Method and apparatus for determining crosstalk

• US 6,553,075 B1
• Filed: 01/12/1999
• Issued: 04/22/2003
• Est. Priority Date: 01/12/1999
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Sisk, James R., McGhee, David W.
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): TRAN, KHANH C
• Application Number:
  US09/228,686
• Time in Patent Office: 1,561 Days
• Field of Search: 375/254, 375/219, 375/222, 375/224, 375/225, 375/227, 375/228, 375/295-296, 375/346, 370/252, 370/468, 370/480, 370/482, 379/1.03, 379/12, 379/22, 379/22.02, 379/22.04, 379/22.08, 379/23, 379/27.01, 379/27.03, 379/29.03, 379/32.01, 379/32.04
• US Class Current: 375/254
• CPC Class Codes: H04B 1/1027 assessing signal quality or detecting noise/interference for the received signal
• CPC Class Codes: H04B 3/46 Monitoring; Testing
• CPC Class Codes: H04L 1/20 using signal quality detector

Abstract

A system to analyze and compensate for noise on a transmission line (35) is provided. The system comprises a transmission card which includes a transceiver (32), and a microprocessor (34) attached to the transceiver (32). The system also comprises a transmission line (35) coupled to the transceiver (32) and at least one customer premise equipment (38) coupled to the transceiver (32) by the transmission line (35). The microprocessor (34) is operable to monitor the transmission line (32) and determine the signal-to-noise ratio on the line as a function of frequency, and adjust the rate of transmission in terms of bandwidth in terms of bits as a function of frequency.

Claims

1. A method for determining noise on a transmission line comprises of the steps of training the line at a low bandwidth rate;

analyzing the line using a microprocessor in order to determine noise as a function of frequency; and

adjusting the transmission rate based on the determined noise and an expected worst case level of noise for a transmitted signal to provide a margin between the noise on the line and the transmitted signal, wherein the transmit signal is transmitted using a CAP ADSL scheme and noise is determined as a combined gain and signal-to-noise ratio value.

2. The method of claim 1, wherein the noise detection is done by a digital signal processor.

3. A system to analyze and compensate for noise on a transmission line comprising:

a transmission card including;

a transceiver; and

a microprocessor attached to the transceiver;

a transmission line coupled to the transceiver; and

,

at least one customer premise equipment coupled to the transceiver by the transmission line;

wherein the microprocessor is operable to monitor the transmission line and determine noise on the line as a function of frequency, and adjust the rate of transmission based on the determined noise and an expected worst case level of noise for a transmitted signal transmission to provide a margin between the noise and a transmitted signal, wherein the transmission is transmitted using a CAP ADSL scheme and noise is determined as a combined gain and signal-to-noise ratio value.

4. The system of claim 3, wherein the microprocessor is a digital signal processor.

5. A method for determining noise on a transmission line comprises of the steps of:

training the line at a low bandwidth rate;

analyzing the line using a microprocessor in order to determine noise as a function of frequency; and

adjusting the transmission rate to provide a margin between the noise on the line and the transmitted signal, wherein the transmit signal is transmitted using a CAP ADSL scheme and noise is determined as a combined gain and signal-to-noise ratio value.

6. The method of claim 5, wherein the noise detection is done by a digital signal processor.

7. A system to analyze and compensate for noise on a transmission line comprising:

a transmission card including;

a transceiver; and

a microprocessor attached to the transceiver;

a transmission line coupled to the transceiver; and

,

at least one customer premise equipment coupled to the transceiver by the transmission line;

wherein the microprocessor is operable to monitor the transmission line and determine noise on the line as a function of frequency, and adjust the rate of transmission to provide a margin between the noise and a transmitted signal, wherein the transmission is transmitted using a CAP ADSL scheme and noise is determined as a combined gain and signal-to-noise ratio value.

8. The system of claim 7, wherein the microprocessor is a digital signal processor.