Tester calibration procedure which includes fixturing
First Claim
1. A system for calibrating testers comprising:
- (a) a signal generator for generating an internal timing signal;
(b) at least one test module connected to said signal generator for interfacing to a device under test;
(c) a test probe for receiving test signals at various locations;
(d) a time measurement device, connected to said signal generator, for measuring the time difference between edges of a signal generated by said signal generator and edges of test signal received by said test probe;
(e) a probe interface channel, connected to said test probe and to said time measurement device, for receiving test signals from said test probe; and
(f) wherein said test module comprises a plurality of test-module channels for sending signals to and receiving signals from a device under test.
3 Assignments
0 Petitions
Accused Products
Abstract
A system and method for calibrating testers. A reference timing signal and an internal timing signal used in tester calibration are generated within a tester. A first calibration is performed wherein test module channel characteristics are measured and recorded, and an adjustment value is determined to correct the time placement of the internal timing signal. Driver and receiver delays are adjusted based on the characteristics measured in this first calibration, and the internal timing signal is adjusted as well. A second calibration is performed wherein temporal relationships between the adjusted internal timing signal and signals at the test module channel mint pins are determined. Driver and receiver delays are adjusted based on the results of this calibration. An optional calibration is performed wherein temporal relationship between the adjusted internal timing signal and signals at the board-interface end of a test fixture are measured. Using these measurements and the measurements obtained in the second calibration, a test fixture characterization is performed and recorded. Delays of the drivers and receivers are again adjusted to account for the fixture characteristics. Additional calibration methods provided by the present invention include a manual multi-module calibration to keep test module channels aligned when a new module is designated as the master module, and a manual synchronization clock calibration to deskew drivers and receivers relative to an external clock supplied by the device under test.
43 Citations
17 Claims
-
1. A system for calibrating testers comprising:
-
(a) a signal generator for generating an internal timing signal; (b) at least one test module connected to said signal generator for interfacing to a device under test; (c) a test probe for receiving test signals at various locations; (d) a time measurement device, connected to said signal generator, for measuring the time difference between edges of a signal generated by said signal generator and edges of test signal received by said test probe; (e) a probe interface channel, connected to said test probe and to said time measurement device, for receiving test signals from said test probe; and (f) wherein said test module comprises a plurality of test-module channels for sending signals to and receiving signals from a device under test. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
-
Specification