| 摘要 |
In a D/A converter in a deflection system of an electron beam exposure device, the most significant bits (m bits) of input digital data consisting of n bits are input into a decoder circuit, and 2m D/A converters which correspond to the m bits are provided. The data consisting of the least significant bits (n-m bits) is input into the 2m D/A converters via 2m gates, respectively. The decoder circuit is constructed so as to control the 2m gates so that when the content of the data of the m bits is S, the first to S-th data of the 2m D/A converters is all rendered to be "1", the data of the (S+1)-th D/A converter remains the same as the data of the n-m bits, and the data of the (S+2)-th and subsequent D/A converters is all rendered to be "0", the sum of the outputs of the 2m D/A converters being applied to a coil which deflects the electron beam.
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