Testing results of chopper based integrator prototypes for the ITER magnetics

Several design variants of chopper-based digital signal integrators have been tested to evaluate the optimal solution to achieve the ITER magnetics diagnostic requirements. A maximum flux-equivalent drift of 500 mu V.s/hour is one of the key ITER magnetics diagnostic constraints for the integrators. The flux drift must be below the specified limit whilst the device satisfies other stringent specifications such as, 500 V galvanic isolation, 14-bit ENOB and environment magnetic field tolerance up to 10 mT. This paper presents the results of some of the tests performed on the integrator prototypes developed. These include tests to verify the integrator drift during long experiments when subjected to different conditions, e.g., imposition of a common mode voltage and input signals with a frequency spectrum that challenges the design limits.