Thermal noise occurs in all transmission media and communication equipment, including passive devices. It arises from random electron motion and is characterized by a uniform distribution of energy over the frequency spectrum with a Gaussian distribution of levels.
An occluded front is formed when a cold front overtakes a warm front. and usually form around mature low-pressure areas. The cold and warm fronts curve naturally poleward into the point of occlusion, which is also known as the triple point.
Each different kind of front causes a differentkind of weather.A cold front is when a cold air mass pushes into a warm air mass.The heavier cold air sinks and slides in under the warm air. The coldair forces the warm air steeply upward along the front.