| 摘要 |
Digital signals, in particular PCM signals, each comprising a number of bits, are converted into analog signals with a R-2R chain network which has series resistors each having a resistance value R and shunt resistors having a resistance value 2R, by feeding a constant current into a connection point between the shunt resistor at one end of the network and the adjacent series resistor. The other end is terminated by the resistor which has a value 2R and, in order to convert a digital signal of a number of bits corresponding to the number of shunt resistors, those ends of the shunt resistors which extend away from the series resistors can be connected, in accordance with the bits of the digital signal, either directly to the base of a constant current source or to a summation current line which is virtually maintained at the same potential and which forms an analog signal output, all the resistors of the network being formed by the source-drain paths of MOS transistors which are integrated on a single chip and which are connected individually and in series and are identical to one another.
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