| 摘要 |
PURPOSE:To apply A/D conversion at high sped with high resolution by writing once the result of comparison corresponding to one period between an output of a D/A converter and an input analog signal on a RAM, reading it by a microprocessor and revising data supplied to the D/A converter. CONSTITUTION:When an output of the D/A converter 3 is larger than the input analog signal Ea, an output of the comparator 2 goes to 0 and is written on the RAM 5, and when the output of the converter 3 is smaller, the output goes to 1 and is written on the RAM 5. When the write corresponding to one period is finished, the microprocessor 8 changes over respectively channel circuits 4, 7 and a MUX 10, and when the content of address 0 of the RAM 5 is discriminated whether or not is is '0', and when '0', M(=4016) is subtracted from the content of the address 0 of a RAM 6, and when '1', the M is added. Similarly, the content of the RAM 6 is updated from the address 1 to the address (n-1). Then the M is changed into M/2 (=2016), and the same operation is executed. Then the value adding/subtracting the M from 1016 to 0116 is repeated until the relation of M<1 is obtained by the sequential comparison method and n sets of A/D-converted values are obtained from the RAM 6.
|
