Noise Source and Noise Measurement Basics

Gregory covers the essentials of Noise Sources and Measurements, focusing on the use of a BJT transistor as a noise source. The BJT is configured with a reversed bias at its base-emitter junction, followed by a series of common-emitter amplifiers.

To analyze the noise at the circuit output, Gregory employs a Spectrum Analyzer with a noise marker function. This data is then used to estimate the BJT Excess Noise Ratio (ENR), factoring in the noise floor and amplification gain slope of the measurement setup.

The results are presented as Noise Power Densities and Noise Temperatures, chosen for their convenience in respective calculations. This approach allows for a straightforward yet thorough exploration of the noise characteristics.

BJT PN Junction Noise Source https://gusbertianalog.com/bjt-pn-junction-noise-source/

Video about Noise Temperature and SNR https://youtu.be/if_e92rpsNY

This video was made possible by Patreon support: https://patreon.com/allelectronics

00:42 - Circuit overview 01:32 - Motivation for the measurements 02:54 - Noise characteristics 04:14 - Noise Power Density 05:48 - Reverse-biased base-emitter junction 06:46 - Spectrum analyzer measurement 08:08 - RBW and noise marker 11:24 - Automated measurements 14:54 - Amplifier gain de-embedding 17:10 - Excess noise ratio ENR 19:00 - Spectrum analyzer noise floor correction 23:04 - Circuit description 26:04 - Noise from Zener effect and Avalanche Breakdown ... https://www.youtube.com/watch?v=i_CPkmV_ZbQ