Circuit tester
AssigneeGenRad, Inc.
InventorRobert G. Fulks
Life of this patent
Estimating the term…
Abstract
A tester (10) for testing an electronic circuit (22) has test terminals (18a-d) that are to be connected to the terminals (20a-d) of the circuit under test. The tester terminals (18a-d) are placed in the states required for testing by formatter circuits (32a-d) in accordance with state codes generated by state-code generators (24a-d). However, the state-code generators (24a-d) are not required to generate every code as quickly as those codes are needed by the formatters (32a-d), because first-in, first-out memory stacks (30a-d) are interposed between the state-code generators (24a-d) and the formatters (32a-d). This permits the state-code generators (24a-d) to employ relatively slow--and thus relatively inexpensive--memories (26).
Claims2
In a circuit tester, having a plurality of tester terminals for connection to terminals of a unit under test, for performing a test by placing the terminals in a sequence of terminal states, control circuitry for controlling the terminal states of the tester terminals to specify the test operations to be performed, the control circuitry comprising:
- A. a first-in, first-out memory for storing state codes applied thereto;
- B. an advance-time machine for generating state codes representing terminal states and for applying those state codes to the first-in, first-out memory;
- C. a real-time machine for fetching those state codes from the first-in, first-out memory, and for placing the tester terminals in the states represented by the fetched state codes concurrently with the application of state codes to the first-in, first-out memory, and with a timing independent of that with which the advance-time machine applies state codes to the memory, so that the real-time machine places the terminals in the states represented by the state codes that the advance-time machine generates, whereby the control circuitry can change terminal states at a rate different from that at which it generates state codes.
Dependencies are inferred from the claim text.