A Recommended Standard Resistor-Noise Test System

Summary--This paper describes a recommended standard resistor-noise test system, with the theory of operation given in considerable detail. The system provides for the measurement of a definitive resistor-noise quality Index. This Index, the "microvolts-per-volt" Index, is a modified form of the "conversion gain" index formerly used at NBS. The Index is a decibel expression for the number of microvolts of noise per volt of applied dc voltage transmitted in a frequency decade. A practical example is given to illustrate how the Index may be used to calculate the magnitude of current noise generated by fixed resistors in a given application. To complete the example, the combined effects of thermal noise, tube noise, and current noise are then considered. A description is also given of an existing test set which is based upon specifications associated with the recommended measuring system. The full specifications for this set are given and distinctive design features are discussed. The simple operation of the test Set and the computation of the Index are carefully explained.