Methods and apparatus for optimizing lists of waveforms

• US 20050080575A1
• Filed: 10/14/2003
• Published: 04/14/2005
• Est. Priority Date: 10/14/2003
• Status: Active Grant

• Current Assignee: Advantest Corporation
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Hildebrant, Andrew Steven
• Granted Patent: US 7,010,453 B2
• Time in Patent Office: Days
• US Class Current: 702/70
• CPC Class Codes: G01R 31/2841 Signal generators
• CPC Class Codes: G01R 31/31919 Storing and outputting test patterns G01R31/31924 takes precedence; arithmetic and random test patterns generator
• CPC Class Codes: G01R 31/31921 using compression techniques, e.g. patterns sequencer
• CPC Class Codes: G01R 31/31928 Formatter driver, receiver details G01R31/31924

Abstract

A list of waveforms is received (the list being one that is to be driven to or received from a pin of a device under test). The list of waveforms is de-interleaved to form lists of non-interleaved waveforms. Each list of non-interleaved waveforms is then optimized by combining at least two of its entries. By way of example, the above method may be implemented by program code stored on a number of computer readable media, or by a circuit tester having program code for implementing same.

Claims

1. A method, comprising:

receiving a list of waveforms that is to be driven to or received from a pin of a device under test;

de-interleaving the list of waveforms to form lists of non-interleaved waveforms; and

optimizing each list of non-interleaved waveforms by combining at least two of its entries.

2. The method of claim 1, wherein entries in one of the lists of non-interleaved waveforms are combined based on identity of the entries.

3. The method of claim 1, wherein entries in one of the lists of non-interleaved waveforms are combined by masking an entry of one type with an entry of another type.

4. The method of claim 3, wherein said maskings are chosen to preserve a greatest number of test sample points.

5. The method of claim 1, wherein entries in one of the lists of non-interleaved waveforms are combined by masking two of the list'"'"'s entries with a waveform not in the list.

6. The method of claim 1, wherein:

each entry in the list of waveforms is associated with a weight;

the weight associated with an entry in the list of waveforms is associated with a corresponding entry in each of the lists of non-interleaved waveforms; and

as entries in the lists of non-interleaved waveforms are combined, their associated weights are combined.

7. The method of claim 6, wherein entries in one of the lists of non-interleaved waveforms are combined to preserve a greatest number of test sample points.

8. The method of claim 6, further comprising, ordering the entries of each optimized list in accordance with the weights of the entries, and then re-interleaving the optimized ordered lists.

9. The method of claim 6, wherein the weights are statistical weights.

10. The method of claim 6, wherein the weights are priority weights.

11. The method of claim 1, further comprising, as each list of non-interleaved waveforms is optimized, maintaining the same number of entries in each optimized list.

12. The method of claim 1, further comprising, re-interleaving the optimized lists, and presenting the re-interleaved list to a user.

13. The method of claim 1, further comprising, combining entries in each list of non-interleaved waveforms, until each list of non-interleaved waveforms comprises fewer entries than a waveform memory size.

14. The method of claim 1, further comprising, using each optimized list to program a different waveform memory of a circuit tester.

15. Apparatus, comprising:

a number of computer readable media; and

program code, stored on the computer readable media, defining;

an interface to receive a list of waveforms that is to be driven to or received from a pin of a device under test;

program code to de-interleave the list of waveforms to form lists of non-interleaved waveforms; and

program code to optimize each of the lists of non-interleaved waveforms by combining at least two of its entries.

16. The apparatus of claim 15, wherein the program code further comprises an interface to receive an interleave factor;

the interleave factor being used by the program code to de-interleave the list of waveforms.

17. The apparatus of claim 15, wherein the program code combines entries in each list of non-interleaved waveforms until each list of non-interleaved waveforms comprises fewer entries than a waveform memory size.

18. The apparatus of claim 15, further comprising program code to re-interleave the optimized lists and present the re-interleaved list to a user.

19. The apparatus of claim 15, further comprising program code to order the entries of each optimized list and re-interleave the optimized ordered lists.

20. A circuit tester, comprising:

a plurality of driving probes and receiving probes;

a plurality of waveform memories;

a switching network to associate plural multiplexed waveform memories with ones of said probes;

an interface to receive lists of waveforms that are to be driven to and received from said probes;

program code to de-interleave each list of waveforms, thereby forming a set of lists of non-interleaved waveforms for each list of waveforms;

program code to optimize each list of non-interleaved waveforms by combining at least two of its entries; and

program code to program ones of the waveform memories based on the optimized lists.

21. The circuit tester of claim 20, wherein the program code further comprises an interface to receive an interleave factor;

the interleave factor being used by the program code to de-interleave the list of waveforms.

22. The circuit tester of claim 20, wherein the program code combines entries in each list of non-interleaved waveforms until each list of non-interleaved waveforms comprises fewer entries than a size of the waveform memories.

23. The circuit tester of claim 20, further comprising program code to re-interleave the optimized lists and present the re-interleaved list to a user.