Techniques for testing an electronic system using in-line signal distortion

• US 7,133,795 B1
• Filed: 12/23/2004
• Issued: 11/07/2006
• Est. Priority Date: 12/23/2004
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Iaciofano, Edward, Laviolette, Thomas
• Primary Examiner(s): Nghiem, Michael
• Assistant Examiner(s): LE, JOHN H
• Application Number:
  US11/020,722
• Time in Patent Office: 684 Days
• Field of Search: 702/39, 702/108, 702/117, 702/118, 702/122, 702/182, 702/183, 702/185, 702/186, 701/16, 701/133, 714/43, 714/715, 714/724, 714/725, 455/323, 710/38, 711/113, 382/251, 375/240.26
• US Class Current: 702/108
• CPC Class Codes: G01R 31/3171 BER [Bit Error Rate] test
• CPC Class Codes: G01R 31/31711 Evaluation methods, e.g. shmoo plots

Abstract

A technique for testing an electronic system (e.g., a computer system) involves intercepting an initial signal of the electronic system, modifying the initial signal with a distortion to form a distorted signal, and introducing the distorted signal into the electronic system in place of the initial signal. The technique further involves obtaining, from the electronic system, a result having one of (i) a first value indicating that the electronic system handled the distorted signal in a normal operating mode, and (ii) a second value indicating that the electronic system handled the distorted signal in an error handling mode which is different than the normal operating mode.

Claims

1. A method for testing an electronic system, the method comprising:

intercepting an initial signal of the electronic system;

modifying the initial signal with a distortion to form a distorted signal;

introducing the distorted signal into the electronic system in place of the initial signal; and

obtaining, from the electronic system, a result having one of (i) a first value indicating that the electronic system handled the distorted signal in a normal operating mode, and (ii) a second value indicating that the electronic system handled the distorted signal in an error handling mode which is different than the normal operating mode;

wherein the electronic system is a computer system;

wherein intercepting the initial signal includes;

receiving, as the initial signal, a serial data stream which is generated dynamically by the computer system in response to computerized operations performed by individual devices of the computer system; and

wherein receiving the serial data stream includes;

obtaining, as the serial data stream, a non-static, real-time electrical signal en route from a first device of the computer system toward a second device of the computer system.

2. The method of claim 1 wherein obtaining the non-static, real-time electrical signal includes:

acquiring, as the non-static, real-time electrical signal, a differential pair signal.

3. The method of claim 2 wherein acquiring the differential pair signal includes:

temporarily buffering the differential pair signal in an analog buffer circuit to preserve any pre-existing distortions in the differential pair signal.

4. The method of claim 1, further comprising:

setting a switch from a first position which causes introduction of the distorted signal into the computer system in place of the initial signal to a second position which causes introduction of the initial signal into the computer system.

5. The method of claim 4 wherein the initial signal passes through an input analog buffer circuit prior to reaching the switch;

wherein an output analog buffer circuit is configured to output the distorted signal; and

wherein setting the switch from the first position to the second position includes;

circumventing an output analog buffer circuit to introduce the initial signal rather than the distorted signal into the computer system.

6. The method of claim 1 wherein the initial signal has an initial amplitude, and wherein modifying the initial signal with the distortion to form the distorted signal includes:

changing the initial amplitude to a new amplitude which is different than the initial amplitude to provide at least part of the distortion forming the distorted signal.

7. The method of claim 1 wherein the initial signal has an initial rise time, and wherein modifying the initial signal with the distortion to form the distorted signal includes:

changing the initial rise time to a new rise time which is different than the initial rise time to provide at least part of the distortion forming the distorted signal.

8. The method of claim 1 wherein the initial signal has an initial fall time, and wherein modifying the initial signal with the distortion to form the distorted signal includes:

changing the initial fall time to a new fall time which is different than the initial fall time to provide at least part of the distortion forming the distorted signal.

9. The method of claim 1 wherein modifying the initial signal with the distortion to form the distorted signal includes:

introducing white noise as at least part of the distortion to form the distorted signal.

10. The method of claim 9 wherein modifying the initial signal with the distortion to form the distorted signal further includes:

changing at least one of an amplitude of the initial signal, a rise time of the initial signal, and a fall time of the initial signal prior to introducing the white noise.

11. The method of claim 1, further comprising:

disconnecting a conductor of the computer system to access the non-static, real-time electrical signal from a side of the conductor leading to the first device of the computer system.

12. The method of claim 11 wherein introducing the distorted signal into the computer system includes:

injecting the distorted signal into another side of the conductor leading to the second device of the computer system.

13. The method of claim 1 wherein the individual devices of the computer system connect in a daisy-chained manner;

and wherein obtaining the non-static, real-time electrical signal includes;

acquiring, as the non-static, real-time electrical signal, a point-to-point signal which is outputted from the first device toward the second device.

14. An apparatus for testing an electronic system, comprising:

an input stage which is configured to intercept an initial signal of the electronic system;

a control stage coupled to the input stage, the control stage being configured to modify the initial signal with a distortion to form a distorted signal; and

an output stage coupled to the control stage, the output stage being configured to introduce the distorted signal into the electronic system in place of the initial signal, the control stage enabling a user to select characteristics of the distortion and obtain, from the electronic system, a result having one of (i) a first value indicating that the electronic system handled the distorted signal in a normal operating mode, and (ii) a second value indicating that the electronic system handled the distorted signal in an error handling mode which is different than the normal operating mode;

wherein the electronic system is a computer system, and wherein the input stage includes;

an input analog buffer circuit configured to (i) receive, as the initial signal, a dynamically-generated, real-time differential pair signal in response to computerized operations performed by individual devices of the computer system, and (ii) preserve any pre-existing distortions in the dynamically-generated, real-time differential pair signal.

15. The apparatus of claim 14 wherein the output stage includes an output analog buffer circuit which is configured to output the distorted signal;

and wherein the apparatus further comprises;

a switch coupled to the input analog buffer circuit, the switch being configured to switch between (i) a first position which connects the input analog buffer circuit to the control stage to output the distorted signal from the output analog buffer, and (ii) a second position which circumvents the control stage and the output analog buffer circuit to reintroduce the initial signal into the computer system.

16. The apparatus of claim 14 wherein the initial signal has an initial amplitude, and wherein the control stage includes:

an amplitude adjustment circuit which is configured to change the initial amplitude to a new amplitude which is different than the initial amplitude to provide at least part of the distortion forming the distorted signal.

17. The apparatus of claim 14 wherein the initial signal has an initial rise time, and wherein the control stage includes:

a rise time adjustment circuit which is configured to change the initial rise time to a new rise time which is different than the initial rise time to provide at least part of the distortion forming the distorted signal.

18. The apparatus of claim 14 wherein the initial signal has an initial fall time, and wherein the control stage includes:

a fall time adjustment circuit which is configured to change the initial fall time to a new fall time which is different than the initial fall time to provide at least part of the distortion forming the distorted signal.

19. The apparatus of claim 14 wherein the control stage includes:

a noise generator which is configured to introduce white noise as at least part of the distortion to form the distorted signal.

20. The apparatus of claim 14 wherein the individual devices of the computer system connect in a daisy-chained manner;

and wherein the input analog buffer circuit includes;

circuitry configured to acquire, as the dynamically-generated, real-time differential pair signal, a point-to-point signal which is outputted from a first individual device of the computer system toward a second individual device of the computer system.

21. An apparatus for testing a computer system, comprising:

an input stage which is configured to intercept an initial signal of the computer system;

an output stage which is configured to introduce a distorted signal into the computer system in place of the initial signal; and

means, coupled to the input stage and the output stage, for modifying the initial signal with a distortion to form the distorted signal, the means for modifying including means for enabling a user to select characteristics of the distortion to obtain, from the computer system, a result having one of (i) a first value indicating that the computer system handled the distorted signal in a normal operating mode, and (ii) a second value indicating that the computer system handled the distorted signal in an error handling mode which is different than the normal operating mode;

wherein the electronic system is a computer system, and wherein the input stage includes;

an input analog buffer circuit configured to (i) receive, as the initial signal, a dynamically-generated, real-time differential pair signal in response to computerized operations performed by individual devices of the computer system, and (ii) preserve any pre-existing distortions in the dynamically-generated, real-time differential pair signal.

22. The apparatus of claim 21 wherein the individual devices of the computer system connect in a daisy-chained manner;

and wherein the input analog buffer circuit includes;

circuitry configured to acquire, as the dynamically-generated, real-time differential pair signal, a point-to-point signal which is outputted from a first individual device of the computer system toward a second individual device of the computer system.