Coupling to revenue Revenue by digital signals, in particular PCM signals, corresponding to these entries analog spend

摘要

A voltage corresponding to the signal bits is applied to the free ends of the leakage resistors, and an analogue voltage corresponding to the respective digital signal is collected from the junction point between the leakage resistor and at least one series resistor. All resistors in the ladder network consist of source-drain paths of MOSFET's, with the series MOSFET's always conducting, and their sourcedrainpaths always having a given resistance. When leakage MOSFET's are conducting, therir resistance twice this. The leakage MOSFET's form two groups; free ends of one group are connected to a fixed potential, and those of the second group are at a different potential; gates of leakage FET's of both groups connected to the sme electrode of a series FET, are connected to alternately activated outputs of a control circuit.