ANALOG button (button #1)
DIGITAL button (button #2)
LAMP (button #3)
Left-click each button to activate or deactivate.
Listen to the sound of ANALOG and DIGITAL separately with the LAMP button deactivated.
Now listen to the sounds again with the LAMP button activated. (You may need to increase the volume of your speakers to detect the variance.)
What's Going On?
Both the analog and digital transmission lines are wrapped around the fluorescent lamp. When the lamp is off, there is no noise introduced into these lines. When the lamp is on, it produces noise spikes which are coupled into the transmission lines. This noise will affect the analog but not the digital signal.
You are comparing the results of Analog and Digital transmission. Analog transmission is low-cost and simple but it is susceptible to noise. Digital transmission has much better noise immunity but it requires some electronics to convert from Analog-to-Digital and then back from Digital-to-Analog. This is necessary because humans can only understand analog signals.
There's More!
Even with Digital transmission there is always the possibility that high noise will still corrupt the data. More electronics can be added to add codes to the data stream. These codes verify the accuracy of the received data and can even be used to correct simple errors. If the received data is in error and cannot be corrected, the receiver can ask the transmitter to re-send the data. This is like asking a friend to repeat himself is you didn't understand what he said.
