04496900 is referenced by 50 patents and cites 5 patents.

The tester and method for nondestructively detecting nonlinearity faults in conductors includes the application of a composite AC and DC drive signal to the device under test in such manner that nonlinearities in the device under test produce fault signals including second harmonics, due to local changes of resistance caused by ohmic heating. Electronic filters are used to select out and amplify the second harmonic only, eliminating the direct current and fundamental frequency components of the initial test pulse, plus third and subsequent harmonics. The filtered second harmonic signals from the device under test are then phase-compared to a phase-shifted second harmonic signal produced by a frequency doubler from the test signal generator oscillator to cancel out the second harmonic signals from the good conductor; the remaining phase anomaly signals control a threshold detector remaining to provide fault indication.

Title
Nonlinearity detection using fault-generated second harmonic
Application Number
6/373318
Publication Number
4496900
Application Date
April 30, 1982
Publication Date
January 29, 1985
Inventor
Arnold Halperin
Peekskill
NY, US
Thomas H Di Stefano
Bronxville
NY, US
Agent
Carl C Kling
Assignee
International Business Machines Corporation
NY, US
IPC
G01N 27/00
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