Signal transmitting and receiving circuit of digital subscriber line

Patent metadata

Field	Value
Publication number	US-9312912-B2
Application number	US-201414316539-A
Country	US
Kind code	B2
Filing date	Jun 26, 2014
Priority date	Oct 16, 2013
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

This invention discloses a signal transmitting and receiving circuit of a digital subscriber line used for transmitting an output signal to a telecommunication loop or receiving an input signal from the telecommunication loop. The signal transmitting and receiving circuit comprises a transformer, which is coupled to the telecommunication loop; a signal transmitting module, which is coupled to the transformer, for generating the output signal; a signal receiving module, which is coupled to the transformer, for processing the input signal; an echo cancelling circuit, comprising passive components and having two ends, one of which is coupled to the signal transmitting module and the transformer, the other is coupled to the signal receiving module and the transformer. The output signal is transmitted to the telecommunication loop via the electromagnetic coupling of the transformer, and the input signal is received by the signal receiving module by the electromagnetic coupling of the transformer.

First claim

What is claimed is:

1. A signal transmitting and receiving circuit of a digital subscriber line for transmitting an output signal to a telecommunication loop or receiving an input signal from the telecommunication loop, comprising:
a transformer comprising a first winding, a second winding, and a third winding, the first winding comprising a first coil and a second coil, the third winding coupled to the telecommunication loop and the first and the second coils comprising respectively a first polarity end and a second polarity end;
a first impedance unit comprising two ends coupled respectively to the first polarity end of the first coil and the first polarity end of the second coil;
a second impedance unit comprising two ends coupled respectively to the second polarity end of the first coil and the second polarity end of the second coil;
a signal transmitting module, coupled to the first winding, for generating the output signal; and
a signal receiving module, coupled to the second winding, for processing the input signal;
wherein, the first winding and the third winding transmit the output signal to the telecommunication loop by electromagnetic coupling, and the third winding and the second winding transmits the input signal to the signal receiving module by electromagnetic coupling.

2. The signal transmitting and receiving circuit of claim 1 , wherein the second winding comprises a third coil and a fourth coil, the third and the fourth coils comprise respectively a first polarity end and a second polarity end, and the signal receiving module comprises a receiving differential signal pair, whose positive end is coupled to the first polarity end of the third coil and negative end is coupled to the second polarity end of the fourth coil.

3. The signal transmitting and receiving circuit of claim 2 , wherein the signal transmitting module comprises a transmitting differential signal pair, whose positive end is coupled to the first polarity end of the first coil and negative end is coupled to the second polarity end of the second coil.

4. The signal transmitting and receiving circuit of claim 2 , further comprising:
a third impedance unit with one of its two ends coupled to the first polarity end of the first coil and the first polarity end of the fourth coil and the other end coupled to the second polarity end of the fourth coil; and
a fourth impedance unit with one of its two ends coupled to the second polarity end of the second coil and the second polarity end of the third coil and the other end coupled to the first polarity end of the third coil.

5. The signal transmitting and receiving circuit of claim 4 , wherein the third and the fourth impedance units are made of passive components.

6. The signal transmitting and receiving circuit of claim 5 , wherein the third and the fourth impedance units comprise at least a resistance component, a capacitance component and a switching component, and the switching component controls whether the equivalent impedance of the third and the fourth impedance units comprises the capacitance component or not.

7. The signal transmitting and receiving circuit of claim 6 , wherein when the signal transmitting and receiving circuit is applied to a very high speed digital subscriber line, the switching component controls the equivalent impedance of the third and the fourth impedance units to comprise only the resistance component.

8. The signal transmitting and receiving circuit of claim 1 , wherein a turns ratio of the third winding to the first winding is not equal to a turns ratio of the second winding to the third winding.

9. The signal transmitting and receiving circuit of claim 1 , wherein the digital subscriber line is an asymmetric digital subscriber line or a very high speed digital subscriber line.

10. A signal transmitting and receiving circuit of a digital subscriber line for transmitting an output signal to a telecommunication loop or receiving an input signal from the telecommunication loop, comprising:
a transformer coupled to the telecommunication loop;
a signal transmitting module, coupled to the transformer, for generating the output signal;
a signal receiving module, coupled to the transformer, for processing the input signal; and
an echo cancelling circuit made of passive components and comprising two ends, one of which is coupled to the signal transmitting module and the transformer, and the other is coupled to the signal receiving module and the transformer;
wherein, the output signal is transmitted to the telecommunication loop by electromagnetic coupling of the transformer, and the input signal is transmitted to the signal receiving module by electromagnetic coupling of the transformer, and the echo cancelling circuit comprises at least a resistance component, a capacitance component, and a switching component, and the switching component controls whether the equivalent impedance of the echo cancelling circuit comprises the capacitance component or not.

11. The signal transmitting and receiving circuit of claim 10 , wherein the signal transmitting module comprises a transmitting differential signal pair and the signal receiving module comprises a receiving differential signal pair, and the echo cancelling circuit comprises:
a first impedance unit with one of its two ends coupled to a positive end of the transmitting differential signal pair and the transformer and the other end coupled to a negative end of the receiving differential signal pair and the transformer; and
a second impedance unit with one of its two ends coupled to a negative end of the transmitting differential signal pair and the transformer and the other end coupled to a positive end of the receiving differential signal pair and the transformer.

12. The signal transmitting and receiving circuit of claim 11 , wherein the transformer comprises:
a first winding, coupled to the signal transmitting module, comprising a first coil and a second coil, and the first and the second coils comprising respectively a first polarity end and a second polarity end;
a second winding, coupled to the signal receiving module; and
a third winding, coupled to the telecommunication loop;
and the signal transmitting and receiving circuit further comprises:
a third impedance unit with its two ends coupled respectively to the first polarity end of the first coil and the first polarity end of the second coil; and
a fourth impedance unit with its two ends coupled respectively to the second polarity end of the first coil and the second polarity end of the second coil;
wherein a positive end of the transmitting differential signal pair is coupled to the first polarity end of the first coil and a negative end of the transmitting differential signal pair is coupled to the second polarity end of the second coil.

13. The signal transmitting and receiving circuit of claim 12 , wherein the second winding comprises a third coil and a fourth coil both comprising the first polarity end and the second polarity end, and a positive end of the receiving differential signal pair is coupled to the first polarity end of the third coil, the negative end of the receiving differential signal pair is coupled to the second polarity end of the fourth coil, the positive end of the transmitting differential signal pair is coupled to the first polarity end of the fourth coil, and the negative end of the transmitting differential signal pair is coupled to the second polarity end of the third coil.

14. The signal transmitting and receiving circuit of claim 12 , where a turns ratio of the third winding to the first winding is not equal to a turns ratio of the s

Assignees

• Realtek Semiconductor Corp

Inventors

• Chen Yung-Tai
• Li Cheng-Hsien
• Chu Hung-Chen
• Lin jian-ru

Classifications

• H04B3/20 Primary

  Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other · CPC title