Front end interface for data receiver

• US 7,519,130 B2
• Filed: 01/18/2005
• Issued: 04/14/2009
• Est. Priority Date: 01/18/2005
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Cordrey-Gale, Matt R., Sorna, Michael A., Hsu, Louis L., Mason, James S., Xu, Huihao, Selander, Karl D., Murfet, Philip J.
• Primary Examiner(s): Payne; David C
• Assistant Examiner(s): Dsouza; Adolf
• Application Number:
  US10/905,705
• Publication Number:
  US 20060159200A1
• Time in Patent Office: 1,547 Days
• Field of Search: 327/70, 327/355, 326/30, 702/58, 324/534
• US Class Current: 375/292
• CPC Class Codes: H04L 25/0274 Arrangements for ensuring balanced coupling
• CPC Class Codes: H04L 25/0296 Arrangements to ensure DC-balance

Abstract

A data receiver is provided which includes a front end interface circuit having an alternating current (AC) transmission receiving mode and a direct current (DC) transmission receiving mode. The front end interface circuit includes an offset compensation circuit operable to compensate a DC voltage offset between a pair of differential signals input to the data receiver. The front end interface circuit further includes an AC/DC selection unit operable to switch between (a) the DC transmission receiving mode, and (b) the AC transmission receiving mode, such that the data receiver is operable in (i) the DC transmission mode in which the offset compensation circuit is disabled, (ii) the DC transmission mode in which the offset compensation circuit is enabled, (iii) the AC transmission mode in which the offset compensation circuit is disabled, and (iv) the AC transmission receiving mode in which the offset compensation circuit is enabled.

Claims

1. A method of receiving data, comprising:

utilizing a control signal at a data receiver to switch between an alternating current (AC) transmission receiving mode for receiving an AC coupled mode data signal from a pair of differential signal inputs and a direct current (DC) transmission receiving mode for receiving a DC coupled mode data signal from the pair of differential signal inputs; and

operating the data receiver while compensating for DC voltage offset during the AC transmission receiving mode when the offset compensation circuit is enabled, operating the data receiver without compensating for DC voltage offset during the AC transmission receiving mode when the offset compensation circuit is disabled, operating the data receiver while compensating for DC voltage offset during the DC transmission receiving mode when the offset compensation circuit is enabled, and operating the data receiver during the DC transmission receiving mode without compensating for DC voltage offset;

injecting in an upchannel direction, onto transmission lines provided for carrying the differential signal inputs a first test data signal onto a first one of the transmission lines operable to carry a first one of the differential signal inputs, and a second test data signal onto a second one of the transmission lines operable to carry a second one of the differential signal inputs; and

at a transmitter connected to at least one of the first and second transmission lines, detecting faults on the at least one of the first and second transmission lines.

2. The method as claimed in claim 1, wherein the first and second test data signals are simultaneously injected in the upchannel direction onto the first and second transmission lines.

3. The method as claimed in 1, further comprising receiving the first and second injected test data signals by the data receiver to test the data receiver.