Mastering Mixed-Signal
Synchronisation
True mixed-signal testing requires coherency between the digital and analogue instrumentation. IntegraTEST Series 20 does not only offer frequency coherency, but also phase coherency. This is achieved using one common frequency reference for the mixed-signal test resources, digital as well as analogue.
The synchronisation achieved allows for example an A/D converter to be tested without facing the problem of spectral leakage ("skirts" on a given frequency composant). The synchronisation feature also makes it possible to run e.g. a mixed-signal stimuli at one frequency and sampling at another frequency, but still derived from the same master frequency. The synchronisation obtained goes by various names, including M/N synchronisation, prime ration locking, etc.
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The rationale behind the synchronisation is the fact that a growing part of mixed-signal testing is based upon complex mathematical DSP based algorithms. A given mathematical precision in a test may be lost, if for example the test vector samples do not fall in the correct sample points over exactly the right time interval.
LabVIEW Based Graphic User Interface for Tester Control and Development Environment
The "de facto industry standard" dataflow programming language, the National Instrument LabVIEW, is generally used for graphics user interfaces for the tester control and the development environment. LabVIEW has the advantage of being faster in programming than traditional line code programming styles. It is typically up to 3-5 times faster, and its user friendliness is significant. Compiled code for fast program execution with more than 250 instruments from over 40 different companies.
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Non-coherent test results in "skirts" on the signal. The upper signal is coherent, the lower one is non-coherent. |
SequenTEST, the overall test sequencer of the mixed-signal system, is also based upon LabVIEW and a version of LimiTEST executing under SequenTEST is also based upon LabVIEW. Similarly for the InstruWARE software instruments, the user interfaces and the commands for the instruments are LabVIEW based, and all commands to the software instruments are called from a LabVIEW program.
The LabVIEW programs feature: On- and Off-line test development for increased test preparation.
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Examples of the Sequence Editor programming interface. In the left GUI, the main window is shown, and above it the set-up of power supplies is facilitated. |
