Figure 2.18. This is a graph of the output of a high pass filter with a square wave input. In part eh the wave starts at zero, rises very quickly to the height of the original square wave then immediately starts to decay exponentially to zero. Once it reaches zero it stays there for the length of time of one half of a cycle of the original wave. Then it suddenly drops to a negative value equal to the height of the original wave and quickly returns to zero. It stays at zero for the rest of the period of the original wave. This repeats until the wave ends on the right. In part b The wave starts at zero and very quickly rises to the height of the original square wave. Then it descends exponentially until it is near zero at the end of the first half of the original wave. There is no flat portion as with the wave in part eh. The wave goes negative to a value equal to the height of the original square wave. Then it returns exponentially to nearly zero. It rises again and repeats until ending on the right. In Part b the wave resembles a square wave again except that the parts that are supposed to be flat, top and bottom, are sloping down to the right on top and up to the right on the bottom. The rise and fall portions are the same length as those of the original square wave. End verbal description.
Go back.