INTRODUCTION

The following noise measurement method applies to transistors whose noise has a Gaussian power distribution, to transistors whose noise has a flat (white) power distribution, and to transistors whose noise has a l/f (power inversely proportional to frequency) power distribution.

Figure 1 shows a suitable method for measuring the transistor noise figure at frequencies equal to or less than 20 kHz. The values for the generator source resistance (as seen by the transistor), Rs, the d-c operating conditions, and free-air, lead or case temperature will depend upon the application and upon the optimum conditions for any particular device. These quantities, as well as the test frequency, should be specified. Common-emitter (common-source) configuration is assumed unless otherwise indicated.