etc. that each passage is carried out simultaneously transmits and receiving function.Yet in such system, can take place when network equipment desires to capture on the self-channel reception signal Rx, can be subjected to the influence of the transmission signal Tx that on same passage, sends out simultaneously, and be difficult to judge that the true complexion that receives signal, this phenomenon are commonly referred to as echo and disturb (EchoImpairment).Minimum for the echo disturbing effect is dropped to, can use echo cancellation circuit coupling (Echo Cancellation Circuit) that the transmission signal composition in the signal that is received is removed in the general networking device.
Present existing echo cancellation circuit coupling is provided with the active element as operational amplifier, transistor etc., uses active element, makes echo cancellation circuit coupling after eliminating echo effect, and initiatively gain also can be provided the signal that is received.Yet the use of active element causes the higher relatively and shortcoming of power consumption etc. comparatively of circuit design relative complex, cost also.
Summary of the invention
The purpose of this invention is to provide a kind of passive echo elimination device and signal receiving/transmission method thereof that is used for the full duplex communication system, it only need use some passive type assemblies and cooperate simple circuit design, can reach the purpose that the echo that eliminate to receive in the signal is disturbed, and can have that circuit design is simple relatively, cost is relatively low and the effect of power saving etc. comparatively.
For achieving the above object, signal receiving/transmission method of the present invention includes the following step:
One transmitting-receiving path is provided;
On this transmitting-receiving path, receives signal and transmit signal, to such an extent as to produce an echo signal that forms by the overlapping of this reception signal and this transmission signal;
The one counteracting signal that includes the signal feature of this transmission signal is provided; And
Use an echo cancellation circuit coupling that only includes the passive type assembly, eliminate this transmission signal in this echo signal, to produce an output signal that includes the signal feature of this reception signal according to this counteracting signal.
For achieving the above object, the passive echo elimination device that is used for the full duplex communication system of the present invention, this full duplex communication system includes a transmission end in order to transmitting signal to a line interface, and a receiving terminal receives signal in order to this line interface certainly.This passive echo elimination device includes one and offsets a signal generating circuit and a passive type echo cancellation circuit coupling.Utilize this counteracting signal generating circuit to produce and offset signal corresponding to one of this transmission signal.And this passive type echo cancellation circuit coupling only is made of some passive type assemblies (for example resistance or electric capacity), it can be offset after signal generating circuit captures this counteracting signal certainly, merge mutually with this reception signal that receives from line interface again, use the echo signal of payment in this reception signal, to produce an output signal that only includes the signal feature of this reception signal.
In a preferred embodiment, the transmission signal of this transmission end is produced by a gleam of driver, and this counteracting signal generating circuit be a pressure reduction circuit its be serially connected with between transmission end and the line interface.
In a preferred embodiment, the transmission signal of this transmission end is produced by a current type digital analog converter, and, this offset signal generating circuit be this current type digital analog converter a duplicate circuit its in order to generation this counteracting signal with the identical voltage of this transmission signal.
In a preferred embodiment, this passive type echo cancellation circuit coupling includes:
One first passive component, one end are coupled on the node between transmission end and the line interface;
One second passive component, one end are coupled in the output of offsetting signal generating circuit;
One the 3rd passive component, one end are coupled in another output of offsetting signal generating circuit; And,
One the 4th passive component, one end are coupled on another node between transmission end and the line interface;
Wherein, first passive component is connected with the other end of second passive component and constitutes one first output, and the 3rd passive component also is connected with the other end of the 4th passive component and constitute one second output, and this first and second output is coupled in this receiving terminal;
Wherein, this first to fourth passive component can be following one of them: resistance and electric capacity.
Description of drawings
Figure 1A is the circuit diagram of first embodiment of passive echo elimination device of the present invention.
Figure 1B is the circuit diagram of first embodiment under signal sampling mode state of passive echo elimination device of the present invention.
Fig. 1 C keeps circuit diagram under the mode state for first embodiment of passive echo elimination device of the present invention in signal.
Fig. 2 A is the circuit diagram of second embodiment of passive echo elimination device of the present invention.
Fig. 2 B is the circuit diagram of second embodiment under signal sampling mode state of passive echo elimination device of the present invention.
Fig. 2 C keeps circuit diagram under the mode state for second embodiment of passive echo elimination device of the present invention in signal.
Fig. 3 is the circuit diagram of the 3rd embodiment of passive echo elimination device of the present invention.
Fig. 4 is the circuit diagram of the 4th embodiment of passive echo elimination device of the present invention.
The reference numeral explanation
31,31a transmission end
313 current type digital analog converters
3131～313n converting unit
314 duplicate circuits
32 line interfaces
33 receiving terminals
34 twisted-pair feeders
35 line drives
36,46 sample-and-hold circuits
361～364 electric capacity
37 state amplifiers
41 pressure reduction circuit
42,42a, 52,52a passive type echo cancellation circuit coupling
421～426,421a～424a resistance
521～524,521a～524a electric capacity
901～906 nodes
907 ground connection
Embodiment
In order more clearly to describe passive echo elimination device proposed by the invention and method, below will enumerate embodiment and describe passive echo elimination device of the present invention in detail, and the detailed description of occupation mode, and technical characterictic of the present invention.
See also Figure 1A, Figure 1B and Fig. 1 C.Wherein, Figure 1A is the circuit diagram of first embodiment of passive echo elimination device of the present invention; Figure 1B is the circuit diagram of passive echo elimination device of the present invention under signal sampling mode (sample mode) state shown in Figure 1A; Fig. 1 C then keeps circuit diagram under pattern (holdmode) state for passive echo elimination device of the present invention shown in Figure 1A in signal.
The full duplex communication system comprises that a transmission end 31 receives signal in order to transmit signal to a line interface 32 and a receiving terminal 33 in order to this line interface 32 certainly.In transmission end 31, can be provided with and comprise that (Digital-to-Analog Converter DAC) waits assembly to digital analog converter.(Analog Front End, AFE) (Analog-to-Digital Converter ADC) waits assembly for circuit and analog-digital converter then can be provided with AFE (analog front end) in receiving terminal.This line interface is in order to connect a twisted-pair feeder 34 for being connected to long-range another network equipment.Because this described transmission end 31, line interface 32, and the execution mode of receiving terminal 33 know for those skilled in the art extensively knows, so will not give unnecessary details.
In first embodiment shown in Figure 1A, form the assembly except aforementioned each, in order to reach the purpose of echo cancellation, also include a pressure reduction circuit 41 and a passive type echo cancellation circuit coupling 42.In present embodiment, 31 output is the digital analog converter that is used as transmission end 31 with a gleam of driver 35 in the transmission end, produce and transmit signal, realize digital-to-analogue conversion with line drive, its detailed architecture and operation principles be the person of knowing that those skilled in the art extensively knows, so will not given unnecessary details at this.In present embodiment, owing to be 1/2nd of resistance with two resistance R a in the pressure reduction circuit 41 equivalent resistance Rc that is made as line interface 32, for example Ra is that 50 ohm, Rc are 100 ohm, then according to the law of partial pressure, if the transmission signal that is sent out on second, third node 902,903 is Tx, line drive 35 is output in the 2Tx that signal on the first, the 4th node 901,904 is the twice amplitude.And also can pass on second, third node 902,903 by line interface 32 owing to coming from outside reception signal Rx, the signal of on second, third node 902,903, being seen then, real in transmitting signal Tx and the overlapping result (superimposition) who receives signal Rx, i.e. Tx+Rx.
In sum, because being respectively, the signal that is positioned at pressure reduction circuit 41 two ends transmits signal and the overlapping that receives signal Tx+Rx and fixing multiplying power (the being twice) 2Tx that transmits signal as a result, then the signal value at pressure reduction circuit 41 two ends can be used for carrying out the operation of echo cancellation by acquisition, and obtains actual reception signal Rx.In present embodiment, pressure reduction circuit 41 constitutes one in the passive echo elimination device of the present invention in fact and offsets signal generating circuit, just can be used to produce a counteracting signal person who only includes the composition that transmits signal Tx.Shown in Figure 1A, the passive type echo cancellation circuit coupling 42 of present embodiment is made up of some passive components, and be serially connected with between line interface 32 and the receiving terminal 33, between the digital analog converter (DAC) that also is positioned at simultaneously transmission end 31 and the analog-digital converter (ADC) of receiving terminal 33, it includes some resistance 421～426 (called after first to the 6th resistance in regular turn) and suitable circuit connection.
As shown in the figure, an input of first resistance 421 is coupled in the 3rd node 903 between pressure reduction circuit 41 and the line interface 32.One input of second resistance 422 is coupled in the first node 901 between pressure reduction circuit 41 and the transmission end 31.One input of the 3rd resistance 423 is coupled in the 4th node 904 between pressure reduction circuit 41 and the transmission end 31.One input of the 4th resistance 424 is coupled in the Section Point 902 between pressure reduction circuit 41 and the line interface 32.First resistance 421 is connected with the other end of second resistance 422 and constitutes one first output (the 5th node 905), and the 3rd resistance 423 also is connected with the other end of the 4th resistance 424 and constitute one second output (the 6th node 906).And this first and second output is kept (sample and hold) circuit 36 by a sampling and is coupled to receiving terminal 33.In addition, an end of the 5th resistance 425 and the 6th resistance 426 is connected to this first output and this second output respectively, and the other end of the 5th resistance 425 and the 6th resistance 426 ground connection 907 then.
In present embodiment, transmit the influence that signal Rx is received in signal Tx butt joint in order to remove effectively, be positioned at the signal 2Tx at pressure reduction circuit 41 two ends and Tx+Rx as mentioned above, input in the echo cancellation circuit coupling 42 with phase inversion system, and to transmit signal components in proportions poor (being twice) therebetween in order compensating, then to be made as R together as if resistance value with first resistance 421 and the 4th resistance 424
1, the resistance value of second resistance 422 and the 3rd resistance 423 is with being made as 2R
1Be all R if establish the resistance value of the 5th resistance 425 and the 6th resistance 426 again
2, by voltage divider principle, the signal value that just can calculate the 6th node 906 places is as shown in the formula (1):
In like manner, the signal value at the 5th node 905 places is then as shown in the formula (2):
That is to say, when signal through after this passive type echo cancellation circuit coupling 42, can obtain an output signal and receive signal Rx in proportion to and (Rx), make that contained echo is disturbed in the former reception signal to be able to be offseted, and reach the echo cancellation effect.Because the passive type echo cancellation circuit coupling 42 of present embodiment only uses passive type assembly such as resistance and simple circuit design, so, compared to the prior art of aforementioned use active element, the passive echo elimination device of present embodiment can have more that circuit design is simple relatively, cost is relatively low and the advantage person of power saving etc. comparatively.
Note that the echo cancellation circuit coupling 42 in the present embodiment also can be designed to adjustable resistance (variable resistor) with the 5th, six resistance 425,426 and/or first, second, third and fourth resistance 421-424, by adjusting resistance value R
1And R
2Between ratio decide the voltage gain value of being desired, though because echo cancellation circuit coupling 42 realizes with the passive type assembly fully, its voltage gain value can only be the value less than 1, but progress along with integrated circuit technology, employed operating voltage also more develops toward the direction of low-voltage, therefore for advanced technology, 0.18 μ m standard CMOS process or more advanced for example, be the littler technology of size, the needs that amplify of the signal that receives into of no-trump, the amplitude of signal must be dwindled (promptly using voltage gain value) on the contrary, could cooperate the operation of subsequent conditioning circuit less than 1.Therefore, the passive type echo cancellation circuit coupling 42 in the present embodiment is particularly suitable for being used in the middle of the advanced technology.
Through the output signal that processing produced of echo cancellation circuit coupling 42, promptly only include the composition that receives signal Rx, and be transferred into the first order circuit of receiving terminal 33 again, in present embodiment sample-and-hold circuit 36.As skilled in the art to understand, sample-and-hold circuit 36 is the first order circuit of the analog-digital converter in the receiving terminal 33 usually, it is by the switching of two opposite a plurality of switches of clock signal ψ, ψ ' control of phase place, repeatable operation is kept between the pattern at a sampling mode and, its be when this sampling mode, utilize capacity effect to the output of front stage circuits as a result signal take a sample, when this keeps pattern, the result who takes a sample is outputed to late-class circuit again, to carry out follow-up processing (as the analog digital conversion).
Please continue to consult Figure 1B, deserve passive echo elimination device of the present invention when being in the mode of operation of this signal sampling mode, be coupled to input, VICM, and the VOCM (being the common-mode voltage of input and output) of state amplifier 37 from the reception signal of the output (the 6th, the 5th node 906,905) of passive type echo cancellation circuit coupling 42 respectively by the capacitor C (361,362) of commutation circuit 36.This receives signal and be sent to the signal processing that receiving terminal 33 carries out analog-to-digital by VOP and VON again after state amplifier 37 is adjusted gain.
Shown in Fig. 1 C, deserve passive echo elimination device of the present invention when being in this signal and keeping the mode of operation of pattern, be open circuit (open circuit) between this two capacitor C (361,362) of output of passive type echo cancellation circuit coupling 42 (the 6th, the 5th node 906,905) and sample-and-hold circuit 36, VICM and VOCM also are with the input of state amplifier 37 and open circuit, the output of state amplifier 37 then is coupled to its input by electric capacity 363,364, reaches the purpose that signal is kept.
Because the framework and the running of sample-and-hold circuit are well known to those skilled in the art, so do not give unnecessary details at this.In first embodiment shown in Figure 1A to a C, be the first order circuit that is used as the analog-to-digital conversion circuit (DAC) of receiving terminal by sample-and-hold circuit 36, with sampling mode that receives signal and the switch operating of keeping pattern; Yet, also can select to use other prior art to substitute, such as, but be not limited to MDAC1 circuit etc.
See also Fig. 2 A, Fig. 2 B and Fig. 2 C.Wherein, Fig. 2 A is the circuit diagram of second embodiment of passive echo elimination device of the present invention; Fig. 2 B is the circuit diagram of passive echo elimination device under signal sampling mode state shown in Fig. 2 A; Fig. 2 C then keeps circuit diagram under the mode state for passive echo elimination device shown in Fig. 2 A in signal.In this second embodiment, because transmission end 31, line interface 32, receiving terminal 33, line drive 35, and thin portion formation, mode of operation and the realization effect of pressure reduction circuit 41 (that is offsetting signal generating circuit), be similar to first embodiment shown in Figure 1A to Fig. 1 C substantially, so repeat no more.
In second embodiment of the passive echo elimination device of the present invention shown in Fig. 2 A to Fig. 2 C, this passive type echo cancellation circuit coupling 52 also includes: some electric capacity 521～524 (called after first to fourth electric capacity in regular turn) and suitable circuit connect.One input of first electric capacity 521 is coupled in the 3rd node 903 between pressure reduction circuit 41 and the line interface 32.One input of second electric capacity 522 is coupled in the first node 901 between pressure reduction circuit 41 and the transmission end 31.One input of the 3rd electric capacity 523 is coupled in the 4th node 904 between pressure reduction circuit 41 and the transmission end 31.One input of the 4th electric capacity 524 is coupled in the Section Point 902 between pressure reduction circuit 41 and the line interface 32.
Transmit the influence that signal Rx is received in signal Tx butt joint in order to remove effectively, be positioned at the signal 2Tx at pressure reduction circuit 41 two ends and Tx+Rx as mentioned above, input in the echo cancellation circuit coupling 42 with phase inversion system, and transmit signal components in proportions poor (being twice) therebetween in order to compensate, then be made as C together as if capacitance with first electric capacity 521 and the 4th electric capacity 524, the capacitance of second electric capacity 522 and the 3rd electric capacity 523 promptly should just be the relation of twice with being made as 0.5C.Then, first electric capacity 521 is connected with the other end of second electric capacity 522 and constitutes one first output (the 5th node 905), and the 3rd electric capacity 523 also is connected with the other end of the 4th electric capacity 524 and constitute one second output (the 6th node 906).And this first and second output (the 5th, the 6th node 905,906) is coupled to this receiving terminal 33 by sample-and-hold circuit 46.
Through planting circuit design thus, the signal value that we just can calculate pressure reduction circuit 41 two ends easily by the dividing potential drop theory is through after the processing of echo cancellation circuit coupling 52, for the influence of the charge value at node 906 places as shown in the formula (3):
-2Tx×0.5C+(Tx+Rx)×C (3)
＝Rx·C
In like manner, its for the influence of the charge value at the 5th node 905 places then as shown in the formula (4):
2Tx×0.5C-(Tx+Rx)×C (4)
＝-Rx·C
Can get by formula (3) and formula (4), in the passive echo elimination device of second embodiment of the invention, the signal value that this first and second output (the 5th, the 6th node 905,906) is located, also general with first embodiment, (Rx), contained echo interference is eliminated by passive echo elimination device of the present invention in the former as can be known reception signal to receive signal Rx in proportion to.Because the passive type echo cancellation circuit coupling 52 of present embodiment only uses passive type assembly such as electric capacity and simple circuit design, so, compared to the prior art of aforementioned use active element, the passive echo elimination device of present embodiment can have more that circuit design is simple relatively, cost is relatively low and the advantage person of power saving etc. comparatively.
Please note, present embodiment also can be with the electric capacity in the sample-and-hold circuit 46 363,364 and/or first, two, three, four electric capacity 521-524 are designed to tunable capacitor (variable capacitor), decide the voltage gain value of being desired by the ratio of adjusting capacitance, though because the event that echo cancellation circuit coupling 52 realizes with the passive type assembly fully, its voltage gain value can only be the value less than 1, but as previously mentioned, for advanced technology, the needs that amplify of the signal that receives into of no-trump, the amplitude of signal must be dwindled (promptly using voltage gain value) on the contrary, could cooperate the operation of subsequent conditioning circuit less than 1.Therefore, the passive type echo cancellation circuit coupling 52 in the present embodiment is particularly suitable for being used in the middle of the advanced technology.
Through the output signal that processing produced of echo cancellation circuit coupling 52, promptly only include the composition that receives signal Rx, and be transferred into the first order circuit of receiving terminal 33 again, in present embodiment sample-and-hold circuit 46.Though the sample-and-hold circuit 46 in the present embodiment is in order to cooperate the framework of the echo cancellation circuit coupling that is made of electric capacity 521-524, sample-and-hold circuit 36 among its circuit framework and first embodiment has partly comes in and goes out, but because being those skilled in the art institutes, the realization of sample-and-hold circuit and principle extensively understand, so its detailed architecture and operating principle will no longer be given unnecessary details at this.
See also Fig. 3, it is the circuit diagram of the 3rd embodiment of passive echo elimination device of the present invention.In this 3rd embodiment, because most assembly is for example: line interface 32, receiving terminal 33, sample-and-hold circuit 36, and thin portion formation, mode of operation and the realization effect of echo cancellation circuit coupling 42a etc., be similar to first embodiment shown in Figure 1A substantially, therefore, identical assembly will directly give identical title and numbering and repeat no more its formation.Relatively, the following description will only not exist together with previous embodiment at this 3rd embodiment and will be described.
As shown in Figure 3, in the 3rd embodiment of passive echo elimination device of the present invention, set digital analog converter (DAC) is to realize with a duplicate circuit 314 (Replica) of a current type digital analog converter 313 (Current DAC) and current type digital analog converter 313 in the 31a of this transmission end.In present embodiment, duplicate circuit 314 comes down to constitute one in the passive echo elimination device of the present invention and offsets signal generating circuit, just can be used to produce a counteracting signal person (promptly duplicating signal) of the composition that only includes the transmission signal Tx that is produced by current type digital analog converter 313.In addition, the resistance value R1 of first to fourth resistance 421a～424a of the passive type echo cancellation circuit coupling 42a of present embodiment is then all identical.
In this 3rd embodiment, include a plurality of converting unit 3131～313n in the current type digital analog converter 313.And each converting unit 3131～313n can provide the digital signal (D for institute's desire conversion respectively
1... D
N) in one (Bit) carry out the translation function that digital revolving die is intended (D/A), for example, if when the digital signal of required conversion is 8, n=8 then.Two analog signal output+O1 of each converting unit 3131～313n～+ On ,-O1～-On comes together in second, third node 902,903 respectively.From the digital signal of transmission end 31, through after this current type digital analog converter 313 converts analog signal to, be sent to long-range another network equipment via this line interface 32 and the twisted-pair feeder 34 that connected thereof.As for, this 902,903 of second, third node is to be respectively coupled to the 4th resistance 424a among the passive type echo cancellation circuit coupling 42a of the present invention and the input of the first resistance 421a.
As previously mentioned because the full duplex characteristic of Gigabit Ethernet, make this second, third received analog signal in node 902,903 positions be respectively have echo+Rx+Tx and-the Rx-Tx signal.Relatively, 901,904 of the first, the 4th nodes only have from this duplicate circuit 314+Tx and-the Tx signal.Apparently, first output (the 5th node 905) of the passive type echo cancellation circuit coupling 42a in this 3rd embodiment can be repealed by implication and obtain-output of Rx signal because of the 3rd node 903 contained-Rx-Tx signals and first node 901 contained+Tx signals; On the other hand, its second output (the 6th node 906) is also repealed by implication and is obtained+output of Rx signal because of Section Point 902 contained+Rx+Tx signals and the 4th node 904 contained-Tx signals.Thus, just can reach the effect of only using resistance passive component and proper circuit connection just can eliminate the echo interference that receives in the signal.
See also Fig. 4, it is the circuit diagram of the 4th embodiment of passive echo elimination device of the present invention.This 4th embodiment is similar to aforementioned the 3rd embodiment content shown in Figure 3 substantially, its both difference only is: in fourth embodiment of the invention shown in Figure 4, this passive echo elimination device is to use some electric capacity 521a～524a (called after first to fourth electric capacity in regular turn) shown in Fig. 2 A and suitable circuit to connect and realizes.Wherein, the capacitance C of each electric capacity 521a～524a is identical.And the input of the first electric capacity 521a is connected in the 3rd node 903, just is connected between the signal output end and line interface 32 of current type digital analog converter 313; The input of the second electric capacity 522a be connected in first node 901 just be connected to the one output+O1 of this duplicate circuit 314～+ On; The input of the 3rd electric capacity 523a be connected in the 4th node 904 just be connected to another output-O1 of duplicate circuit 314～-On; The input of the 4th electric capacity 524a is connected in Section Point 902, just is connected between the signal output end and line interface 32 of current type digital analog converter 313.Apparently, first output (the 5th node 905) of the passive type echo cancellation circuit coupling 52a in this 4th embodiment can be repealed by implication and obtain-output of Rx signal because of the 3rd node 903 contained-Rx-Tx signals and first node 901 contained+Tx signals; On the other hand, its second output (the 6th node 906) is also repealed by implication and is obtained+output of Rx signal because of Section Point 902 contained+Rx+Tx signals and the 4th node 904 contained-Tx signals.Thus, just can reach the effect of only using the electric capacity passive component to be connected just to eliminate the echo that receives in the signal to disturb with proper circuit.
By each above-mentioned embodiment content as can be known, passive echo elimination device of the present invention only need use some passive components and cooperate proper circuit to connect, and just can reach the function of eliminating echo.Therefore, the prior art of using active element such as operational amplifiers or transistor to carry out echo cancellation compared to those, advantage such as passive echo elimination device of the present invention obviously has more power saving, circuit design is simpler and the assembly cost is cheaper.And have on the network equipment (for example network switch of many PORT COM) of many PORT COM quantity at some, power consumption and cost that passive echo elimination device of the present invention can be saved are especially remarkable.Though the prior art of carrying out echo cancellation with active element can provide butt joint to receive the function that signal provides the active gain.Yet, because in the semiconductor technology of integrated circuit, its operating voltage of integrated circuit that is manufactured by more advanced semiconductor technology (for example 0.18 micron or following) is lower, also more needs not exceed 1 voltage gain.In other words, passive echo elimination device of the present invention more is applicable to than prior art on the contrary and is implemented in on the integrated circuit that more sophisticated semiconductor technology manufactures.
In sum; though the present invention discloses as above with a preferred embodiment; right its is not in order to limit the present invention; those skilled in the art can be used for a variety of modifications and variations under the premise without departing from the spirit and scope of the present invention, so protection scope of the present invention is as the criterion with claim of the present invention.
Claims (17)
1. a passive echo elimination device is applicable to that in the full duplex communication system, this full duplex communication system comprises a transmission end, in order to transmitting signal to a line interface, and a receiving terminal, receives signal in order to this line interface certainly; This passive echo elimination device includes:
One passive type echo cancellation circuit coupling, it is made up of some passive components and is serially connected with between line interface and the receiving terminal and between transmission end and receiving terminal, and this passive type echo cancellation circuit coupling fechtable is from the signal of transmission end and use payment from the echo signal in this reception signal of line interface.
2. passive echo elimination device as claimed in claim 1, wherein, these some passive components are some resistance.
3. passive echo elimination device as claimed in claim 1, wherein, these some passive components are some electric capacity.
4. passive echo elimination device as claimed in claim 1, wherein, also include a pressure reduction circuit, be serially connected with between transmission end and the line interface, the magnitude of voltage of transmission signal that this pressure reduction circuit connects the side of this transmission end connects the prearranged multiple of transmission signal voltage value of the side of this line interface for this pressure reduction circuit, and this prearranged multiple is greater than 1.
5. passive echo elimination device as claimed in claim 4, wherein, this pressure reduction circuit is made of resistance.
6. passive echo elimination device as claimed in claim 5, wherein, this passive type echo cancellation circuit coupling also includes:
One first resistance, one end are coupled on one the 3rd node between pressure reduction circuit and the line interface;
One second resistance, one end are coupled on the first node between pressure reduction circuit and the transmission end;
One the 3rd resistance, one end are coupled on one the 4th node between pressure reduction circuit and the transmission end; And,
One the 4th resistance, one end are coupled on the Section Point between pressure reduction circuit and the line interface;
Wherein, the resistance value of this second resistance is identical with the 3rd resistance, and the resistance value of first resistance is identical with the 4th resistance, and the ratio of the resistance value of the resistance value of second resistance and first resistance equals this prearranged multiple;
Wherein, first resistance is connected with the other end of second resistance and constitutes one first output, and the 3rd resistance also is connected with the other end of the 4th resistance and constitute one second output, and this first and second output is coupled in this receiving terminal.
7. passive echo elimination device as claimed in claim 5, wherein, this passive type echo cancellation circuit coupling also includes:
One first electric capacity, one end are coupled on one the 3rd node between pressure reduction circuit and the line interface;
One second electric capacity, one end are coupled on the first node between pressure reduction circuit and the transmission end;
One the 3rd electric capacity, one end are coupled on one the 4th node between pressure reduction circuit and the transmission end; And,
One the 4th electric capacity, one end are coupled on the Section Point between pressure reduction circuit and the line interface;
Wherein, the capacitance of this second electric capacity is identical with the 3rd electric capacity, and the capacitance of first electric capacity is identical with the 4th electric capacity, and the ratio of the capacitance of the capacitance of first electric capacity and second electric capacity equals this prearranged multiple;
Wherein, first electric capacity is connected with the other end of second electric capacity and constitutes one first output, and the 3rd electric capacity also is connected with the other end of the 4th electric capacity and constitute one second output, and this first and second output is coupled in this receiving terminal.
8. passive echo elimination device as claimed in claim 1 wherein, also includes a duplicate circuit of a current type digital analog converter and this current type digital analog converter; This current type digital analog converter is positioned at the transmission end and supplies output one analog signal to this line interface; Wherein, this passive type echo cancellation circuit coupling also includes:
One first resistance, one end are coupled on the node between current type digital analog converter and the line interface;
One second resistance, one end are coupled in the output of duplicate circuit;
One the 3rd resistance, one end are coupled in another output of duplicate circuit; And,
One the 4th resistance, one end are coupled on another node between current type digital analog converter and the line interface;
Wherein, this first, second, third, and the resistance value of the 4th resistance all identical;
Wherein, first resistance is connected with the other end of second resistance and constitutes one first output, and the 3rd resistance also is connected with the other end of the 4th resistance and constitute one second output, and this first and second output is coupled in this receiving terminal.
9. passive echo elimination device as claimed in claim 1 wherein, also includes a duplicate circuit of a current type digital analog converter and this current type digital analog converter; This current type digital analog converter is positioned at the transmission end and supplies output one analog signal to this line interface; Wherein, this passive type echo cancellation circuit coupling also includes:
One first electric capacity, one end are coupled on the node between current type digital analog converter and the line interface;
One second electric capacity, one end are coupled in the output of duplicate circuit;
One the 3rd electric capacity, one end are coupled in another output of duplicate circuit; And,
One the 4th electric capacity, one end are coupled on another node between current type digital analog converter and the line interface;
Wherein, this first, second, third, and the capacitance of the 4th electric capacity all identical;
Wherein, first electric capacity is connected with the other end of second electric capacity and constitutes one first output, and the 3rd electric capacity also is connected with the other end of the 4th electric capacity and constitute one second output, and this first and second output is coupled in this receiving terminal.
10. a passive echo elimination device is applicable in the communication system, this communication system comprise one in order to produce a transmission end of transmitting signal, a line interface, and one in order to accept a receiving terminal that receives signal; This passive echo elimination device includes:
One offsets signal generating circuit, in order to produce a counteracting signal that transmits signal corresponding to this; And
One passive type echo cancellation circuit coupling, it only includes some passive components, and is serially connected with between line interface and the receiving terminal and is to be connected in this counteracting signal generating circuit; This passive type echo cancellation circuit coupling captures this counteracting signal and uses a contained echo signal in payment this reception signal from line interface, to produce an output signal that only includes the signal feature of this reception signal.
11. passive echo elimination device as claimed in claim 10, wherein, this passive type echo cancellation circuit coupling also includes:
One first passive component, one end are coupled on the node between transmission end and the line interface;
One second passive component, one end are coupled in the output of offsetting signal generating circuit;
One the 3rd passive component, one end are coupled in another output of offsetting signal generating circuit; And,
One the 4th passive component, one end are coupled on another node between transmission end and the line interface;
Wherein, first passive component is connected with the other end of second passive component and constitutes one first output, and the 3rd passive component also is connected with the other end of the 4th passive component and constitute one second output, and this first and second output is coupled in this receiving terminal.
12. passive echo elimination device as claimed in claim 11, wherein, this first to fourth passive component be following one of them: resistance and electric capacity.
13. a signal receiving/transmission method, it includes:
One transmitting-receiving path is provided;
On this transmitting-receiving path, receives signal and transmit signal, to such an extent as to produce an echo signal that forms by the overlapping of this reception signal and this transmission signal;
The one counteracting signal that includes the signal feature of this transmission signal is provided; And
Use an echo cancellation circuit coupling that only includes the passive type assembly, eliminate this transmission signal in this echo signal, to produce an output signal that includes the signal feature of this reception signal according to this counteracting signal.
14. signal receiving/transmission method as claimed in claim 13, wherein this transmission signal is produced by a gleam of driver.
15. signal receiving/transmission method as claimed in claim 13, wherein this transmission signal is produced by a current type digital analog converter.
16. signal receiving/transmission method as claimed in claim 13, wherein this echo cancellation circuit coupling only includes a plurality of resistance.
17. signal receiving/transmission method as claimed in claim 13, wherein this echo cancellation circuit coupling only includes a plurality of electric capacity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007100862130A CN101262251A (en) | 2007-03-09 | 2007-03-09 | Passive echo elimination device and its signal receiving/transmission method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007100862130A CN101262251A (en) | 2007-03-09 | 2007-03-09 | Passive echo elimination device and its signal receiving/transmission method |
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| Publication Number | Publication Date |
|---|---|
| CN101262251A true CN101262251A (en) | 2008-09-10 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2007100862130A Pending CN101262251A (en) | 2007-03-09 | 2007-03-09 | Passive echo elimination device and its signal receiving/transmission method |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102647205A (en) * | 2011-02-22 | 2012-08-22 | 中国石油集团长城钻探工程有限公司 | Communication echo elimination device and method |
| CN103546197A (en) * | 2012-07-13 | 2014-01-29 | 瑞昱半导体股份有限公司 | Method for setting transceiving system integrating mixer circuit and digital subscriber loop |
| CN112311419A (en) * | 2019-07-29 | 2021-02-02 | 瑞昱半导体股份有限公司 | Communication device capable of eliminating echo |
| CN113972930A (en) * | 2020-07-23 | 2022-01-25 | 瑞昱半导体股份有限公司 | Echo estimation system and echo estimation method |
-
2007
- 2007-03-09 CN CNA2007100862130A patent/CN101262251A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102647205A (en) * | 2011-02-22 | 2012-08-22 | 中国石油集团长城钻探工程有限公司 | Communication echo elimination device and method |
| CN103546197A (en) * | 2012-07-13 | 2014-01-29 | 瑞昱半导体股份有限公司 | Method for setting transceiving system integrating mixer circuit and digital subscriber loop |
| CN103546197B (en) * | 2012-07-13 | 2015-07-29 | 瑞昱半导体股份有限公司 | For receive-transmit system and the establishing method thereof of digital user loop |
| CN112311419A (en) * | 2019-07-29 | 2021-02-02 | 瑞昱半导体股份有限公司 | Communication device capable of eliminating echo |
| CN112311419B (en) * | 2019-07-29 | 2021-10-19 | 瑞昱半导体股份有限公司 | Communication device capable of eliminating echo |
| CN113972930A (en) * | 2020-07-23 | 2022-01-25 | 瑞昱半导体股份有限公司 | Echo estimation system and echo estimation method |
| CN113972930B (en) * | 2020-07-23 | 2024-02-13 | 瑞昱半导体股份有限公司 | Echo estimation system and echo estimation method |
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Application publication date: 20080910 |