TABLE OF CONTENTS Measurement began our might
(W.B. Yeats)
Overview. Low-noise design of electronic circuits requires, among other things, reliable noise models. Many models have been detailed in Chap. 7 for various devices such as bipolar transistors, field-effect transistors, operational amplifiers, etc. Their common feature is a need to find proper numerical values for some noise coefficients, adjusted according to measured data. On the other hand, noise performance measurement is of paramount importance to the manufacturers of semiconductor devices, integrated circuits, resistors, and passive components, in order to provide useful information to the designer.
However, measuring noise signals is not a simple task, because in contrast to conventional signals, intrinsic noise has very low amplitude and power levels. Nowadays, many automated measuring systems exist, offering many capabilities. Unfortunately, they are expensive, and not all electronics laboratories are able to purchase them.
The aim of this chapter is to review some classical noise measurement techniques, that can be successfully employed with the typical equipment available in any conventional laboratory.
Definition. A noise source is a device delivering a signal with a random amplitude [220].
Classification. There are two categories of noise sources:
Primary standard, which delivers a noise signal resulting from a known physical process, whose power can be accurately predicted. The classic example is a resistor at temperature T, producing an available noise power calculated with (3.10), i.e.
Secondary standard, which must be calibrated against a primary standard. A typical...
