SignalsEverywhere: Measuring Filters with RTL-SDR, a Noise Source and Spektrum
In her latest video Sarah from the SignalsEverywhere YouTube channel describes how it is possible to use an RTL-SDR to measure RF filters when combined with a noise source and the Spektrum SDR software. In the video Sarah comprehensively explains how to set all the various parameters in Spektrum, before demonstrating a filter measurement with a noise source. Sarah explains how the power measurements may not be entirely accurate, however it is enough to get some idea about the shape of a filter.
Measuring Filters With RTL-SDR and Noise Source. Spektrum SDR Spectrum Analyzer
NOTE: This blog is not the place to attack the presenter on the linked video, and personal attacks or vile comments will be removed. As long as the presenter is providing relevant technical information, we simply do not care what gender or orientation they are.
Using a broadband noise source for measuring anything but passive networks is asking for trouble due to possible DUT overload and unwanted products that are often impossible to see. Using a broadband noise source with active circuits while being able to trust the results requires careful a-priori analysis of the cascade gain, dynamic range, and noise budgets.