| 摘要 |
PURPOSE:To remove switching noises from a multiplier for digital and analog values by adding an output from a DA converter in which an analog input is applied to its reference voltage terminal to the output of a DA converter of which reference voltage terminal is grounded. CONSTITUTION:An analog output proportional to the product of a digital input inputted from a data latch 36 to an input terminal 1a and the analog input of a terminal 12a is obtained from a terminal 13a of a DA converter 11a, and an analog output proportional to the product of the complement of a digital input and an analog input is obtained from a terminal 14a. Since an input terminal 12b is grounded, no output is generated from output terminals 13b, 14b of a DA converter 11b. The output of an operational amplifier 39 is inverted, the inverted signal is applied to an operational amplifier 38 and the multiplied result is obtained from a terminal 22. Switching noises in respective DA converters have reverse polarity each other at a connection point 44, so that the switching noises are offset. |
