TABLE OF CONTENTS In frequency domain measurements, electronic noise is a concern in two distinctly different ways The first case is when the measurement of a particular parameter is affected by the presence of unwanted noise Here, the noise is a nuisance For example, we could be measuring the distortion of a particular amplifier with the amplifier's noise getting in the way The second case occurs when the noise present in the system is the parameter to be measured In that same amplifier, we may want to measure how much noise is present at the output Many of the same principles apply to both cases, but it is important to focus on whether the noise is the measurement or whether it degrades the accuracy of the measurement
The electronic noise present in our measurements may come from the Device Under Test (DUT) that is being measured or may be generated internally by the analyzer If the noise of the DUT is to be measured, the analyzer's internal noise must be significantly lower than the DUT noise
Many waveforms that we wish to measure can be easily characterized in the time domain For instance, a sine wave can be completely described by its amplitude, frequency, and phase Once we know these values, the instantaneous voltage of the waveform can be predicted for any arbitrary instant in time Such a waveform is said to be deterministic Noise, on the other hand, is random in nature such that...
