This research is on testing large scale analog and mixed-signal circuits. There are two tasks being undertaken. First is to develop a decomposition approach for testing large scale analog and mixed-signal circuits. A time domain decomposition method, which does not break interconnections, is being explored. It is based on taking voltage measurements at partition points and formulating new test equations at these nodes. Thus measurement errors are reduced to a local area and computations are performed in each subcircuit. Second is to establish a test strategy for automatic testing of large scale circuits. A set of pre-test computations to be done off-line during the design stage or before manufacturing test is being developed. Methods for extracting parameters during test are being investigated. A set of post-test computations using the parameters extracted during the test is being developed. Software for doing the tests is being built and benchmark circuits are being tested.