What is the background signal?
The background signal is made up of both optical and electrical signals. The optical noise is composed of an extraneous signal caused by unrelated substances during the measurement.
In a laser diffraction particle size analyzer, the background signal is made up of optical interference from the medium, which can be liquid or air, and the cleanliness of the sample cell, e.g., a small number of impurities that may exist on the cell window, creating signals with low intensities on the left side of the signal diagram. These background signals need to be measured prior to the particle size analysis and later removed from the measurement signal, which improves the measurement accuracy.