Issue No. 03 - May/June (1985 vol. 2)
Douglas Shirachi , Zehntel Automation Systems
Five methods for verifying coder/decoder operation in telecommunications PC boards provide the engineer optimal fault coveragewith minimal test time. All methods support a dual-purpose testing strategy: (1) to conduct an in-circuit board test to detectassembly errors before a functional test and (2) to conduct a functional test in which stress is applied to detect marginalperformance. All methods involve the use of synchronized analog and digital signals with optional IEEE-488 instruments fordetail inspection. The first two methods, coder testing and decoder testing, are appropriate techniques for traditional in-circuittesting. The next two methods, analog loopback testing and digital loopback testing, are considered quasi-functional tests.The test signal path between stimulus and response may traverse a number of different ICs but not dynamically test completeboard operation. The last method, functional instruments testing, allows detailed performance parameters specific to the devicebeing tested to be verified. Sample test programs are presented for each method.
D. Shirachi, "Codec Testing Using Synchronized Analog And Digital Signals," in IEEE Design & Test of Computers, vol. 2, no. , pp. 56-63, 1985.