US4897842A
Expired / Lapsed
US
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Integrated circuit signature analyzer for testing digital circuitry
Assignee: Ampex Corp
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Filing: 1987-11-05
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Granted: 1990-01-30
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Expires: 2007-11-05
Abstract
Abstract A system for testing digital circuitry includes a signature generator that is connected to a plurality of nodes in the circuit to be tested and that generates signature words unique to identical streams of binary data signals or clocking signals. A multiplexer sequentially directs streams of signals to the signature generator from selected test nodes, or data streams from a plurailty of nodes can be signaturized simultaneously.
Inventors
- 👤 William S. Herz
- 👤 Robert A. Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 03:35
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/22; G06F11/26; G06F11/273; G06F11/277
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
85 words
A system for testing digital electronic circuits comprising: generator means integrated with circuits to be tested for generating words that are unique to identical streams of binary signals; connecting means that connect the generator means to receive binary signals from a plurality of nodes in the digital circuit to be tested such that the generator means is simultaneously provided with bit streams from more that two nodes of the plurality of nodes; and comparator and storage means for receiving, storing and comparing consecutively-generated signature words.
Claim 2
Independent Claim
85 words
A system for testing digital electronic circuits comprising: generator means integrated with circuits to be tested for generating words that are unique to identical streams of binary signals; connecting means that connect the generator means to receive binary signals from a plurality of nodes in the digital circuit to be tested such that the generator means is simultaneously provided with bit streams from more that two nodes of the plurality of nodes; and comparator and storage means for receiving, storing and comparing consecutively-generated signature words.
Claim 3
Independent Claim
104 words
A system for testing the stability of streams of binary signals at multiple nodes in electronic digital circuits comprising: generator means connected for receiving binary bit streams simultaneously from at least two nodes and operative for producing signature words unique to identical streams of binary signals; selector means that connect the generator means to receive streams of binary signals from at least two nodes in the digital circuit to be tested; comparator means that receive and compare consecutive signature words generated by the generator means; and means responsive to the comparator means for indicating the presence and absence of identity between consecutively-generated signature words.
Claim 4
Independent Claim
104 words
A system for testing the stability of streams of binary signals at multiple nodes in electronic digital circuits comprising: generator means connected for receiving binary bit streams simultaneously from at least two nodes and operative for producing signature words unique to identical streams of binary signals; selector means that connect the generator means to receive streams of binary signals from at least two nodes in the digital circuit to be tested; comparator means that receive and compare consecutive signature words generated by the generator means; and means responsive to the comparator means for indicating the presence and absence of identity between consecutively-generated signature words.
Claim 5
Dependent Claim
29 words
A system according to claim 2 further including counter means responsible to the comparator means to count the number of consecutive identical signature words generated by the generator means.
Claim 6
Dependent Claim
31 words
A system according to claim 2 wherein the connecting means comprises a multiplexer means that receives the bit streams from the nodes and directs the streams sequentially to the generator means.
Claim 7
Independent Claim
85 words
A system for detecting the stability of clock intervals in streams of clocking signals in digital electronic circuits comprising: generator means connected to the nodes of a circuit under test to generate signature words unique to identical streams of edges of clock signals; comparator means connected to the generator means for comparing consecutive signature words generated by the generator means; and means connected to the comparator means for indicating lack of identity between consecutively-generated signature words and, thereby for indicating whether clocking intervals are stable.
Claim 8
Independent Claim
85 words
A system for detecting the stability of clock intervals in streams of clocking signals in digital electronic circuits comprising: generator means connected to the nodes of a circuit under test to generate signature words unique to identical streams of edges of clock signals; comparator means connected to the generator means for comparing consecutive signature words generated by the generator means; and means connected to the comparator means for indicating lack of identity between consecutively-generated signature words and, thereby for indicating whether clocking intervals are stable.
Claim 9
Dependent Claim
26 words
A system according to claim 5 further including memory means that stores signature words for comparison with the signature words generated by the signature generator means.
Claim 10
Dependent Claim
79 words
A process for testing digital electronic circuitry with an integral signature analyzer comprising the steps of: from a plurality of nodes of the circuit to be tested, directing simultaneous streams of binary data to a signature generator; generating signature words that are unique to identical streams of binary data; comparing generated signature words with signature words that are stored in a memory device; comparing consecutively-generated signature words; and indicating the presence and absence of identity between compared signature words.
Claim 11
Dependent Claim
79 words
A process for testing digital electronic circuitry with an integral signature analyzer comprising the steps of: from a plurality of nodes of the circuit to be tested, directing simultaneous streams of binary data to a signature generator; generating signature words that are unique to identical streams of binary data; comparing generated signature words with signature words that are stored in a memory device; comparing consecutively-generated signature words; and indicating the presence and absence of identity between compared signature words.
Claim 12
Dependent Claim
20 words
A process according to claim 7 including the step of counting the number of consecutive signature words that are identical.
Claim 13
Dependent Claim
37 words
A process according to claim 17 wherein, after an indication is obtained that two consecutive signature words are different, streams of binary data are directed to the signature analyzer serially and sequentially from nodes to be tested.
Claim 14
Dependent Claim
40 words
A process according to claim 22 including the steps of obtaining signature words from nodes of a correctly operating circuit of the same kind as the one under test, and storing the obtained signature words in an external memory device.
Claim 15
Dependent Claim
54 words
A process for testing the stability of clocking intervals in digital electronic circuits comprising the steps of: directing streams of clocking pulses to a signature analyzer; generating signature words that are unique to identical streams of clocking pulses; comparing consecutively-generated signature words; and indicating the presence and absence of identity between consecutive signature words.
Claim 16
Dependent Claim
54 words
A process for testing the stability of clocking intervals in digital electronic circuits comprising the steps of: directing streams of clocking pulses to a signature analyzer; generating signature words that are unique to identical streams of clocking pulses; comparing consecutively-generated signature words; and indicating the presence and absence of identity between consecutive signature words.
Claim 17
Dependent Claim
34 words
A process according to claim 11 further including the steps of comparing generated signature words with signature words that are generated from correctly operating circuits of the same kind as the one under test.
Claim 18
Independent Claim
94 words
A system for testing digital electronic circuits comprising: generator means integrated with circuits to be tested and selectively connectable for generating signature words in response to edges of clocking signals, which words are unique to identical streams of binary signals; connecting means that connect the generator means to receive binary signals from a plurality of nodes in the digital circuit to be tested; and comparator means connected to receive and compare signature words generated by the generator means with stored signature words to indicate the stability of clocking intervals for the circuits being tested.
Claim 19
Independent Claim
94 words
A system for testing digital electronic circuits comprising: generator means integrated with circuits to be tested and selectively connectable for generating signature words in response to edges of clocking signals, which words are unique to identical streams of binary signals; connecting means that connect the generator means to receive binary signals from a plurality of nodes in the digital circuit to be tested; and comparator means connected to receive and compare signature words generated by the generator means with stored signature words to indicate the stability of clocking intervals for the circuits being tested.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-01-29 | 1993-07-31 | 1994-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-29 | 1997-07-31 | 1998-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-29 | 2001-07-31 | 2002-01-30 | $7700.00 | Window Closed / Lapsed |