Transceiver and communication method of digital subscriber line

1. A transceiver of digital subscriber line (DSL) capable of supporting a variety of DSL systems, comprising:

a transmission circuit including:

a transmission selector to receive an output signal and provide the output signal for a first DSL analog-front-end transmission circuit or a second DSL analog-front-end transmission circuit according to a transmission selection parameter;

the first DSL analog-front-end transmission circuit corresponding to a first DSL system to generate a first DSL transmission signal according to the output signal; and

the second DSL analog-front-end transmission circuit corresponding to a second DSL system to generate a second DSL transmission signal according to the output signal;

a hybrid circuit, coupled with the transmission circuit, to generate a line transmission signal according to the first DSL transmission signal or the second DSL transmission signal and generate a DSL reception signal according to a line reception signal, including:

a first echo canceller to carry out a first echo cancellation on the line reception signal; and

a second echo canceller to carry out a first DSL echo cancellation or a second DSL echo cancellation on the line reception signal according to an echo cancellation selection parameter, including:

a first filtering circuit to carry out the first DSL echo cancellation if the echo cancellation selection parameter indicates the first DSL system, and carry out the second DSL echo cancellation if the echo cancellation selection parameter indicates the second DSL system; and

a second filtering circuit to carry out a second echo cancellation according to a line impedance detection result or an echo cancellation amount estimation result; and

a reception circuit, coupled with the hybrid circuit, including:

a first DSL analog-front-end reception circuit corresponding to the first DSL system to generate a first DSL reception signal according to the DSL reception signal;

a second DSL analog-front-end reception circuit corresponding to the second DSL system to generate a second DSL reception signal according to the DSL reception signal; and

a reception selector to output the first DSL reception signal or the second DSL reception signal as an input signal according to a reception selection parameter.

2. The transceiver of DSL of claim 1 , wherein the first DSL system is an ADSL (Asymmetric Digital Subscriber Line) system and the second DSL system is a VDSL (Very-high-data-rate Digital Subscriber Line) system.

3. The transceiver of DSL of claim 1 , wherein the second echo canceller is further to carry out a second echo cancellation on the line reception signal according to a line impedance detection result or an echo cancellation amount estimation result.

4. The transceiver of DSL of claim 1 , wherein the first echo canceller is un-adjustable while the second echo canceller is adjustable.

5. The transceiver of DSL of claim 1 , further comprises:

a third echo canceller, coupled between the transmission circuit and the reception circuit, to carry out a third echo cancellation on the input signal.

6. The transceiver of DSL of claim 5 , wherein the third echo canceller is adjustable.

7. The transceiver of DSL of claim 1 , wherein the first echo canceller comprises:

at least one impedance to provide an impedance-matching effect and form a bridge configuration with a secondary winding of a transformer for echo cancellation; and

at least one passive filter, coupled with the at least one impedance, to carry out a predetermined filtering function for echo cancellation.

8. The transceiver of DSL of claim 1 , wherein the first filtering circuit includes at least one active filter and at least one passive filter while the second filtering circuit includes at least one active filter.

9. The transceiver of DSL of claim 1 , further comprises:

a third echo canceller, coupled between the transmission circuit and the reception circuit, to carry out a third echo cancellation on the input signal.

10. The transceiver of DSL of claim 9 , wherein the third echo canceller is adjustable.

11. A transceiver of digital subscriber line (DSL) capable of supporting a variety of DSL systems, comprising:

a transmission circuit to generate a first DSL transmission signal or a second DSL transmission signal according to an output signal;

a reception circuit to generate a first DSL reception signal or a second DSL reception signal according to a DSL reception signal, and output the first or second DSL reception signal as an input signal; and

a hybrid circuit which is coupled with the transmission circuit and the reception circuit to generate a line transmission signal according to the first DSL transmission signal or the second DSL transmission signal and generate the DSL reception signal according to a line reception signal, comprising:

a first echo canceller to carry out a first echo cancellation on the line reception signal; and

a second echo canceller to carry out a first DSL echo cancellation or a second DSL echo cancellation on the line reception signal according to a present DSL type, and/or carry out a second echo cancellation on the line reception signal according to a line impedance detection result or an echo cancellation amount estimation result, and the second echo canceller including:

a first filtering circuit to carry out the first DSL echo cancellation if the present DSL type corresponds to a first DSL system, and carry out the second DSL echo cancellation if the present DSL type corresponds to a second DSL system; and

a second filtering circuit to carry out the second echo cancellation according to the line impedance detection result or the echo cancellation amount estimation result.

12. The transceiver of DSL of claim 11 , further comprising:

a third echo canceller, which includes an active filter and is coupled between the transmission circuit and the reception circuit, to carry out a third echo cancellation on the input signal.

13. The transceiver of DSL of claim 11 , wherein the first echo canceller is un-adjustable while the second echo canceller is adjustable.

14. The transceiver of DSL of claim 11 , wherein the first echo canceller includes:

at least one impedance to provide an impedance-matching effect and form a bridge configuration with a secondary winding of a transformer for echo cancellation; and

at least one passive filter, coupled with the at least one impedance, to carry out a predetermined filtering function for echo cancellation.

15. The transceiver of DSL of claim 11 , wherein the transmission circuit is to generate the first DSL transmission signal or the second DSL transmission signal under the control of a transmission selection parameter, and the reception circuit is to output the first DSL reception signal or the second DSL reception signal as the input signal under the control of a reception selection parameter.

16. The transceiver of DSL of claim 11 , wherein the first DSL transmission signal and the first DSL reception signal correspond to an ADSL (Asymmetric DSL) system while the second DSL transmission signal and the second DSL reception signal correspond to a VDSL (Very-high-data-rate DSL) system.

17. A communication method of digital subscriber line (DSL) capable of supporting a variety of DSL systems and being carried out by a DSL transceiver, comprising the following steps:

generating a first DSL transmission signal according to an output signal if a transmission selection parameter indicates a first DSL system, and generating a second DSL transmission signal according to the output signal if the transmission selection parameter indicates a second DSL system;

generating a line transmission signal according to the first or second DSL transmission signal;

receiving a line reception signal and carrying out a constant first echo cancellation on the line reception signal to thereby generate a first echo cancellation signal;

carrying out a first DSL echo cancellation or a second DSL echo cancellation on the line reception signal according to a present DSL type and/or carrying out a second echo cancellation on the line reception signal according to a line impedance detection result or an echo cancellation amount estimation result, so as to generate a second echo cancellation signal, while the step of generating the second echo cancellation signal is capable of:

carrying out the first DSL echo cancellation if the present DSL type corresponds to a first DSL system, and carrying out the second DSL echo cancellation if the present DSL type corresponds to a second DSL system; and

carrying out the second echo cancellation according to the line impedance detection result or the echo cancellation amount estimation result;

generating a DSL reception signal according to the first and second echo cancellation signals; and

generating a first DSL reception signal or a second DSL reception signal according to the DSL reception signal, and outputting the first DSL reception signal or the second DSL reception signal as an input signal.