Tips to Reduce Noise

Conducted Noise: Conducted noise occurs when the signal is in electrical contact with a noise source.  This is because the noise current source and our signal share a common path. This usually takes the form of a ground loop, an extra ground connection between 2 components with different internal potentials.  The ground loop acts like an antenna, effectively picking up interference, leading to a system ground reference that is no longer stable.  However subtle, the differences in potential can induce lots of noise.

 

Schematic of Ground Loop

Ohms Law yields 10V/100ohms = 0.1A flowing in the noise loop.  The tether has a resistance of 10 ohms, 0.1A*10ohms = 1V.

Real World Example



The picture above demonstrates a ground loop situation that might occur in the laboratory.  Introducing 2 different ground connections can lead to induced noise.

Solution: Provide a common ground.  Plug in necessary electronic devices to a power strip with a common ground which should help eliminate ground loops in your recording setup.  Start simple using the most basic connections during the equipment setup process and remove unnecessary ground connections. 

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As shown below, the output pinouts of various NeuroNexus probe connectors vary with Probe Package.  The input connector on the ADPT-HS-XX-N2T-YY is always the same and works with all the probe packages shown below.  The probesite mapping to Neuralynx A/D channels is different for each Probe Package.  Nexus configs presaved in your Neuralynx Configuration Folder may need to be updated to reflect the most current version of NeuroNexus pinout.