| 摘要 |
PURPOSE:To correct a gain drift due to temperature change by comparing an output of a high speed D/A converter with an input data and adjusting the gain of the said converter so that the error is made zero. CONSTITUTION:A digital input data 11 is fed to a high speed D/A converter 10, where the data is converted into an analog voltage 12. On the other hand, when switches 71, 72 are conducted by a timer circuit 20, an integrator 30 integrates the voltage 12 and a data integrating device 40 integrates the data 11. The data subject to integrating 40 is converted into an analog voltage with high accuracy by a low speed D/A converter 50. After a fixed time is elapsed, the circuit 20 cuts off the switches 71, 72 and conducts switches 73, 74. Thus, an output of the integrator 30 and the converter 50 is fed to a comparison adjusting device 60, which detects an error of the output of the integrator 30 and the converter 50, and a reference voltage Vref of the converter 10 is adjusted so as to zero the error. |
