Very low noise DC power supply

All electronic equipment where large S/N ratio is requested for the signal processing is very sensitive on disturbances coming from power supplies. This is especially true for high accuracy measurement equipment. Then simple solution is to feed such equipment from accumulators or batteries; nevertheless, this brings problems with their servicing. This contribution presents the results of study of noise disturbance of laboratory power supply on high pure sine-wave signal source and describes a design of realized special power supply with minimum noise.