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To further reduce the offset, the modulator is chopped at system-level. A chopper switch at the input and a switch at the output periodically reverse the polarity of the input signal and the bitstream. To avoid disturbing the operation of the modulator when chopping, its state is also inverted by swapping the integration capacitors of both integrators. The chopping is done at a slow speed to make errors due to charge-injection in the chopper switches negligible.