CN221240421U - Communication interface circuit for eliminating echo by transformer and building intercom device - Google Patents
Communication interface circuit for eliminating echo by transformer and building intercom device Download PDFInfo
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- CN221240421U CN221240421U CN202322862596.3U CN202322862596U CN221240421U CN 221240421 U CN221240421 U CN 221240421U CN 202322862596 U CN202322862596 U CN 202322862596U CN 221240421 U CN221240421 U CN 221240421U
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- 238000004804 winding Methods 0.000 claims description 51
- 239000003990 capacitor Substances 0.000 claims description 30
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Abstract
The utility model discloses a communication interface circuit for eliminating echo by using a transformer and a building intercom device, wherein the communication interface circuit for eliminating echo by using the transformer comprises a first driving unit and an echo elimination unit, wherein the input end of the first driving unit is connected with the transmitting end of a communication interface, and the first driving unit is used for amplifying and driving signals transmitted by the transmitting end; the first end of the echo cancellation unit is connected with the output end of the first driving unit, the second end of the echo cancellation unit is connected to the transmission medium, the echo cancellation unit adopts a transformer to cancel the signal sent by the sending end, and the opposite end signal transmitted by the transmission medium is sent to the receiving end of the communication interface; therefore, the transformer is directly adopted for echo cancellation, so that the circuit structure is relatively simple and the cancellation effect is good.
Description
Technical Field
The utility model relates to the technical field of full duplex network data communication, in particular to a communication interface circuit for eliminating echo by adopting a transformer and a building intercom device.
Background
In the related art, full duplex network communication generally uses 2-to-4 wire cables for signal transmission and reception. However, since the 2-wire cable needs to be responsible for transmitting and receiving ethernet signals at the same time, signals on the transmission medium and the interface thereof are mixed signals of the transmitting signals and the receiving signals, so that full duplex transmission of ethernet signals is to be realized through the 2-wire cable, the receiving end of the communication interface needs to only receive signals transmitted from the opposite end, that is, signals transmitted from the transmitting end of the communication interface need to be eliminated; the existing echo cancellation circuit generally adopts an operational amplifier to cancel, and the circuit adopting the mode has poor cancellation effect on high-frequency signals.
Disclosure of utility model
The present utility model aims to solve at least to some extent one of the technical problems in the above-described technology. Therefore, the utility model aims to provide a communication interface circuit for eliminating echo by adopting a transformer, and echo elimination is carried out by directly adopting the transformer, so that the circuit structure is relatively simple and the elimination effect is good.
In order to achieve the above purpose, the communication interface circuit for eliminating echo by using a transformer provided by the utility model comprises a first driving unit, wherein the input end of the first driving unit is connected with the transmitting end of the communication interface, the first driving unit is used for amplifying and driving a signal transmitted by the transmitting end, and the output impedance is extremely low and can be ignored; the first end of the echo elimination unit is connected with the output end of the first driving unit, the second end of the echo elimination unit is connected to a transmission medium, the echo elimination unit eliminates signals sent by the sending end by adopting a transformer, and sends opposite-end signals transmitted by the transmission medium to the receiving end of the communication interface.
The communication interface circuit for eliminating echo by adopting the transformer comprises a first driving unit and an echo elimination unit, wherein the input end of the first driving unit is connected with the transmitting end of the communication interface, and the first driving unit is used for amplifying and driving signals transmitted by the transmitting end; the first end of the echo cancellation unit is connected with the output end of the first driving unit through Zs, the second end of the echo cancellation unit is connected to the transmission medium, the echo cancellation unit adopts a transformer to cancel signals sent by the sending end, and opposite-end signals transmitted by the transmission medium are sent to the receiving end of the communication interface; therefore, the transformer is directly adopted for echo cancellation, so that the circuit structure is relatively simple and the cancellation effect is good.
In addition, the communication interface circuit for eliminating echo by using the transformer according to the present utility model may further have the following additional technical features:
optionally, the communication interface circuit for eliminating echo by adopting the transformer further comprises: the input end of the second driving unit is connected with the third end of the echo cancellation unit, the output end of the second driving unit is connected to the receiving end of the communication interface, and the second driving unit is used for amplifying the opposite-end signal so that the receiving end of the communication interface receives the signal sent by the opposite end.
Optionally, the echo cancellation unit comprises: a transformer, the primary winding of the transformer comprising a first winding and a second winding, the secondary winding comprising a third winding, the third winding being connected to a transmission medium; a first resistor having one end connected to an output end of the first driving unit and having a first node; a second resistor having one end connected to the other end of the first resistor and having a second node, the other end of the second resistor being connected to the second winding; one end of the third resistor is connected to the first node, and the other end of the third resistor is connected with the first winding; and one end of the first capacitor is connected between the first winding and the second winding, and the other end of the first capacitor is grounded.
Optionally, the first driving unit includes a first driving amplifier, an input terminal of the first driving amplifier is connected to the transmitting terminal of the communication interface, and an output terminal of the first driving amplifier is connected to the first node.
Optionally, the first driving unit further includes: one end of the fourth resistor is connected with the negative input end of the first drive amplifier, and the other end of the fourth resistor is connected with the output end of the first drive amplifier; and one end of the second capacitor is connected to the transmitting end of the communication interface, and the other end of the second capacitor is connected to the positive input end of the first operational amplifier.
Optionally, the second driving unit includes a second driving amplifier, an input terminal of the second driving amplifier is connected to the second node, and an output terminal of the second driving amplifier is connected to a receiving terminal of the communication interface.
Optionally, the second driving unit further includes: one end of the fifth resistor is connected to the output end of the second driving amplifier, and the other end of the fifth resistor is connected with the negative input end of the second driving amplifier; one end of the sixth resistor is connected with the other end of the fifth resistor; one end of the third capacitor is connected with the receiving end of the communication interface, and the other end of the third capacitor is connected with one end of the fifth resistor; and one end of the fourth capacitor is connected with the other end of the sixth resistor, and the other end of the fourth capacitor is grounded.
Optionally, the number of turns of the first winding and the number of turns of the second winding are equal.
Optionally, the number of turns of the third winding is the sum of the number of turns of the first winding and the number of turns of the second winding.
To achieve the above object, a second aspect of the present utility model provides a building intercom device including a communication interface circuit for eliminating echo by using a transformer as described above.
According to the building intercom device disclosed by the embodiment of the utility model, the echo cancellation is performed by directly adopting the transformer, so that the circuit structure is relatively simple and the cancellation effect is good.
Drawings
FIG. 1 is a block schematic diagram of a communication interface circuit employing a transformer to cancel echo in accordance with an embodiment of the present utility model;
FIG. 2 is a circuit schematic of a communication interface circuit employing a transformer to cancel echo in accordance with one embodiment of the present utility model;
fig. 3 is a circuit schematic of a communication interface circuit employing a transformer to cancel echo in accordance with one embodiment of the present utility model.
Detailed Description
Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present utility model and should not be construed as limiting the utility model.
In order that the above-described aspects may be better understood, exemplary embodiments of the present utility model will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present utility model are shown in the drawings, it should be understood that the present utility model may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the utility model to those skilled in the art.
In order to better understand the above technical solutions, the following detailed description will refer to the accompanying drawings and specific embodiments.
Referring to fig. 1-2, a communication interface circuit for echo cancellation using a transformer according to an embodiment of the present utility model includes a first driving unit 10 and an echo cancellation unit 20.
The input end of the first driving unit 10 is connected to the transmitting end of the communication interface, and the first driving unit 10 is configured to amplify and drive the ethernet TX signal transmitted by the transmitting end.
In addition, the first driving unit 10 may output an output impedance approaching zero in addition to driving the signal transmitted from the transmitting end.
As a specific embodiment, as shown in fig. 3, the first driving unit 10 includes a first driving amplifier U1, an input terminal of the first driving amplifier U1 is connected to a transmitting terminal of the communication interface, and an output terminal of the first driving amplifier U1 is connected to the first node.
As a specific embodiment, as shown in fig. 3, the first driving unit 10 further includes a fourth resistor R4 and a second capacitor C2; one end of a fourth resistor R4 is connected with the negative input end of the first driving amplifier U1, and the other end of the fourth resistor R4 is connected with the output end of the first driving amplifier U1; one end of the second capacitor C2 is connected to the transmitting end of the communication interface, and the other end of the second capacitor C2 is connected to the positive input end of the first driving amplifier U1.
The first end of the echo cancellation unit 20 is connected to the output end of the first driving unit 10, the second end of the echo cancellation unit 20 is connected to the transmission medium, the echo cancellation unit 20 uses a transformer to cancel the signal sent by the sending end, and sends the opposite end signal transmitted by the transmission medium to the receiving end of the communication interface.
That is, the signal is obtained by using different windings of the transformer, that is, the self signal sent by the sending end can be eliminated, and the signal from the opposite end can be received.
It should be noted that, the transmission medium may be twisted pair or parallel cable, which is not particularly limited in the present utility model.
As a specific embodiment, as shown in fig. 3, the echo cancellation unit 20 includes a transformer T1, a first resistor R1, a second resistor R2, a third resistor R3, and a first capacitor C1; wherein the primary winding of the transformer T1 comprises a first winding N1 and a second winding N2, the secondary winding comprises a third winding N3, and the third winding N3 is connected to a transmission medium; one end of the first resistor R1 is connected to the output terminal of the first driving unit 10 and has a first node; one end of the second resistor R2 is connected to the other end of the first resistor R1, the second resistor R2 is provided with a second node, and the other end of the second resistor R2 is connected to the second winding N2; one end of a third resistor R3 is connected to the first node, and the other end of the third resistor R3 is connected with the first winding N1; one end of the first capacitor C1 is connected between the first winding N1 and the second winding N2, and the other end of the first capacitor C1 is grounded; the first capacitor C1 is an ac blocking capacitor.
It should be noted that the number of turns of the first winding N1 and the number of turns of the second winding N2 of the transformer T1 are equal; the number of turns of the third winding is the sum of the number of turns of the first winding and the number of turns of the second winding.
As one example, the turns ratio of the first winding N1, the second winding N2, and the third winding N3 may be set to N1: n2: n3=1:1:2.
As shown in fig. 2, in the transmitting-side signal clearing stage, if the transmission medium has no reflected wave, the load impedance Z T is approximately equal to the characteristic impedance Zc, and the load impedance Z is based on the impedance transformationSetting the impedance Z S＝ZL , of the third resistor R3I.e.Since the V2 of the first winding N1 and the V3 node of the second winding N2 are non-homonymous ends, theWhen R1 and R2 are far larger than Z S or Z L, the values of R1 and R2 need to satisfyI.e.Will beSubstituting the above equation yields: I.e. Finally obtainThat is, if it meetsThe own signal transmitted by the transmitting end can be eliminated at the second node through the transformer T1.
Furthermore, in the phase of receiving the opposite-end signal, the output impedance of the first driving amplifier is extremely low and can be ignored compared with Zs, so that the voltage from the opposite-end transmitting signal received at the second node(V3' is the signal component from the opposite end)The opposite end signal after the self signal sent by the sending end is cleared is obtained at the second node, and the voltage signal V5 is obtained through amplification of a proper multiple by the second driving unit 30, so as to be sent to the receiving end of the communication interface.
As an embodiment, the communication interface circuit for eliminating the echo by using the transformer further comprises a second driving unit 30, an input end of the second driving unit 30 is connected to the third end of the echo eliminating unit 20, an output end of the second driving unit 30 is connected to a receiving end of the communication interface, that is, receives the ethernet RX signal, and the second driving unit 30 is configured to amplify the opposite end signal so that the receiving end of the communication interface receives the opposite end signal.
As a specific embodiment, as shown in fig. 3, the second driving unit 30 includes a second driving amplifier U2, an input terminal of the second driving amplifier U2 is connected to the second node, and an output terminal of the second driving amplifier U2 is connected to a receiving terminal of the communication interface.
It should be noted that the polarity of the receiving end R X of the communication interface is adaptive, so that the receiving end R X can be connected to the positive end or the negative end.
As a specific embodiment, as shown in fig. 3, the second driving unit 30 further includes a fifth resistor R5, a sixth resistor R6, a third capacitor C3, and a fourth capacitor C4; one end of a fifth resistor R5 is connected to the output end of the second driving amplifier U2, and the other end of the fifth resistor R5 is connected with the negative input end of the second driving amplifier U2; one end of the sixth resistor R6 is connected with the other end of the fifth resistor R5; one end of the third capacitor C3 is connected with the receiving end of the communication interface, and the other end of the third capacitor C3 is connected with one end of the fifth resistor R5; one end of the fourth capacitor C4 is connected with the other end of the sixth resistor R6, and the other end of the fourth capacitor C4 is grounded.
In summary, the communication interface circuit for eliminating echo by using the transformer according to the present utility model includes a first driving unit and an echo eliminating unit, wherein an input end of the first driving unit is connected with a transmitting end of the communication interface, and the first driving unit is used for amplifying and driving a signal transmitted by the transmitting end; the first end of the echo cancellation unit is connected with the output end of the first driving unit, the second end of the echo cancellation unit is connected to the transmission medium, the echo cancellation unit adopts a transformer to cancel the signal sent by the sending end, and the opposite end signal transmitted by the transmission medium is sent to the receiving end of the communication interface; therefore, the transformer is directly adopted for echo cancellation, so that the circuit structure is relatively simple and the cancellation effect is good.
In addition, the embodiment of the utility model also provides a building intercom device which comprises the communication interface circuit for eliminating echo by adopting the transformer.
According to the building intercom device disclosed by the embodiment of the utility model, the echo cancellation is performed by directly adopting the transformer, so that the circuit structure is relatively simple and the cancellation effect is good.
In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present utility model, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
In the present utility model, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.
In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present utility model. In this specification, schematic representations of the above terms should not be understood as necessarily being directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Further, one skilled in the art can engage and combine the different embodiments or examples described in this specification.
While embodiments of the present utility model have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the utility model, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the utility model.
Claims (10)
1. A communication interface circuit for echo cancellation using a transformer, comprising:
the input end of the first driving unit is connected with the transmitting end of the communication interface, and the first driving unit is used for amplifying and driving signals transmitted by the transmitting end;
The first end of the echo elimination unit is connected with the output end of the first driving unit, the second end of the echo elimination unit is connected to a transmission medium, the echo elimination unit eliminates signals sent by the sending end by adopting a transformer, and sends opposite-end signals transmitted by the transmission medium to the receiving end of the communication interface.
2. The communication interface circuit for echo cancellation using a transformer of claim 1, further comprising:
The input end of the second driving unit is connected with the third end of the echo cancellation unit, the output end of the second driving unit is connected to the receiving end of the communication interface, and the second driving unit is used for amplifying the opposite-end signal so that the receiving end of the communication interface receives the signal sent by the opposite end.
3. The communication interface circuit for canceling echo using a transformer according to claim 2, wherein the echo canceling unit includes:
A transformer, the primary winding of the transformer comprising a first winding and a second winding, the secondary winding comprising a third winding, the third winding being connected to a transmission medium;
a first resistor having one end connected to an output end of the first driving unit and having a first node;
a second resistor having one end connected to the other end of the first resistor and having a second node, the other end of the second resistor being connected to the second winding;
one end of the third resistor is connected to the first node, and the other end of the third resistor is connected with the first winding;
And one end of the first capacitor is connected between the first winding and the second winding, and the other end of the first capacitor is grounded.
4. A communication interface circuit for echo cancellation using a transformer as claimed in claim 3, where the first drive unit includes a first drive amplifier, an input of the first drive amplifier being connected to a transmit terminal of the communication interface, an output of the first drive amplifier being connected to the first node.
5. The communication interface circuit for echo cancellation using a transformer of claim 4, wherein the first drive unit further comprises:
one end of the fourth resistor is connected with the negative input end of the first drive amplifier, and the other end of the fourth resistor is connected with the output end of the first drive amplifier;
And one end of the second capacitor is connected to the transmitting end of the communication interface, and the other end of the second capacitor is connected to the positive input end of the first driving amplifier.
6. A communication interface circuit for echo cancellation using a transformer as claimed in claim 3, where the second drive unit includes a second drive amplifier, an input of the second drive amplifier being connected to the second node, an output of the second drive amplifier being connected to a receiving end of the communication interface.
7. The communication interface circuit for echo cancellation using a transformer according to claim 6, wherein the second drive unit further comprises:
One end of the fifth resistor is connected to the output end of the second drive amplifier, and the other end of the fifth resistor is connected with the negative input end of the second drive amplifier;
one end of the sixth resistor is connected with the other end of the fifth resistor;
One end of the third capacitor is connected with the receiving end of the communication interface, and the other end of the third capacitor is connected with one end of the fifth resistor;
and one end of the fourth capacitor is connected with the other end of the sixth resistor, and the other end of the fourth capacitor is grounded.
8. A communication interface circuit for echo cancellation using a transformer as claimed in claim 3, wherein the number of turns of the first winding and the number of turns of the second winding are equal.
9. The communication interface circuit for echo cancellation with a transformer of claim 8, wherein the number of turns of the third winding is the sum of the number of turns of the first winding and the number of turns of the second winding.
10. A building intercom device comprising a communications interface circuit as claimed in any of claims 1 to 9 employing a transformer to cancel echoes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322862596.3U CN221240421U (en) | 2023-10-24 | 2023-10-24 | Communication interface circuit for eliminating echo by transformer and building intercom device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322862596.3U CN221240421U (en) | 2023-10-24 | 2023-10-24 | Communication interface circuit for eliminating echo by transformer and building intercom device |
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| Publication Number | Publication Date |
|---|---|
| CN221240421U true CN221240421U (en) | 2024-06-28 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202322862596.3U Active CN221240421U (en) | 2023-10-24 | 2023-10-24 | Communication interface circuit for eliminating echo by transformer and building intercom device |
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| Country | Link |
|---|---|
| CN (1) | CN221240421U (en) |
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2023
- 2023-10-24 CN CN202322862596.3U patent/CN221240421U/en active Active
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